XJ20 what do you think please? [Archive] - CNCzone.com-The Ultimate Machinist Community

Oldmanandhistoy

07-08-2007, 04:53 PM

I have no idea about accuracy or anything, but that price is truly amazing, and even if it had crappy leadscrews and ways, I would buy it. Some lapping and ball screws would do a lot of good.

I wonder who makes that. I think I have seen it before.

Thanks for taking the trouble to look:)

All I know is when I Googled it all I got was this one link http://www.made-in-china.com/china-products/productviewVTUmeqxuIQzN/Small-Milling-Machine-Mini-Milling-Machine.html

And this as the manufacturer.
Sunca (H. K. ) Ltd.

As for ways and ball screws they would be the first thing to sort.

John

Kipper

07-08-2007, 05:15 PM

Oldmanandhistoy

07-08-2007, 05:30 PM

Looks similar to a Warco mini mill....or a Sieg X2 (http://cgi.ebay.co.uk/SIEG-X2-MILLING-MACHINE-WITH-VARIABLE-SPINDLE-SPEED_W0QQitemZ260137115633QQihZ016QQcategoryZ12584QQssPageNameZWDVWQQrdZ1QQcmdZViewItem) They seem a little small and overated....Just my opinion though :D

Thanks Kipper,

It does look similar but if you read the specs it has far more capabilities.

X2 weighs 68Kgs approx this one weighs 175kgs

• 1000W Motor
• Drilling Capacity : 20mm
• Face Milling Capacity : 63mm
• End milling Capacity : 16mm
• Longitudinal travel : 350mm
• Cross Travel : 200mm
• Working table size: 600mm x 180mm
• Max distance spindle to table 400mm
• Spindle taper : MT#3/R8/SK30
• Spindle bore: 20mm
• MT3 spindle supplied unless specified
• Spindle Speed: 50 - 3000rpm
• Spindle Rotary Angle -90°/+90°
• Gross Weight is 175Kg.
• 1020mm x 570mm x 720mm Packing HeightxDepthxWidth
• Instructions enclosed.
• Accessories available.
• American circuit board
• 240volts 50Hz.
• Full after-sales service provided
• Accuracy report included

John

philbur

07-08-2007, 07:19 PM

To be honest it doesn't look like a 175 kg. Also the column looks a bit under sized for 1 kw. Beware, check it out further before putting your money down.

There's a reasonable chance it's a top quality boat achor.

Regards
Phil

Hi all,

I’m looking for a bench top mill to CNC convert and came across this.
http://cgi.ebay.co.uk/XJ20-Milling-Machine-in-stock_W0QQitemZ320134663753QQihZ011QQcategoryZ12584QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

I’ve searched far and wide but have found no information so I am hoping you guys will have some opinions or even experience with this one? Looks to be good value for money as it seems to be close to an X3 super but half the price.

Thanks for any input, as always it is very much appreciated:)

John

The Blight

07-09-2007, 01:19 AM

This http://cgi.ebay.co.uk/XJ20-Milling-M...QQcmdZViewItem
And this http://www.made-in-china.com/china-p...g-Machine.html
Is not the same mill.

The one on ebay doesnt look too much like the X2. The 2nd one is an X2. The one on ebay has a lot more travel and the fine feed has been moved further down on the head (which I have never seen on any X2 before). It also seems like the head is taller.

Out from the specified table travel and size, I would say that it can easily be 175kg.

I know I have seen that machine before! I will post back when I find the one I'm thinking about.

Anyway, the collumn does look a bit too small, but it's hard to tell. You should send the seller an e-mail and ask for some more pictures.

Edit: Found a supplier
http://www.amadeal.co.uk/xj20.htm
Take a look at this supplier. He has lots of machines in the UK.

Edit2: And a topic about it
http://www.modelgeeks.com/Uwe/Forum.aspx/uk-model/3665/Xx-vs-XJx

Edit3: Seems like the XJ12 is the same as the X2 mill. The XJ20 is bigger, and there is also the XJ25 which is a lot bigger.

Oldmanandhistoy

07-09-2007, 06:16 AM

Hi,

The Blight

Thanks for the other links and the trouble you have gone to.

It looks to me as if this mill is a scaled up X2. I already have the X2, bought in haste and now wish I didn’t. This one has the same power and more travel than the sX3 but the column is less beefy and it looks to use rack and pinion to elevate the head with no quill. The other big difference is the price; over here the sX3 is around £950 this one will be around the £600 mark after I negotiate an off Ebay price. So I suppose the question is it worth the saving of £350?

Philbur
Thanks for your input it is appreciated.

I agree with your point about the column and it does look like the weakest link in this machine. If I were having problems with flex I could reinforce it as has been done here http://www.homegunsmith.com/cgi-bin/ib3/ikonboard.cgi?;act=ST;f=8;t=16735;st=60 but the full height of the column. This would be a large chunk out of the £350 saving but I would end up with a stiffer column than the X3 if designed properly.

XJ25 http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=320123326475

• 1200W Motor
• Drilling Capacity : 25mm
• Face Milling Capacity : 80mm
• End milling Capacity : 20mm
• Longitudinal travel : 550mm
• Cross Travel : 200mm
• Working table size: 800mm x 180mm
• Max distance spindle to table 400mm
• Spindle taper : MT3
• Spindle Speed: 50 - 3000rpm
• Positive Spindle Lock
• Adjustable gibs
• Spindle Rotary Angle -90°/+90°
• Net Weight is 148Kg
• Gross Weight is 185Kg.
• Packing size 920mm x 600mm x 1000mm.
• Instructions enclosed.
• Accessories available.
• American circuit board
• 230Volt 50Hz (single phase)
• Detailed Accuracy Report included

This machine looks to be a much better buy at only £800 but again does the column look weak? Also this is not in stock and could be months before I could get one.

I will contact the seller of these machines as he looks to have the best prices in the UK and get more information.

John

digits

07-09-2007, 06:27 AM

Oldmanandhistoy

07-09-2007, 06:40 AM

Hi - are you opposed to buying a normal X3? If you are going to CNC it, will you make any use of the SX3's tilting head and tapping feature anyway?

Axminster have the X3 for under £700 at the moment - well, £750 delivered:

www.axminster.co.uk/product.asp?pf_id=377295

Hi digits,

I have looked long and hard at the standard X3 and am having trouble getting past the 600w motor. The last thing I want to do is in 6 months wish I had more power. I am hoping to put the mill to work to make me some money so the power is relevant. Also the extra travel of the XJ20 and XJ25 is appealing.:)

John

MIKE JEFFERS

07-09-2007, 06:45 AM

digits

07-09-2007, 06:46 AM

Hi digits,

I have looked long and hard at the standard X3 and am having trouble getting past the 600w motor. The last thing I want to do is in 6 months wish I had more power. I am hoping to put the mill to work to make me some money so the power is relevant. Also the extra travel of the XJ20 and XJ25 is appealing.:)

John

I hear that! Though, however much power you have, I'm sure you'll want more in 6 months anyway!

Have you considered a secondhand machine? If weight isn't a concern, you might find something nice here : www.homeandworkshop.co.uk/ - I haven't dealt with them myself though.

Are you going to use your X-2 to make your CNC conversion parts, or the new mill?

Oldmanandhistoy

07-09-2007, 06:54 AM

depends what your doing ,i have x1 and x3 mills the usual problems crop up
lack of size being most prevalent
but i,d recomend the x3 as a good all round mill ,however if you've got the
space a b/port interact would be my chioce. old manual j head b/ports/clones
are cheap these days too

that xj20 looks like a chester mill i've seen (as well as others)

mike

Hi Mike and thanks,

If I were to buy an X3 it would be the super version but it looks to me the XJ25 is a better option; more power, travel and a couple of hundred cheaper. If my plans come to fruition I will consider an industrial machine and a machinist to operate it but that would have to be in the future.

John

Oldmanandhistoy

07-09-2007, 07:05 AM

I hear that! Though, however much power you have, I'm sure you'll want more in 6 months anyway!

Have you considered a secondhand machine? If weight isn't a concern, you might find something nice here : www.homeandworkshop.co.uk/ - I haven't dealt with them myself though.

Are you going to use your X-2 to make your CNC conversion parts, or the new mill?

Thanks for the link,

I really don’t like the X2 so would use the new mill for making the parts and it would be a good way to get a feel of the machine before using it CNC’d .

John

Oldmanandhistoy

07-09-2007, 09:46 AM

Hi all,

The XJ20 is exactly the same as this one http://www.chesteruk.net/store/century_vs_mill.htm

So that makes it £270 cheaper:wee: ; even more if you contact the seller direct. He has at least two more in stock.

I’ve contacted the seller and it is bought and paid for will arrive Wednesday. If anyone would like to know what I think of it and some pictures please let me know.

I have now bought 3 machines form this seller and a couple of other things and would just like to comment on his prices and serves. I do feel his name should be pushed as it will save a lot of people a lot of money and if you are in the UK I would strongly recommend you contact him regarding engineering type machinery and tooling. To date his serves has been second to none.

Ebay user name harryuk123

Website address http://www.amadeal.co.uk/index.htm

I have no affiliation with this seller other than being a very happy customer.

Would anyone UK be interested in buying my X2 mill.:)

Thanks to every one who has contributed to this thread,

John

digits

07-09-2007, 10:07 AM

Oldmanandhistoy

07-09-2007, 10:52 AM

Wow, you don't hang around, do you? :)

Congratulations on the new machine - I thought it looked familiar -well done on that considerable price saving over ChesterUK - you can spend that on some nice tooling :)

Have you got a seriously strong table and some way of lifting it up there - that's a whole load heavier than an X-2 - which is why I didn't consider it in the first place - can't believe it's lighter than my DIY build has ended up though (chair)

Have fun, and please post some pics :)

:cheers:

Thanks digits,

As you will know the saving I made and then some is already spent on more tooling. Not going to think about how much this is going to cost to CNC but I am sure it will be a lot less than the sX3 with fourth axis ready converted at over £3000.

As for the bench and lifting; that is going to be fun and I am looking at buying the bench and tray from ChesterUK at £211.50.

As for pic’s I will do; Imo this is a machine well worth considering especially if you are looking at a super X3 but time will tell. Also need to consider the availability of parts but I don’t anticipate that being a problem. The XJ25 would be even better and still far less than the sX3. 500mm X 200mm Y and 200w more power. Better leave that one otherwise I will be regretting not waiting for one (he will have them in end of August I believe and around £650 :eek: without the power feed)

John

david_geng

07-09-2007, 11:26 AM

There a few Chinese factories making such milling machines. They are more or less the same. Since you are going to get a report for each machine, the quality should be fine.

The price is not that amazing, you can get about half of that if you are in China.

PS. You might need to learn a bit Chinese to get that price ;*)

Oldmanandhistoy

07-09-2007, 11:41 AM

david_geng

07-09-2007, 02:35 PM

Hi,

If I lived in China I would probably get less than a quarter in wages so it still works out cheaper over here(wedge) :) lol

John

If you work for a company in western country, and they send you back to China for business, they would pay you extra for living there. So whether you earn less or not is still a question. However, such bench top mill in China is definitely a lot lot cheaper. I feel some people are just greedy by importing the machines and charging double price, but they call it business. Sorry for my off-topic.

Oldmanandhistoy

07-10-2007, 04:25 AM

If you work for a company in western country, and they send you back to China for business, they would pay you extra for living there. So whether you earn less or not is still a question. However, such bench top mill in China is definitely a lot lot cheaper. I feel some people are just greedy by importing the machines and charging double price, but they call it business. Sorry for my off-topic.

I’m guessing your talking about the likes of ChesterUK £895 and not http://www.amadeal.co.uk/index.htm at only £625. If yes then I agree as the fact I got it so much cheaper (less than the Ebay price for a direct sale) proves that Chester UK are ripping people off. In fairness though I would imagine there is a lot of paper work and other over heads to take into account.

John

flannman

07-10-2007, 04:43 AM

Hi all

Just to let you know i purchased an xj20 about two months ago from Harryuk and am very pleased with it. I have finished my retrofit with dc servos and ballscrews on all axis and have got to say the performance of the machine is good. I did have a problem with the speed controller which stopped working but a quick email to the seller and another one was in the post the next day so the after sales is excellent. I will try to post some pictures and movies later on this week.

Regards

Lee

Oldmanandhistoy

07-10-2007, 05:06 AM

digits

07-10-2007, 06:34 AM

So what sort of performance can you get from this class of machine - and is it more down to motor power or overall rigidity?

Cheers.

digits

07-11-2007, 03:20 AM

Oldmanandhistoy - so has your new toy arrived yet? :)

Oldmanandhistoy

07-11-2007, 04:07 AM

Oldmanandhistoy - so has your new toy arrived yet? :)

Morning digits,

No it’s not here yet but will be some time today.:)

I was busy yesterday afternoon building a bench for this 21 stone beast to sit on and painting it at midnight. Still have an oil tray to sort out so the machine will have to sit in the box till I get it all ready. Decided to build a bench so I have room for my coolant system to sit inside. You can call me John btw; must be a pain typing out my username.

John

digits

07-11-2007, 06:10 AM

Morning digits,

No it’s not here yet but will be some time today.:)

I was busy yesterday afternoon building a bench for this 21 stone beast to sit on and painting it at midnight. Still have an oil tray to sort out so the machine will have to sit in the box till I get it all ready. Decided to build a bench so I have room for my coolant system to sit inside. You can call me John btw; must be a pain typing out my username.

John

Hi John - I'd never thought of converting the mill's weight to stones - it's just a fat metal friend when you put it like that!

What sort of cooling are you planning? I am pulling my hair out trying to perfect my flood enclosure - assuming we get a summer, stagnant pools of coolant under the machine are something to avoid at all costs!

Cheers.

Oldmanandhistoy

07-11-2007, 06:30 AM

Hi John - I'd never thought of converting the mill's weight to stones - it's just a fat metal friend when you put it like that!

What sort of cooling are you planning? I am pulling my hair out trying to perfect my flood enclosure - assuming we get a summer, stagnant pools of coolant under the machine are something to avoid at all costs!

Cheers.

Just thinking in body weight for when it comes to moving it onto the bench.

I have a flood coolant system 27lt tank and 12lt’s/min flow; should be enough I hope. It was the one I gave the link to in your thread.

Could just buy a tray at around £50 but I resent spending that on a large tin tray so am looking around for an alternative. I was looking around B&Q (hate that place lol) and the nearest I have found was a concrete mixing tray but it was too big; any ideas? Might have to find a sheet of tin and make my own. Seen a nice tray made from ply and fibreglass some where on the zone so might see if I can find it again and go that way; like you say needs to be right.

John

digits

07-11-2007, 06:43 AM

Just thinking in body weight for when it comes to moving it onto the bench.

I have a flood coolant system 27lt tank and 12lt’s/min flow; should be enough I hope. It was the one I gave the link to in your thread.

Could just buy a tray at around £50 but I resent spending that on a large tin tray so am looking around for an alternative. I was looking around B&Q (hate that place lol) and the nearest I have found was a concrete mixing tray but it was too big; any ideas? Might have to find a sheet of tin and make my own. Seen a nice tray made from ply and fibreglass some where on the zone so might see if I can find it again and go that way; like you say needs to be right.

John

What sort of tray can you get for £50? B&Q want £25ish for 1m x 0.5m x 1mm of steel sheet - so that seems like a bargain! How big was the mixing tray? Remember you need to practically double the table size of your mill to allow for the travels and the motors hanging off where the handwheels used to be. My tiny X-1 lived in a 1.2m x 1m x 1m box!

I hate fibreglass after my attempts to make a coolant tray from it - very smelly and very much more tricky to use than I'd expected - I also ended up with a very rough surface that made chips stick like velcro!

Oldmanandhistoy

07-11-2007, 06:57 AM

What sort of tray can you get for £50? B&Q want £25ish for 1m x 0.5m x 1mm of steel sheet - so that seems like a bargain! How big was the mixing tray? Remember you need to practically double the table size of your mill to allow for the travels and the motors hanging off where the handwheels used to be. My tiny X-1 lived in a 1.2m x 1m x 1m box!

I hate fibreglass after my attempts to make a coolant tray from it - very smelly and very much more tricky to use than I'd expected - I also ended up with a very rough surface that made chips stick like velcro!

http://www.warco.co.uk/ gives separate prices for benches and trays with their milling machines; I haven’t contacted them but I would assume they would sell them separately. I may go that route and save myself the hassle.

Thanks for the info about the fibreglass will have to rethink that now.

John

digits

07-11-2007, 07:08 AM

http://www.warco.co.uk/ gives separate prices for benches and trays with their milling machines; I haven’t contacted them but I would assume they would sell them separately. I may go that route and save myself the hassle.

Thanks for the info about the fibreglass will have to rethink that now.

John

When I thought fibreglass, I though I'd end up with a nice smooth surface like a boat or an Elise ;) What I didn't think about though was that these things are made using a mould. You put some magic stuff called gel-coat into the mould (as well as magic mould release) and then layer up the glass and resin. The outside of the part stays rough and nasty looking, but as this is actually the inside, it doesn't matter - it's the side facing the mould that is glassy smooth, so unless you're going to build an anti-try first, you will end up with a smooth side on the outside of the tray! I also didn't have much faith in my abilities to produce a waterproof fibre-glass pannel, but you may have better luck/more skill!

As for those Warco trays - aren't they too small for flood coolant collection, and don't they have bolt holes through the bottom for mounting a specific mill base?

Oldmanandhistoy

07-11-2007, 07:37 AM

As for those Warco trays - aren't they too small for flood coolant collection, and don't they have bolt holes through the bottom for mounting a specific mill base?

Very likely the case.

John

MIKE JEFFERS

07-12-2007, 03:57 AM

Oldmanandhistoy

07-12-2007, 04:12 AM

digits

07-12-2007, 05:24 AM

get youself to your local community recycling depot or the tip as it's more commonly known and have a rake thru the washing machines/dish washers
some have a lid that is very useful as a tray 600x600x30 think indeset
do this well thats where i got mine
try your local blacksmiths for sheet steel ,b&q £25 for 1m sq about 4 times to much

mike

Yep, B&Q's prices are extremely high - but they are open after work, and easy to get to. Most of my metal came via the internet - it's just a pain having to be in to accept delivery - anyone know if Metalsupermarkets are open on Saturdays?

Edit: Yes, they are - I've asked for a quote.

itsme

07-12-2007, 08:39 AM

Hi there,

I've got a Chester Century (XJ20) mill which I am busy collecting CNC parts for. I have only done a few manual cuts on it and it seems amazingly rigid after my X1 (no surprise there).

As far as quality is concerned, I'd say it's about what I expected for this type of Chinese machine. You will need to strip it down and give it a good clean and adjustment. Make sure you strip the whole thing, because my gearbox had plenty of iron filings in it. Another slightly shocking discovery for me, was when I found plastic (or some kind of blue non-metallic material) gears for the spindle. Curiously, this is not what the Chester salesman told me...

As for the accuracy test report that came with the machine, well, what can I say? As far as the report was concerned, I had just bought an incredibly accurate and well setup machine from the factory. As far as my measuring equipment was concerned, I HADN'T just bought an incredibly accurate and well setup machine from the factory. My oppinion on the test report is that it is a very effective sales tool, but it's not worth the paper that it is printed on.

I'm not entirely sure of the true mass of this machine, but I can tell you that it is not manageable with one person! Two of us lifted my machine off the ground onto its stand (about 1m up). It was quite a struggle and right on the limit of what we could handle. You really probably should have 3 or 4 healthy people if you are going to be lifting this machine in one piece.

Overall, I am quite happy with this machine. It does have its problems (most of which are typical Chinese assembly/finishing issues), but I think with a bit of work you should end up with a decent machine that is reasonably accurate. It also has a 3000RPM spindle speed which I believe is faster than the X3's spindle speed and from what I've seen, it seems to have more y-axis travel than the X3 too. I think someone mentioned earlier that it may have a rack and pinion for the z-axis. To clear this up, it uses a leadscrew that runs inside the column.

http://www.realbull-machine.com/en/

Regards
Warren

Oldmanandhistoy

07-15-2007, 06:56 PM

digits

07-16-2007, 04:08 AM

Hi Warren,

Thanks for the info. You said that it would require some finishing; do the ways need scraping or are they ok in your opinion?
What plans do you have for the conversion if you don’t mind me asking? Have you decided on stepper or servos, ball screws or stock screws? I’m planning to buy steppers and drives from Motion Control Products and need to do more searching for ball screw.

I have been so busy with one thing and another mine is still in the box. I plan to get it on its stand and start stripping it down tomorrow night. I could take photos of the parts as I do the disassembly; if that would be of interest to any one please let me know. If anyone has any questions please feel free to fire away and I will do my best with answers.

John

Hi John, MCP steppers and drivers worked well for me on my X-1, and I think they're pretty good value too :)

For ballscrews have you tried Marchant Dice? Most of my machine parts come from them, and apart from the fiasco with their aluminium extrusion sub-contractor, it all arrived promptly. They will also machine the screws to fit their pricey but nicey bearings.

itsme

07-16-2007, 07:40 AM

Hi John,

The ways are not too bad, but I think my z-axis is going to need a bit of scraping and while I'm at it, I may as well touch up the x and y axes if they need it. When my gibs are tightened up on the z-axis, there is lots of resistance at the top and bottom of the head's travel, but not very much in the middle of its travel. I want to get it nice and even throughout.

For my CNC conversion, I have got 220Ncm stepper motors from Arceurotrade and I will be using Gecko G201 drives. I am going to drive the leadscrews directly via Reli-a-Flex couplings (http://www.rpmechatronics.co.uk/shop/index.php?cPath=27). These couplings are not the cheapest at around £20 a piece, but they are very well made.

I have got a set of 16x5mm DINF ballscrews from Marchant Dice. These seemed like reasonable screws to me with a light preload and built-in wipers. I must just warn you, however, that there is not much space for a ballnut for the x-axis. I wasn't able to find a 15/16mm ballnut that would fit under there without modification, so I'm going to have to remove some material to make the ballnut fit (I'll probably have to machine some of the flange off the ballnut and also remove material from the mill). The y and z axes have got more room for ballnuts, but still aren't overly spacious.

Regards
Warren

Oldmanandhistoy

07-16-2007, 03:38 PM

Hi John, MCP steppers and drivers worked well for me on my X-1, and I think they're pretty good value too :)

For ballscrews have you tried Marchant Dice? Most of my machine parts come from them, and apart from the fiasco with their aluminium extrusion sub-contractor, it all arrived promptly. They will also machine the screws to fit their pricey but nicey bearings.

I have had 5 MSD drives and a few steppers from them and am happy with the quality and reliability. I now have on order another drive and 4 more steppers, 3 for the mill and 1 for an upgrade for my CNC router. BTW do not buy from their Ebay shop go direct to their website saves on P&P.

As for ball screws I think it may be worth looking at importing especially with the £ $ rates at the moment but we will see.

Hi John,

The ways are not too bad, but I think my z-axis is going to need a bit of scraping and while I'm at it, I may as well touch up the x and y axes if they need it. When my gibs are tightened up on the z-axis, there is lots of resistance at the top and bottom of the head's travel, but not very much in the middle of its travel. I want to get it nice and even throughout.

For my CNC conversion, I have got 220Ncm stepper motors from Arceurotrade and I will be using Gecko G201 drives. I am going to drive the leadscrews directly via Reli-a-Flex couplings (http://www.rpmechatronics.co.uk/shop/index.php?cPath=27). These couplings are not the cheapest at around £20 a piece, but they are very well made.

I have got a set of 16x5mm DINF ballscrews from Marchant Dice. These seemed like reasonable screws to me with a light preload and built-in wipers. I must just warn you, however, that there is not much space for a ballnut for the x-axis. I wasn't able to find a 15/16mm ballnut that would fit under there without modification, so I'm going to have to remove some material to make the ballnut fit (I'll probably have to machine some of the flange off the ballnut and also remove material from the mill). The y and z axes have got more room for ballnuts, but still aren't overly spacious.

Regards
Warren

Thanks again for the info and especially the coupler link, not to bad a price. Looks like I will have to do some work on my X2 mill after all.

I had a couple of mates round earlier and we got the mill on its base; wow its heavy. Will be going back out very soon to have a good look and strip down the X and Y axes ready for breaking them in. This will give me a chance to have a look at the ways and dovetails (fingers crossed they don’t need too much finishing).

Pictures anyone?:)
John

digits

07-30-2007, 08:19 AM

Any updates John?

Oldmanandhistoy

07-30-2007, 08:11 PM

Any updates John?

I’ve been busy scraping in the ways; got the X and Y to +/- 0.005mm (0.0001968498”) just a bit more to do on the table. Then will take a look at the Z axis.
I’m a bit of a perfectionist by nature so don’t mind the extra work but there is still a possibility at this stage I may go back and look for more accuracy.
I’ve also just seen some one post that they are getting the longer table from the XJ25 (800mm/ 550mm of travel) so will be looking into that. There is also a simple mod I can do on the Y to give 215mm but not sure if I will need it so am going to leave that for now.

I’ve been taking pictures along the way so when I have completed the strip down, reassembly, taken some DTI measurement and done some test cuts will post them here. Keeping in mind I have not seen close up an X3 and I am a dab hand with a scraper:cool: I believe at this point I made the right choice between the two machines.

I’ll be back,:)

John

Oldmanandhistoy

08-15-2007, 06:42 PM

I’ve got the X and Y axes scraped in still need to do the Z.
I’ll let the before and after pictures do the talking :)

John

EDIT: Please note the bluing in these pictures is far too heavy for scraping and was applied for the benefit of the photos.

itsme

08-16-2007, 03:59 AM

Oldmanandhistoy

08-16-2007, 01:05 PM

Hi John,

I am planning on starting my conversion in the next week or two - I now have just about all the parts needed. I'm going to start with scraping all the ways. It seems like it is needed.

I have never done any scraping before, so I guess I have a lot to learn. I bought a few scrapers and some marking blue, but am having trouble finding a decent reference flat. Would you mind posting a photo of your reference flat as well as one of the profile of your scraper? The reason I would like to see the profile of your scraper, is because I could only find scrapers with a square end. I have been fiddling around on some scrap iron to test them, and the square corners tend to gouge out little grooves. I am thinking that a rounded end would be more suitable, but am seeking confirmation on this.

Have you sorted out any ballscrews and other hardware yet?

Regards
Warren

Hi Warren,

I did a quick search and found this which is worth a read through.
http://www.cnczone.com/forums/showthread.php?t=11874&highlight=lapping+the+ways
Have a look at post # 26 for more pictures of scrapers; I would very much like his homemade dovetail references.

Pictured below are what I use, it includes a camel back straight edge, a surface plate and my nearly worn out scraper. Pictures of scraper are poor but other link will make it clear if these don’t. Scraper is ground to approximately 50mm diameter. As you will see from the picture my scraper is an old file; if anyone wants to make their own be sure to heat it to cherry red and quench it in water with a layer of oil on top to harden it.

As yet I have not bought anything for the conversion other than stepper motors and drives. I want to do lots of research before I do.

John

EDIT: Forgot to say other than the surface plate and straight edge I used the saddle as a reference after it was scraped.

itsme

08-17-2007, 02:57 AM

Hi John,

Thanks for posting that information - it was very useful. I'm going to grind a slight radius onto the end of my scrapers.

Just to double check, did you scrape the saddle first (for both the x and y axes) using the straight edge as the reference and then scrape the x and y axes using the saddle as the reference? Did you take any measurements while scraping to check if the two slides from any particular axis were on the same plane?

I'm still searching for a decent reference edge, but hopefully I'll sort something out soon and then I can begin scraping.

Warren

Oldmanandhistoy

08-17-2007, 06:33 AM

Just to double check, did you scrape the saddle first (for both the x and y axes) using the straight edge as the reference and then scrape the x and y axes using the saddle as the reference? Did you take any measurements while scraping to check if the two slides from any particular axis were on the same plane?

DISCLAIMER: I will describe how I did my scraping but I am FAR from being an expert so the methods I used may not be correct. I did think carefully about how I would accomplish the task before I touched anything. It would be nice if someone with experience could read this and correct things if necessary.

In brief how I did my X and Y was to start by bluing up both sides of my saddle using the surface plate as a reference. I then scraped the flattest side of the two sides. Then I placed the saddle back onto the surface plate with the scraped side down. With my DTI I found the lowest point on the four corners, set my DTI to zero and then went back to the other three corners and scraped a reference mark to zero with my DTI. Using my reference marks and the surface plate I scraped the other side. Now I had a reference for my table and the base of the machine.

I did the table next; first checking the table surface for flatness. To do this I used my DTI set to zero on the surface plate with about a 150mm reach. I moved the DTI base to various points on the table and swept an arc watching for any deviations from zero. I am pleased to report that my table was within 0.05mm. I double checked the table with my camel back, from end to end and then across the corners but if you are careful with the DTI this is not absolutely necessary imho. I then placed my table upside down on the surface plate. Again using the DTI I found the lowest point on both ways and set it to zero. Then I scraped reference marks to zero every 100mm on both ways. Using the saddle for bluing the ways and the scraped reference marks I scraped in the table. I again used my camel back a couple of times on the ways to check full length of the table to make sure they were straight but again imho this is not absolutely necessary.

The ways on the base of the machine I did in a similar way to the table again using the saddle to blue the ways and the DTI set to zero on the surface plate to check overall flatness and that both ways were on the same plane to each other.

I hope all that made sense but if not please feel free to ask me to clarify a point if needed.

All this scraping take a considerable amount of time and effort but imho is well worth it; how are you going to make accurate parts on an inaccurate machine. Don’t get me wrong I am not saying that the machine is not accurate enough as it came out of the box but like I said in an earlier post I am a perfectionist by nature so wanted it to be as accurate as I could possibly get it. Also I gave a brief description of how I did it; there is more to it than I described.

One last point; by scraping the ways there is a possibility that the gib’s will no longer be wide enough and may need replacing.

John

itsme

08-18-2007, 10:37 AM

Hi John,

Thanks for going to the trouble of writing all that up. It generally seems to make sense.

I managed to find a cast iron surface table yesterday, so I should be scraping the mill any day now. I've been practising on some scrap cast iron today and I think I'm getting the hang of it.

Have you started on your z-axis yet? I think my z-axis is going to be the one that needs the most work.

Warren

Oldmanandhistoy

08-18-2007, 12:29 PM

No probs with the right up just hope it helps.:)

I have been busy finishing off the stand which I self built making and hanging the doors and painting (I hate painting lol). Also because I will be using flood coolant I have been making new way covers for the Y axis see pictures.

John

itsme

08-18-2007, 04:36 PM

Hi,

I took the saddle off my mill today, and blued it all up on the surface plate. What can I say? The results are truely spectacular!!!

John, after looking at the photos that you posted of your saddle, would I be correct in thinking that the slides were surface ground from the factory? All of my slides seem to have been rough machined and then scraped (except for the table, where they didn't get as far as scraping) - there is no sign of a grinder anywhere. I get the feeling that the scraping was all done free-hand without a reference flat even being present in the room. In fact, for the y-axis slides (the worst one out of the two photos), I can clearly feel several ridges that run all the way down both sides. I would guess I am getting <5% contact on the y-axis (if I'm lucky :) ).

It is definitely a good move to make new way covers for the y-axis. My mill is now about 5 months old and has only seen maybe 15 minutes of running (without coolant, oil or any other solvents) and the way cover is already splitting in several places. I'm going to have to replace that now as well, because I also have a flood coolant system.

I'm going to start the (much needed) scraping tomorrow.

Regards
Warren

ps. In case you are wondering, I honestly did blue the y-axis properly on a surface plate with what I would consider to be a 'normal' amount of blue. I didn't just 'paint' a little stripe down the slide :) . The ridges down the slide are pretty bad and the rest of the slide hardly feels much better when I run my fingers over it.

Oldmanandhistoy

08-18-2007, 05:55 PM

Hi,

I took the saddle off my mill today, and blued it all up on the surface plate. What can I say? The results are truely spectacular!!!

The saddle ways on my machine were surface ground (as far as I know this is the norm with all Chinese machines) and I think the photo I posted may have looked worse than it actually was. If you look again at the picture it would imply that only two corners were contacting the surface plate. While it was on the plate I tested it with a feeler gauge and one corner was high at 0.03mm. I also have an X2 and all the ways are surface ground or just milled with no signs of scraping. As you will probably know this is not good due to “sticktion”. I was please to see that the way surfaces were scraped all be it with an electric scraper to provide oil pockets. One other point, I don’t know if the cast iron was aged (I hope so) but this may account for your 5% contact area which when it comes to scraping might not be as bad as it seems at present.

Not quite sure what is going on with the other side of your saddle; it looks to be rippled nether ground or milled?

To be fair and some one made a comment in a very early post, at the price it was worth the money even if all the ways needed reworking. I have never seen an X3’s ways but being the sort of person I am I would have still scraped them.

Now my X and Y axes are scraped and the dovetails lapped (done properly with a lap not just putting lapping compound on one surface and pushing the surfaces against each other) they are as sooth as silk in motion. With the table at one of its extremes and a lot of horizontal pressure from me the defection is barely measurable. I am very happy with the time and effort I put in.

Stay positive and put the time in and I am sure that you will be as pleased as I am with the results. Imho this mill was worth every penny and more and I would buy it again with no hesitation.

For anyone else reading the posts on scraping and feeling tempted, please take the time to research it as it is a skilled art imo. The Camel back straight edge was given to me by my now deceased Granddad (god rest his soul) who gave me a demonstration of his profession and I can only dream of reaching the standard he worked to.

Warren please keep me updated with your progress as it would be nice to share our experiences with this machine. If you don’t want to start a thread of your own on your CNC conversion please feel free to post anything you like in this thread. As for my new way cover if you are interested in how I constructed it please let me know (I need to see how it goes in operation to be sure it will hold up but I am confident (famous last words lol) it will work just fine.:)

Regards,
John

itsme

08-19-2007, 03:28 AM

Hello,

I am not unhappy with this mill. I think it will do a very good job after it has been tinkered with a bit. I do sometimes wonder though, what goes on in the factory... One example of this is the spindle gears. When I originally stripped the mill to clean it up, it looked like someone had inadvertently tried to change gear while the mill was running. One of the plastic gears is all ragged and mashed at the bottom. Speaking of which, I am going to look into replacing those plastic gears (maybe a timing belt or even steel gears depending on space available etc.) when the rest of my conversion is done.

I think the rippled surface of my saddle is also machined and then scraped, but the light is not good in the photo and the scraping looks somewhat 'unconventional'. I'm not entirely sure how a power scraper works, but the scrape marks seem to start at one end of the slide and continue all the way to the other end (not in perfectly straight lines, of course). If it is possible to do this with a power scraper, then that may be the reason for the ripples.

John, for your lapping, did you machine a copper/aluminium (or some kind of softer metal) lap with the required angle and then use grinding paste? How did you mark the dovetails to make sure you were removing material in the correct places and make sure the dovetails remained parallel to the slides (or slightly angled for the dovetails that take the gibs)?

I wouldn't mind seeing how you made your way cover. Is it made of aluminium sheets with some kind of hinge material inbetween?

Warren

digits

08-19-2007, 07:14 AM

Hello,

I wouldn't mind seeing how you made your way cover. Is it made of aluminium sheets with some kind of hinge material inbetween?

Warren

Me too please John - they look great, are they noisy though, and how flat do they fold?

Also, if you're going for full flood, doesn't your enclosure/table/drip-tray need to be as wide as the mill + it's full travel? This is the reason I can't fit a moving table mill in my workshop/spare bedroom!

Cheers.

Oldmanandhistoy

08-20-2007, 04:43 PM

John, for your lapping, did you machine a copper/aluminium (or some kind of softer metal) lap with the required angle and then use grinding paste? How did you mark the dovetails to make sure you were removing material in the correct places and make sure the dovetails remained parallel to the slides (or slightly angled for the dovetails that take the gibs)?

I wouldn't mind seeing how you made your way cover. Is it made of aluminium sheets with some kind of hinge material inbetween?

Warren

I’ll get back to you on the lapping it may take me some time to get it down in print (not easy to describe lol).

The way cover is simple; it’s made of 0.5mm aluminium. You maybe able to see in the picture that I have added 5mm strips in the bottom of the troughs this will hopefully make enough room for chips so as the folds close they do not get ripped open at the joints. The strips of aluminium are hinged using fish tank repair silicon rubber. It comes in small tubes from good pet shops cost me £2.99. Its very good stuff and I’ve used it a number of times for other purposes. It sticks very firmly to almost anything and does not degrade like latex does. I laid the aluminium together and used masking tape to hold it. I then squeeze a couple of beads of silicon down the length of the joint and used a wet tool to spread it flat equally over both sides of the joint (be sure to make it at least 1mm thick and about 30mm wide). It’s important to hold the folds to about 90 degrees (in the direction it will fold obviously) while the silicon curers. I did this by making the masking tape over hang the aluminium by about 50mm each end and then nipped it together while holding the joint at about the right angle. When I fixed the way cover to the saddle and column I put a strip of rubber in the joint to stop the coolant finding its way through (it was needed). If you like the idea it maybe worth asking me how the joints are holding up just in case they start coming apart in use before you make your own. I am confident that they will last but you never know. When folded they take up about 15mm. I haven’t fully tested them for noise but I don’t see a problem as the rubber will damp vibration (nothing to date).

John

Oldmanandhistoy

08-20-2007, 04:57 PM

Also, if you're going for full flood, doesn't your enclosure/table/drip-tray need to be as wide as the mill + it's full travel? This is the reason I can't fit a moving table mill in my workshop/spare bedroom!

The picture may look a bit deceptive but the tray is wider than the machine table when at full extremes. The machine table also has a drain hole at one end so the coolant does not pour over the sides in a random fashion. I have used the machine with coolant and have no problems other than a bit of splatter mainly from the cutting tool. I will be adding a couple of splatter shields which will also double as machine guard in the near future.

John

jon_m3

08-22-2007, 01:10 PM

watching this thread ill be starting my xj20 modding in a month or so`s time once ive got the bigger table.

Oldmanandhistoy

08-22-2007, 07:34 PM

watching this thread ill be starting my xj20 modding in a month or so`s time once ive got the bigger table.

Hi jon_m3,

More the merrier :)

Have you worked out everything you are using and sources for the conversion? So far I’ve got 3 MSD556 drives and 3 Nema 23 3Nm (424 oz in) stepper motors from Motion Control Products. I do have a Nema 34 stepper for the Z axis if I need it.I’ve still got to find a good source for ballscrews and other bits and pieces. I’m not in any rush to get the machine CNC’d as I would like to use it manual to get the experience and workout what the machine is capable of feeds and speeds and so on.

What I did do this evening for anyone who might be interested was fit a stepper motor on my X axis. Firstly to use as a power feed and secondly to help work out my feeds. Just for now I have it set up with Turbocnc, a very old laptop and use jog mode. I was quite surprised to be getting over 1000mm/min (40"/min) with lots of torque (unable to stop the axis with all my weight) and 1600mm/min (63"/min) rapids. These were just quick tests as it was getting late and will do more tomorrow evening.

John

itsme

08-23-2007, 11:54 AM

Hi John,

Your stepper experiments sound interesting. Were you using a 3Nm Nema 23 motor for these? As I mentioned earlier, I have got 2.2Nm motors lined up for my machine, so hopefully they should do the job well. I know others have used the same motors as mine on the X3 with good results.

I am wondering about the z-axis. Do you think a Nema 34 would be better than the Nema 23? I was going to use a belt reduction with the Nema 23, but I am having doubts. Maybe I'll leave the z-axis until someone else has done theirs :) .

I had a day off from scraping today (my elbow and hands needed a rest). I've been at it almost full time since Sunday. The saddle was relatively straighforward to do, the table a little more tedious. One of the slides on my table was sloping across its width by about 0.1mm. This meant I had to scrape about 0.1mm off the other slide (the entire surface...) in order to get them both flat and on the same plane. 0.1mm doesn't seem like much, but it took AGES to scrape it off. I haven't done the base of the machine yet, or the z-axis. I am also going to have to replace at least the x-axis gib strip, because it has just run out of adjustment. Oh well.

I need to start looking at how I'm going to go about mounting the motors and ballscrews, but only after I've finished the scraping...it sure takes some patience.

Warren

Skullface

08-23-2007, 11:59 AM

Do you have a picture of the way you mounted that x axis stepper??

I also purchased a machine from this chap, XJ12 variant. Does use rack and pinion for the Z axis.

I'm collecting parts to do the conversion to CNC, so far i have 3 of Motion Control's nema 34 high torque 80mm motors, and 3 10AMP british made drive cards.

I'm against a time restriction to start producing results, and have a limited budget at this stage. I wont purchase anything substandard, but will do limited stages of an ideal conversion just to get it running as soon as possible. once this first volume job, just drilling plates with a grid of holes, is finished i shall be able to do extra work to improve it.

Can i get away with using the standard lead screws? backlash compensate in software?
can i use the rack and pinion and still CNC? though i do hope to upgade to lead/ball screw soon as i can.

Sorry for the bitty first post.

Luke

Oldmanandhistoy

08-23-2007, 12:50 PM

Hi Luke,

I’ve posted a quick picture of my temporary motor mounting method (very solid considering) will get back but need to go out now.

L8a,

John

Oldmanandhistoy

08-23-2007, 04:01 PM

Your stepper experiments sound interesting. Were you using a 3Nm Nema 23 motor for these? As I mentioned earlier, I have got 2.2Nm motors lined up for my machine, so hopefully they should do the job well. I know others have used the same motors as mine on the X3 with good results.

The stepper I have set up on the X is indeed a 3Nm Nema 23. I bought the 3Nm knowing it would be more than I wanted but as with all the stepper’s and drives I have bought to date I go over powered. It’s nice to have the extra power if needed and it also puts less stress on the electrics (I do the same with PSU parts also).

Do you know the weight difference between an X3 and a XJ20 table; it looks like the XJ table could be heavier than an X3?

I am wondering about the z-axis. Do you think a Nema 34 would be better than the Nema 23? I was going to use a belt reduction with the Nema 23, but I am having doubts. Maybe I'll leave the z-axis until someone else has done theirs :) .

If I use a Nema 23 stepper I will very likely use a 2:1 reduction but need to look into this further and do some calculations. If I end up using the Nema 34 (4.1Nm or 580 oz in) I would go direct drive unless I needed more power.

I had a day off from scraping today (my elbow and hands needed a rest). I've been at it almost full time since Sunday. The saddle was relatively straighforward to do, the table a little more tedious. One of the slides on my table was sloping across its width by about 0.1mm. This meant I had to scrape about 0.1mm off the other slide (the entire surface...) in order to get them both flat and on the same plane. 0.1mm doesn't seem like much, but it took AGES to scrape it off. I haven't done the base of the machine yet, or the z-axis. I am also going to have to replace at least the x-axis gib strip, because it has just run out of adjustment. Oh well.

I don’t envy the 0.1mm you had to scrape that a lot of scraping. I looked at adding a shim to the back of the gib strip but it brought the gib strip to far away from the adjusting screw so was a no go. I also considered boring out the holes and increasing the screw size but decided a new gib strip was the way to go.

I need to start looking at how I'm going to go about mounting the motors and ballscrews, but only after I've finished the scraping...it sure takes some patience.

I don’t as yet foresee any problems doing the conversion I have most of it worked out in my head. The X will be as in the picture with but a more substantial motor mount. I think I will very likely mount the Y axis motor to the base and use belt drive 1:1 but this may change when I come to it and the Z like already mentioned.

John

EDIT: I forgot to mention I have had the table doing rapids of 2100mm/min but this is only with the vice mounted. I should have added a few Kg’s to give a more realistic test situation. :)

Oldmanandhistoy

08-23-2007, 04:24 PM

Can i get away with using the standard lead screws? backlash compensate in software?
can i use the rack and pinion and still CNC? though i do hope to upgade to lead/ball screw soon as i can.

Sorry for the bitty first post.

Luke

If your intention is to use the machine to drill holes then using the standard screws will not be a problem imho. Do the nuts have backlash reduction built in as the XJ20 has? If not you could very likely slit the nut and add some screws to adjust out most of the backlash or as you mentioned use software compensation.

As for using the rack and pinion on your Z; I originally bought an X2 which has R&P on the Z and gave this idea some thought. Unless you can find/come up with a good method of reducing the backlash you may be able to get away with it for drilling but again imho would be a none starter for milling. If there is a lot of backlash in the rack it may be possible to shim behind it as this will help. I personally think CNC’ing the rack would be far too problematic and would go straight to a screw.

Nema 32 motors are very large for a small mill you may get bad problems with rotor inertia.

The picture I posted will not be how I will do things when it comes to CNC’ing my mill proper as mentioned I have done it temporally to use as a power feed. If I wanted to do a quick job to use my mill for drilling only as you mentioned then I would say it is defiantly sturdy enough. The two motor stand offs are 12mm steel bar.

I hope there is something in that to help,:)

John

Skullface

08-23-2007, 05:42 PM

Nema 32 motors are very large for a small mill you may get bad problems with rotor inertia.

John

That is frustrating. I spoke to both ebay sellers of these mills, and to Motion Control and Routout, everybody thought nema 23 would be pushing it a bit really, and to be safe, 34 was the only way to go. Surely the intertia issues are partly countered by the incresed Nm ability of the motors. ie more balls to stop themselves also.

RE: Z axis screw conversion, i saw an interesting X2 conv, that had the leadscrew sticking vertically off the top of the head, so its forces acted centrally, anyone seen this, has any idea how to go about it?

hmm, i feel abuse of anothers post, and might start my own when i consilidate my thoughts. still, all relevant to that same series of mills.

thanks for your time.

Oldmanandhistoy

08-23-2007, 07:54 PM

That is frustrating. I spoke to both ebay sellers of these mills, and to Motion Control and Routout, everybody thought nema 23 would be pushing it a bit really, and to be safe, 34 was the only way to go. Surely the intertia issues are partly countered by the incresed Nm ability of the motors. ie more balls to stop themselves also.

RE: Z axis screw conversion, i saw an interesting X2 conv, that had the leadscrew sticking vertically off the top of the head, so its forces acted centrally, anyone seen this, has any idea how to go about it?

hmm, i feel abuse of anothers post, and might start my own when i consilidate my thoughts. still, all relevant to that same series of mills.

thanks for your time.

I’m no expert but its something to do with the motor over shooting its position and then bouncing back. If you take a look at some of the threads here on X2 (similar size to your mill I do believe) conversions you will find a lot of people using Nema 23 @ 1.8Nm with good results.

Hoss has a thread here about an X2 conversion with plans; it is probable you could adapt them for your own needs.

John

jon_m3

08-24-2007, 02:14 PM

well make sure you both take lots of pics for me to look at and she how things work, this scraping sounds interesting i cant wait to learn how todo that.............

not

itsme

08-25-2007, 04:14 PM

Hi,

Scraping sure is fun. I'm going to be moving on to the base of the machine tomorrow and then the z-axis. I stripped the rest of my machine down today and took a few quick measurements of the z-axis slides. I need to do more accurate and comprehensive measurements, but what I did do indicated that the end of one of the slides is >0.2mm higher than the middle (lengthwise) of the slide. This would explain why the head was so sloppy in the middle of its travel, yet almost impossible to move at the ends. I'm hardly looking forward to scraping the column after seeing these measurements, but it'll be worth it in the end (I've got to keep telling myself that...:) ).

Warren

Oldmanandhistoy

08-25-2007, 05:49 PM

(I've got to keep telling myself that...:) ).

That really made me smile :D ; but it is absolutely true. When people ask you how did you manage to get that feed rate you can tell them “blood sweat and tears” lol. A week after finishing all your scraping it will be nothing but a distant memory but you will smile like this :D and dance like this :wee: when you get smooth accurate cuts.

Let me know when you are finished and I will tell you about a cheat method I use that makes the job half as long. Only joking no other way than the hard way unless you have a power scraper which I don’t.:violin:

John

jollydog

08-29-2007, 02:18 PM

Hi
Just got a mashine like the one your asking about
the certificate from China is here
the weight is 135 kg of heavy castiron

Oldmanandhistoy

08-29-2007, 02:50 PM

Hi
Just got a mashine like the one your asking about
the certificate from China is here
the weight is 135 kg of heavy castiron

Hi Jollydog and welcome to the Zone,:)

Thanks for posting that; I got one but never got to see it or the instruction manual that came with my machine. Both where in a small pile with a news paper and some other junk mail ready for me to look over when I had more time. Unfortunately due to my other half’s eagerness to keep my so called junk under control it ended up in the bin before I had chance to file it away. Lol

John

jollydog

08-29-2007, 03:21 PM

Do you need a copy of the instruction manual ?

Oldmanandhistoy

08-29-2007, 03:28 PM

Do you need a copy of the instruction manual ?

If it were a simple case of downloading it I would be grateful for a link but I would not ask you to go to the trouble of copying it for me. So far I have not needed it and don’t envisage I will but would have been nice to give it a read through.

Thanks for the enquiry though,:)

John

itsme

08-29-2007, 04:32 PM

Oldmanandhistoy

08-29-2007, 04:52 PM

Hi,

John, I seem to have lost my instruction manual and inspection sheet, but I did have a chance to read through them both. From what I remember, you are not missing out on much...:)

I fully disassembed the z-axis today and was mildly disappointed by the column on the mill. Maybe I'm being a bit harsh on what is a hobby machine, but the column just doesn't seem to have the same robustness behind it that the table and base do.

I also managed to squeeze a 27 litre coolant tank and pump into the bottom of my stand today (it's a Chester stand and Sieg coolant system). The coolant system just wouldn't fit, but after I attacked it with an angle grinder and removed the legs, a handle and modified the other handle, it now fits in very snugly :) . I also touched up all the paint. This stand is going to work out nicely now. The coolant is on the bottom shelf and all the electronics will fit on the top shelf.

Have you made any more progress on your machine, or are you just running it manually for now?

Warren

Evening Warren,

Sounds good to me Warren.

Other than what I have done to my X axis (power feed) the only thing I have done is make a drawer style enclosure to fit above my coolant tank and wired up for 3 axis (another one to follow) it seems great minds think alike. :)

As for the column and spindle, I have as yet not touched it but plan to this week.

I think being very new to all this metal milling stuff it would be a good idea to run the machine in manual mode until I get the feel of things. Also while I am researching necessary components for the CNC’ing I might as well. Do you think it is the best way for me to go or should I just jump straight into CNC machining?

John

Oldmanandhistoy

08-30-2007, 11:35 AM

Another slightly shocking discovery for me, was when I found plastic (or some kind of blue non-metallic material) gears for the spindle. Curiously, this is not what the Chester salesman told me...

A quick post for Warren,

I’ve just got to the point of actually seeing my gears, I hope the picture shows that they are in fact all metal. So it is very likely this would have been the information your sales person had. I have no idea why yours are plastic (or similar material) I can only imagine that my machine has had some spec upgrades. Obviously for me this is a happy revelation.:)

John

itsme

08-30-2007, 01:44 PM

Hello,

John, the only positive thing that I can draw out of your last post is that when it comes time to replace my gears, I'll be able to get metal ones off the shelf (I hope) :( . Oh, and just to clarify my gear situation, not all of my gears are plastic. The two that you can see clearly in your photo are also metal on mine, but the ones that they mesh with (not so clear in your photo) are the plastic ones.

I found another interesting feature on my machine too! The part of the head that has the slides for the z-axis had a small casting defect on the surface of it. While investigating this, I decided to poke it with a scribe and the end of the scribe disappeared into the casting (I'm not sure whether I should be shocked by this or not). From what I can see, this defect is not too large and doesn't seem to be in a critical position, so I am going to work around it for now. Considering I paid the original Chester price for this machine (£900), I'm not overly impressed by all these non-standard 'features' that my machine has.

Oh well...

Warren

Oldmanandhistoy

08-30-2007, 08:38 PM

Warren,

I would send the seller of my mill http://www.amadeal.co.uk/xj20.htm an email and see what he can do. IMO he is a first class seller and I would think he would go out of his way to get you the parts you needed. The trouble will be if indeed they are an “off the shelf” parts that shelf will be in China more than likely so if they go all of a sudden it could take weeks to import them. The picture I took wasn’t very clear but the defiantly are all metal. It would be interesting to know if your seller had that machine in stock for a long time and after that machine had been imported they made some improvements. To the best of my knowledge Amedeal have a fast turn around so it is very likely my machine was only 2-3 months old when I got it.
As for the void in your casting I could not say how common that would be but I do know there are none in mine. The only defect I have found in my castings is a small cold spot on one of the base ways which I needed to stone below the surface so as not to affect things long term.

If anybody is following this thread and would like to see more pictures of the machines parts please let me know as I have a few more now in my camera.

John

itsme

08-31-2007, 03:35 AM

Hi John,

That's not a bad idea - I might send an email off and see what he has to say about parts.

On another note, I haven't touched my scraping in nearly a week, but there is a good reason for that (and I just can't help but brag about this one :) )! You'll see in the photo that I managed to find a very nice, old, Brown and Sharpe camelbacked straight edge (36" long), so I've been waiting for it to arrive in the post, which it did this morning! I'm quite impressed by the condition, considering it must be pretty old. In fact, when I opened the box, it had that distinct 'museum' smell about it - nothing quite like the smell of old iron :) .

It's back to the scraping for me with renewed enthusiasm!

Warren

Oldmanandhistoy

08-31-2007, 06:14 AM

It's back to the scraping for me with renewed enthusiasm.

Very nice find Warren,:)

When I look at the scraped face on mine it makes me feel very humble. If everything were made to this quality our rubbish tips would be rather empty. Unlike the vast quantity of Chinese (and other) discarded short life products we buy today. It will make that long Z axis a piece of cake and you’ll be finished by lunch time lol. I’ve just started scraping my Z axis saddle and am quit determined to have all my ways finished this weekend.

Pictures are my saddle before scraping and after its first blue; you will need to look closely for the blue. Even though it does not look good the error is very small and would very likely be fine for most as is but I am very fussy.:)

John

S_J_H

08-31-2007, 09:16 AM

Scraping is something I need to learn. How do you go about scraping in the angled dovetail surface and keep it square to the flat surface?

Steve

Oldmanandhistoy

08-31-2007, 01:10 PM

Scraping is something I need to learn. How do you go about scraping in the angled dovetail surface and keep it square to the flat surface?

Steve

Hi Steve,

Scraping the dovetail is very likely beyond my talents so I will lap all of mine and just scrape in some oil reservoirs. Doing lapping correctly is a very difficult task to put in writing (for me any way). I have searched the web and can not find anything that describes it. If you know of a link I would be grateful as I have a feeling Warren is going to ask me for an explanation as soon as he has finished his scraping lol.

If you want to scrape them you will need what is shown in the third last picture in this post http://www.cnczone.com/forums/showpost.php?p=95535&postcount=26 and do them as you would a way surface. I don’t know if you have read the thread the post came from but if not I think you will find it very interesting.

Hope this helps :)

Picture is my Z axis saddle half finished if anyone is interested; well one side of it anyway.

John

S_J_H

08-31-2007, 03:46 PM

Oldmanandhistoy

08-31-2007, 07:19 PM

John, So when scraping are you also using an indicator in some way to make sure the ways do not wander off at some odd angle during the process and stay in the same plane?
Yes, that is a great thread. I read all of it.
Steve

If you go back to page 4 post #47 it gives a description of how I do it. You may notice I don’t have much of a talent as a writer so if anything is not clear let me know and I’ll see if I can make it clearer. I have been thinking of doing a thread about scraping and lapping (my way) and hoping that some one with more experience would chip in with anything they did not like and describe a better method. I have not read much about doing such tasks I just used common sense and gave it a lot of thought before I started. Maybe it’s just in the blood as my granddad did it for a living and gave me a quick demonstration (many years ago now); the camel back straight edge was his. All I can say is my X and Y axes (finished) move as smooth as silk and not a sign of “sticktion” to boot. Also because of the scraping and lapping the gibs can be set pretty tight without problems. It really has made a big difference to my machine compared to how it came out of the box. I’ve spent 25 years of my life working with, setting up and trouble shooting large industrial machinery all be it as a wood machinist and that helped. Have a read through and see what you think, it would be nice to have your opinion. From what I have seen on the zone you certainly seem to know your way around a machine.
Just out of interest what do you think of the bearings on your X3 are they scraped?

John

S_J_H

09-01-2007, 06:56 PM

Ahh yes, I did read your method before(post 47), I guess I just forgot, so much info to retain!
Yes I would say you did a very good job with your method!
I have not bothered tearing down my x3 head/spindle yet. I'll just wait until it shows signs of bearing issues. Right now the spindle runout is very low. .0002" or so.
I may try scraping the x3 ways but when I indicate the table it is very flat. Only at the extremes of travel when the weight of the table overhanging the dovetails has an effect do I see any real variance.
I am sure it could be better though from scraping.
Steve

itsme

09-02-2007, 04:16 AM

Hi there,

The base is now scraped and all that is left is the z-axis. The only problem now is that my z-axis troubles are worse than I originally thought (I didn't exactly think it was good to begin with).

I blued the column slides up with the straight edge and only got a very small amount of contact on either end - just what I was expecting. I then blued the centre, ground section (the bit inbetween the slides), to find that that also only had a very small amount of contact on either end and I could get a 0.07mm feeler gauge under the straight edge at the centre. What this all points towards is a bowed column. Now, I haven't been able to measure the dovetails, but I'd imagine that those are probably bowed with the rest of the column.

I'm not sure what would have caused this bow, but I just can't help but think that the (frankly pathetic) column section has something to do with it. So, I can now scrape everything flat and probably get it to be reasonably good when it's on its back on the bench, but who's to say that when I put it back on the machine with the weight of the head that it won't just sag some more? Besides this, I'm fairly sure that the column is going to be responsible for most of the machine's vibration/rigidity troubles in the future.

John, what have you found with your column? Have you had any trouble?

I think some pondering is in order here to decide the future of my column...

Warren

ZipSnipe

09-02-2007, 08:16 AM

Hey Warren,
i noticed you got yourself a used straight edge. Are you sure it is still straight? Reason I say this is you blued two different areas on your work piece and recieved to identical results. Sounds like you should true(verify that its still a straight edge) the straight edge before any scraping is done. Otherwise you could get yourself deeper into scraping infinetly.
just a thought.

Oldmanandhistoy

09-02-2007, 10:18 AM

Hi Warren,

ZipSnipe has covered my fist thoughts. You probably have it checked by now but that would be my first move. I do know my camel back is not 100% (not as much as 0.07mm though) and have this to take into account when I do my column. I’m only 90% finished the second side of my Z saddle, as I forgot to take into account the arrangements my other half made for this weekend.
If my column is only (I say only and that is just imho) 0.07mm out over 700mm then I think I will be quite happy. When you think about the error in say a 100mm Z movement it would near impossible to measure the error. Do we really need to look for better?

Do you have a plan of action if it is your Camel back that is at fault? As said, mine is not 100% so I have been giving it a bit of thought as to what I would do when I get to the my column.

John

itsme

09-02-2007, 10:36 AM

Oldmanandhistoy

09-02-2007, 10:47 AM

Hi,

I'm reasonably confident that the straight edge is quite straight. I blued up my surface plate and checked the straight edge against that. I know the surface plate obvioulsy can't cover the whole straight edge in one go, but on several different sections that I did blue, I was getting excellent blue coverage with no signs of bow in the straight edge.

Some inconsistency in the z-axis was also expected, because of how tight the head was at the extremes of its travel and how loose it was in the middle of its travel. Some quick and rough dial indicator readings also suggest a bowed column. To sum all of the above up, I am confident that it is not the measuring equipment that is at fault here. I'm sure I'll get it sorted in the end, but it's just going to take longer than expected.

Warren

Will you be taking into account the flex of the column once loaded by the head?

I did a test for column flex before dismantling my machine. Using a DTI on the spindle with the head quite low down the column. Whilst putting a lot of weight on the top of a test bar in a collet I could not see any movement on the DTI so was quite happy not to consider adding bow (to normalise the column under load) when scraping it in.

John

itsme

09-02-2007, 11:42 AM

Hello,

I have no plans to include any bow to compensate for the head weight. I weighed most of the components this morning, found the approximate center of gravity of the head and then did a few bending calculations for the column based on its cross section and making the assumption that it was a cantilever beam. The material properties that I used were roughly in the middle of what is 'normal' for grey cast iron. What these calculations suggest is a deflection of approximately 0.06mm at the top of the column when the head is at the top of its travel. Just to clarify, the 0.07mm that I measured in the middle of my column, would result in a MUCH larger deflection at the end of the column than 0.07mm (or the calculated 0.06mm).

I'm not sure why my column is bowed like it is. I can only think that maybe some internal stresses have been relieved (possibly after machining) with a helping hand from the head hanging off it.

Warren

ZipSnipe

09-02-2007, 04:21 PM

Thats great your straightedge sounds like its true to me. Its a shame these machines have to be scraped, I always thought they looked liked well made machines compared to the x2's and x3's.

Oldmanandhistoy

09-02-2007, 07:02 PM

Thats great your straightedge sounds like its true to me. Its a shame these machines have to be scraped, I always thought they looked liked well made machines compared to the x2's and x3's.

Hi ZipSnipe,

I think the question that needs to be asked is does the X3 need to be scraped also? I have seen posted that some keep the X3’s gibs a little on the loose side to help prevent binding. I am certain that it will not be necessary on my machine. I have tested my X axis with a stepper, gibs set very snug and she runs like silk. I would very much like to see an X3’s ways just to compare. I think the machine could have been run without scraping as many/most X3 are. Considering the saving in price between the two machines it is defiantly worth going to the extra trouble imho. I’m not saying my machine is better than an X3 or as good as, the truth is I just don’t know. I do think after scraping my machine it will be better than any X3 out of the box.

I’ve posted a couple more pictures of my scraping efforts (won’t bore you with anymore promise lol). It’s the Z saddle again, as I posted a first blue and a about half way I thought it only right I should post the finished job. Not perfect but not bad either.:)

John

EDIT: looking at it now I may do a bit more tomorrow. :stickpoke

Oldmanandhistoy

09-02-2007, 08:07 PM

Hello,

I have no plans to include any bow to compensate for the head weight. I weighed most of the components this morning, found the approximate center of gravity of the head and then did a few bending calculations for the column based on its cross section and making the assumption that it was a cantilever beam. The material properties that I used were roughly in the middle of what is 'normal' for grey cast iron. What these calculations suggest is a deflection of approximately 0.06mm at the top of the column when the head is at the top of its travel. Just to clarify, the 0.07mm that I measured in the middle of my column, would result in a MUCH larger deflection at the end of the column than 0.07mm (or the calculated 0.06mm).

Warren

Hi Warren,

Will you be using a counter weight pulley system on your Z axis? I think I am right to say it would negate most of the flex problems.

I’m pleased you did the maths and came to the same conclusion as me, helps remove my doubts.:)

Since you posted I still haven’t blued up my column (you made me nervous lol) but will have to tomorrow night.:eek:

John

itsme

09-03-2007, 02:15 AM

Hi,

I'm not sure whether I'm going to use a counterweight or not. If I can get away without it, then that's the way I'd like to go.

I'm busy looking into options for my z-axis. So far, I have 2 on the list. The first is to just scrape everything down and get it all flat that way (although the dovetails will be a challenge). The second (slightly more wacky) idea that I had was to make some kind of pretensioning device that runs down the back of the column. This would allow me to get the column fairly straight so that I could then scrape it with relative ease. Once the scraping was done, this option would then even allow me to tweak the pretensioning system to take into acount the flex of the column due to the head weight.

The negative aspect of option 1 is that it'll take about 10 days and nights of scraping. The negative side to a pretensioning system is extra complexity and difficulty in adjusting the system without removing the head of the mill (I'm sure it'd need adjusting as it relaxes over time).

I think I'm going to start working on the electronics while I think about it.

Warren

Option 3 :) :

After a quick visit to a local ironfounder this morning with my column, there is now a 3rd option on the list. The owner seemed quite friendly, and said I'd be looking at around £150 for patterns plus about £60 - 70 for casting a column. Now, £200+ for a new column is expensive (considering it still needs maching etc.), but what he did say, is that I could make my own patterns and save the £150. For this option, I could alter the dimensions/wall thickness etc. to suit my setup and the new column would probably weigh in at around 35kg compared to the standard 21kg.

Clearly this is not a short-term solution and would require a lot of work, but it's still an option. It's at the bottom of my to-do list now, but I can't rule it off the long-term mill upgrade list :) .

Oldmanandhistoy

09-03-2007, 05:34 AM

Option two I have seen done a couple of different ways on X2’s but no idea where now; could have been on here or the Yahoo group. There defiantly was a discussion about a “banana” shaped column as they put it at Yahoo.

Option three sounds interesting but imho building a column support from a square steel tube or making similar from plate steel would be the way I would go. Something similar to how it has been done here http://www.cnczone.com/forums/showpost.php?p=249849&postcount=5.

John

cliveastro

09-03-2007, 07:34 AM

Oldmanandhistoy

09-03-2007, 11:47 AM

Hi John
I have a Chester Conquest mill which is an X2 by another name and although initially I didnt think it was very good I have stripped it down, replaced the head bearings and generally fettled things, it now works well.
The best thing I did was to add digital readouts and the head bearings.
I have an odd variety of X2 so nothing fits so I have a few designs done.
As you have contributed to my leadscrew questions you will know I am in the process of designing ballscrews in ready for cnc. You are welcome to any information.

Clive

Hi Clive and thanks,

I bought an X2 and still have it in its original state; unfortunately I did not get to see it in the flesh so to speak before hand. When it arrived I very quickly came to the conclusion even though it was quite a nice machine for its size it was not up to the jobs I bought it for. So I decided to go with the XJ20 after seeking advice here.

I’m a wood machinist by trade and know what difference there is using a well made quality machine. So I am going to do what I can to make the machine I have as good as it can be. Getting to the point I would very much like to know more about why you changed the bearings in your spindle and what advantages/improvement that has made to your machine. Do you think for instance that these Chinese machines need their bearings replaced immediately form new?

You may have noticed I take my hobbies quite seriously but this will have commercial uses an in prototyping in the near future as well as being a learning tool.

If you find any other good sources for ball screws I would appreciate a link to where you found them.:)

John

cliveastro

09-03-2007, 04:54 PM

Hi John
The bearings are unsheilded and they became full of swarf so I changed them for deep groove bearings.
The result was much better surface finish and more accurate cuts.

Ballscrew companies include SKF, Hiwin and Nook, there are smaller companies like Marchant dice around also. SKF are good prices but they come from France and they charge about £40 for delivery.

Where are you in the UK.

Clive

Oldmanandhistoy

09-03-2007, 05:15 PM

cliveastro

09-03-2007, 05:52 PM

Hi John
I live in East Sussex, so not too far away if you need any help.

Clive

Oldmanandhistoy

09-04-2007, 07:26 PM

Just to clarify, the 0.07mm that I measured in the middle of my column, would result in a MUCH larger deflection at the end of the column than 0.07mm (or the calculated 0.06mm).

I'm not sure why my column is bowed like it is. I can only think that maybe some internal stresses have been relieved (possibly after machining) with a helping hand from the head hanging off it.

Warren

I had my first real look at my column tonight and have to report that my column has the same problem. I checked my camel back straight edge with a tight wire and it is straight to the point it would be neigh on impossible for me to measure the error. I can slide a 0.09mm shim in between my straight edge and the way surface.

The question I am asking myself now is this standard error for this class of machine?

What would be the implications of using a milling machine with a column bowed by 0.09mm (0.0035")in a 700mm (27.56") length?

I can scrape this out with a couple of days work but will defiantly need a new gib by the time I have sorted the dovetails.

John

S_J_H

09-05-2007, 12:52 AM

John,
not to big of a deal IMO. When you consider the z-travel distance used in cutting parts the variance will be very small.

Steve

itsme

09-05-2007, 03:23 AM

Oldmanandhistoy

09-05-2007, 05:42 AM

Hi John,

At least they are consistent from one machine to another! :)

I'm not sure if you have any binding issues with your z-axis (tight at the top and bottom, but loose in the middle) like I have, but I think I have now discovered the cause of this. You may remember that the 0.07mm that I measured with a feeler gauge was on the centre ground section of the column - I didn't take any feeler gauge measurements on the ways. Well, this morning I decided to try on my ways and I could fit a 0.23mm (yes, more than 1/5th of a millimeter :eek: ) feeler gauge under the straight edge. So it appears that the centre section that contains the dovetails is bowed far less than the ways. This would account for the binding at the ends of the travel. If this is all due to distortion, then there must also be some variation across the width of the ways, as it gradually feeds in from a little bit of bow to a lot of bow. Having said that though, the 0.23mm feeler gauge did go in the full width of the way.

Did you have binding issues like this on your z-axis, John?

Warren

There is a little bit of binding going on near the bottom but nothing that would have caused problems.

I don’t know what kind of job they did on your column ways but my needed deburring otherwise I would have had a lot more than 0.09mm in there. The burrs were from the power scraping.

I have been thinking about your option 3 of a casting; instead of my idea of a steel tube why not have a cast iron pillar made and strap your column to that. The column seems to be the weakest link in all the Chinese machines imho so a support would make a world of difference to over all rigidity needed or not. Would your source normalise the castings?

Have you by any chance been thinking about adding a block between the column and the base to increase Y travel? It would gain about 15mm or even more if you didn’t mind the saddle going past the dovetail a little. I can’t think now how well centred the spindle is over the table and I can’t check either as my machine is in bits but may need another block between the head and the Z axis saddle. I have one source for of the shelf cast iron but it may work out cheaper to have them cast.

John

Oldmanandhistoy

09-05-2007, 05:57 AM

John,
not to big of a deal IMO. When you consider the z-travel distance used in cutting parts the variance will be very small.

Steve

If my column is only (I say only and that is just imho) 0.07mm out over 700mm then I think I will be quite happy. When you think about the error in say a 100mm Z movement it would near impossible to measure the error. Do we really need to look for better?

As you can see I’ve been thinking the same thing but don’t know if I can live with it especially after going to all the trouble of scraping all the surfaces. The question is would it just be foolish to spend a day correcting the error and having to make a new taper gib to boot?

John

itsme

09-05-2007, 06:51 AM

Hi,

John, when you're done scraping, you could always bolt your camelback onto the back of the column to strengthen it up :) .

I'm still considering the casting option, but if I was going to go to the trouble of having a casting done, I'd rather just have a whole new column cast. I didn't check, but I'd imagine the foundry that I went to would be able to normalise the casting. For the time-being I'm going to have to get my column into serviceable condition, because it'll have to do for a while yet.

I haven't thought about adding a block to increase y-travel. I've been looking at my ballnuts and I have a feeling that I might run out of space for those if I try and extend the y-travel backwards. I will investigate this further later on today.

Warren

Oldmanandhistoy

09-05-2007, 07:02 AM

Hi,

John, when you're done scraping, you could always bolt your camelback onto the back of the column to strengthen it up :) .

Warren

Lol I did think about that for a second :p :nono:

John

Oldmanandhistoy

09-05-2007, 01:27 PM

Warren,

You might be interested in reading this thread.:D

http://www.cnczone.com/forums/showthread.php?t=43052

John

itsme

09-07-2007, 02:19 AM

John,

Your new method sounds very interesting. It seems as though you are getting excellent results with less effort.

I was at a second hand tool shop yesterday and hanging in the corner, was an electric biax scraper. It was a bit manky and had obviously seen many hours of use. I was very keen to get hold of it (obviously), until I found out the guy wanted £90 for it. Now, maybe £90 is the going price for one of these, but I just couldn't justify it on something that old that looked like it may break down in the not-too-distant future (I don't want a biax scraper restoration project too...).

In the mean time, one of my slides has been roughed flat (by hand) and the other is in progress. It has been easy for me, because my Dad has taken a liking to scraping :) ! How convenient...

I have to replace at least the x-axis gib, but will probably replace them all. I'm thinking about using brass for this. John, do you have to replace any of your gibs and what material are you going to use if you do?

Warren

Oldmanandhistoy

09-07-2007, 05:56 AM

Hi Warren,

Scraping for me is now a joy to do you could say it has become therapeutic. I strongly recommend you give it a try even if it’s just to touch up one of your ways. Just keep the pressure and speed very light. If you do, let me know what you think please. I did go over board on my X-Y saddle and now can not measure the error in the parallelism between the X and Y ways so it is accurate to the extreme (less than +/- 0.002mm).

Having said that I wish I had a power scraper (aka as your dad) all right for some.
I would have balked and walked at that £90 price tag also. It would not have been justifiable at the stag we are at, especially for you as you have your dad doing all the hard work.:p

As for the gib replacements it just so happens that my X axis gib (Y is ok) will need replacing, I did a temporary mod which is working very well but will replace it in due course. Let me know if you would like more info on the mod and I will add details.
Before I make my new gib/s I was going to do a search for the ideal material to use. I have heard of people using brass and was going to look into that also. I presume/believe they are cast iron at the moment? I can see the advantage of using a softer metal than the bearings but am as yet unsure what the ideal would be.

John

Shedaholic

09-12-2007, 06:52 AM

Oldmanandhistoy

09-12-2007, 11:42 AM

Hi all,
Please forgive the shameless 'mine’s bigger than yours’ post:) . Thought you might be interested in seeing how a spare table from the XJ25 model looks on the XJ20 mill. In a word it’s huge, and satisfyingly heavy. Now I’ve just got to give it a clean and bolt the ballscrew on and I’m ready to go although I have tracked down a copy of the Edward Connelly scraping book so might have to give it a quick touch up first. If anyone’s interested in obtaining the book I know that there is at least one other copy available if you put a wanted advert (free) on the homeworkshop.org.uk website. If anyone’s interested in adding a spare table to their mill I bought mine from Hugh at amadeal.co.uk for the princely sum of £45 including postage:).

Steve

Hi Steve,

I think we all know by now that size does not matter its how you use it (ask a woman for an honest answer to that and she would say :bs: ).

As for the table; nice one but will add to the scraping lol good luck with that.

The book you mentioned is a book that I would like to read for research for my own book “Bringing the Art of Scraping into The 21st century” and would be the new bible on the subject pmsl:D . Don’t forget the rule of the scraper lords “do not pass on the knowledge to the common man”. If your interested in selling it once you are finished please let me know.

Would you (or anyone else) by any chance be interested in selling me your X axis screw with both X and Y nuts? If any one is please PM me with a price and I will get back to you if it isn’t too expensive. :)

John

itsme

09-12-2007, 11:47 AM

Hi,

Steve, that table looks like a worthy addition to the machine. How much extra travel does it give?

For the time-being I'm going to stick to the standard table. I don't see myself needing more x-travel any time soon (although there'll surely be something that's too long...), and I certainy don't want to put myself through the trauma of scraping another (even bigger :eek: ) table for at least another year :) . Having said that though, you might get a good one that doesn't need much work.

It seems that you're quite far with your CNC conversion. What ballscrews have you got? I've been looking at how to mount mine, and it seems that the x-axis is going to be OK (with a bit of milling needed on the saddle for clearance), but the y-axis seems quite limited for space. I'm sure I'll fit them in, but it's going to take some thought.

As far as I am concerned, the column on my mill is rubbish/awful and is the weakest link on this mill. I wish I could melt iron at home - simply for the satisfaction of watching my column disappear into a puddle... I still probably have to save it though. What a pity :( . How's yours coming along, John?

Warren

Oldmanandhistoy

09-12-2007, 11:59 AM

As far as I am concerned, the column on my mill is rubbish/awful and is the weakest link on this mill. I wish I could melt iron at home - simply for the satisfaction of watching my column disappear into a puddle... I still probably have to save it though. What a pity :( . How's yours coming along, John?

Hi Warren,

I’ve completed all my scraping (took about 4 hrs to do the column and is straight now) just got the dovetails to lap and I’m good to go. All this scraping might be a long drawn out job but IMVHO it is worth the effort and I would be happy to do it again if I had to.

All in all I am happy with my mill and if I had to buy it again I would. As for the seller; as already said he is first class imo. I think that covers the main subject of this thread so it’s a free for all and I will very probably leave it to you lads.:)

John

AGA-man

09-12-2007, 01:59 PM

Hello John,
Can you give some words of wisdom on what you intend to do with the dovetails? only after reading this I went and bought a XJ12( the smaller one) and overall it looks ok apart from the dovetail on the Y axis where the gib strip runs and this looks very rough and it would be nice to smooth this out .
Steve

Shedaholic

09-12-2007, 04:38 PM

Evening all,
I fully agree that size isn't everything but surely 200ipm with high precision must count for something?;) The bigger table from the XJ25 is 800mm long which gives an overall x travel of 550mm:) . Have to admit that the casting isn't as good as my original though, talking with Hugh at amadeal it seems that the factory has been overwhelmed by orders recently which might reflect some of the problems being discussed around here, my fairly early version of the mill is straight as a die (even if it has plastic gears). I've finished the Z and y axis (used Chinese ballscrews from ebay that were surprisingly accurate) but I'm just waiting for delivery of a brand new x axis ballscrew to complete the set:(. Admittedly there's not a lot of room for the y axis ballscrew, I needed to pocket the saddle and grind half of the nut flange to get it to fit and the x axis requires even more pocketing but at least the z axis is fairly easy (if cramped). Finally, if anyone is thinking of cnc'ing an XJ20 please remember to drill a drain hole in the y axis trough early as guess who had to take everything apart twice to rectify this little ‘Doh’!:violin:
Steve

bpgoa

09-13-2007, 05:06 PM

Hi... sorry to jump in on this thread, but I'm new to the hobby and considering my first mill. I dropped Hugh an email and he pointed me straight here. After going to the model engineer show at Ascot and searching what seems like hundreds of web sites including eBay, i thought i had settled on buying the xj20. That was until i have gotten scared by all this talk about scraping which to me sounds a similar black art to plastering walls. (which i really can't do - I've tried more than once). could i buy this mill, clean it then run it? then work on the scrapey bit later? this leads me to another issue... as i could really do with some help rationalizing my decisions as there seems to be nowhere to learn how to use this