Sieg x1 Mini-Mill

[iceblu3710]

Hello all, ive been a lurker and dreamer for all this time and finally got enough spare room to have some fun. (I kicked out my roommate.)

I have looked at dozens of home-made mills and a whackload of chinese and domestic industrials and decided to buy two mills instead of one.

I am an electrician who in 12-18months will be going to school for electronics engineering and a hobby wood, clock, pcb builder. I originally was looking for a 12x20in xyz machine but decided their way out of my price range at the moment.

I went to Harbor Freight today and bought the x1 mini mill for technically free as I sold a car I fixed for $400 profit, next friday im ordering the cnczone pro 305oz/in stepper kit and my mill will hopefully be shipped (5-10days)

I know its not the most accurate or stable of all the machines but for $300 and as a started machine its great, once im accustomed to mills and cnc ill be able to buy a $1-2k machine, build the mounts and not be horrified of ruining things.

OK onto my questions, but first what I plan to do with my mill:
I will be milling double sided pcb's 1/16-1/32 thick so ill need 0.0015in accuracy on the z axis and my traces are all 8-10mill with 1-5mill spacing so ill need 0.001-0.005 on the xy. I think this is easily attainable as everyone seems to be aiming for 0.0001 accuracy.
I make boxes with dovetail joints out of Ash/Teak/Elder for my nieces and clock faces.
I will be making gears, nothing tiny 0.5in 25tooth is the smallest i go and most are just for looks, this guy does what I want to do (http://video.google.com/videosearch?...en&sitesearch=)
My gears will be out of 22-16guage 6061al/brass or plexi

The prime reason im buying the mill is for pcb's as im starting to come out with 2-3 boards a week and by the time I get them back from the board houses Ive lost interest or changed my designs. With a mill I can build and proto the same day at least.

Questions:
1) bits.. oh god.. Carbide is best but thats all I know, can you recommend some kinds, names links or the gear cutting, pcbs, and plexi? (or a link to learn about bits)
2) I see all these mini vice on the mills but saw none at HF, where do you get them and how much?
3) Is the rebar & concrete in the column and base effective?
4) 305oz/in steppers might have problems with the z axis weight, im going to rig up a strut or weight system regardless so the motor lasts longer.
5) Im planning on putting high resolution encoder wheels on every axis, does MachCNC have necessities to understand these inputs, if so anyone done it and have a tutorial/explination?
6) Where does one buy the guages that show backlash, ive seen them used to measure runoff on lathes and the level of the table axis or is their a better way to figure out my machines accuracy?

Im planning on documenting every single step of this project for my friends and everyone else's benefit but this will take a while as im not the richest man on earth... bear with me please! Thanks!

[jmdelta]

I have a Harbor Freight X1 Mini Mill that I CNC'd and use daily ( in business ) for milling both 6061 Alum and C360 Brass.

I've run it about 5 hours a day for the last 12 months. I spent about 1500.00 total on it (mill, cnc, computer, vises, end mills, drills, parallels, misc).

I love the little machine and it more than earns it keep, however, it does have it's issues.


>I will be milling double sided pcb's 1/16-1/32 thick so ill need 0.0015in accuracy on the z axis and my traces are all 8-10mill with 1-5mill spacing so ill need 0.001-0.005 on the xy. I think this is easily attainable as everyone seems to be aiming for 0.0001 accuracy.

I have .02 in of backlash in all three axis so I don't even try for .0015in accuracy. It is unlikely that you will get .0015 without ball screws and thrust bearings (Balls screws would be a serious overkill on an X1).

Even then, on my mill, the table ways are uneven (slightly hooked) and needed attention to get the table and head to move without binding when you tighten the gibs down.


> 1) bits.. oh god.. Carbide is best but thats all I know, can you recommend some kinds, names links or the gear cutting, pcbs, and plexi? (or a link to learn about bits).

I don't do pcb but if you plan to do any alum or brass:

I use SHARP good quality, Single End, Center Cutting HSS (High Speed Steel) End Mills. Less expensive and with the light cuts you'll be doing, you won't need carbide.

I purchased a 3/8 End Mill Holder and purchase all of my end mills with 3/8 shanks. The largest End Mill I use is 1/2, but take very light cuts.

Don't use the drill chuck for end mills. Get an end mill holder:
http://www.littlemachineshop.com/pro...1705&category=

My mill cuts alum and brass best with 1/4 End Mills taking .2mm cuts. Smaller End Mills seem to clog up and the column has to much flex to do much with the 1/2 End Mills.

The column is difficult to tram (using shims) and I have never been able to get it 100% square to the table so I don't do fly cutting. For the parts I make, a column that is out by .02 - .03 is not an issue.


I get most of my tools at:

Ecno, http://www.use-enco.com
J&L Industrial Supply http://www.jlindustrial.com/cgi/jisrhm
MSC Direct http://www.mscdirect.com/

KBC Tools http://www.kbctools.com

LittleMachineShop http://www.littlemachineshop.com

There are a bunch of others.

A note: Enco, J&L and MSC Direct are owned by the same parent company MSC but have different catalogs. Enco usually has the best prices. MSC is almost always the most expenseive but has a much wider selection.


Request Catalogs from as many tool places as you can. You can spend hours drooling over the tools. :-)



Someone else will need to help you with the PCB stuff.



>2) I see all these mini vice on the mills but saw none at HF, where do you get them and how much?

With the PCB stuff, it may be best to use a jig to support the board while milling instead of just clamping it in a vise.


Enco, KBC Tools and Littlemachineshop have the vises you are talking about.

I paid 50.00 for the first one, 180.00 for a better second one. Get a good vise the first time and get one that pulls the rear jaw down. Also, be sure you don't get a vise that is too large. These mills have a very small working range, about 5x6 inches.

My first vise was similar to this: http://www.littlemachineshop.com/pro...1590&category=



>3) Is the rebar & concrete in the column and base effective?

Never tried it. Could not hurt. There is a LOT of flex in the column on these mills. I'm usually limited to rough cuts .3mm and finish cuts at .05mm in alum and brass.

For milling on PCB boards, I can't see where you would need to do heavy enough cuts to flex the column since the bits you'll be using will be very small. I don't do PCB stuff so I can't say on that.



>4) 305oz/in steppers might have problems with the z axis weight, im going to rig up a strut or weight system regardless so the motor lasts longer.

I used a 4 axis HobbyCnc Pro board with 305 steppers and the Z column does fine with no weight or strut but I spent some time lapping the column ways to make them smoother. Getting the gibs adjusted JUST RIGHT is key. To tight and you get binding, too loose and you get slop. Takes practice.


>5) Im planning on putting high resolution encoder wheels on every axis, does MachCNC have necessities to understand these inputs, if so anyone done it and have a tutorial/explination?

Don't know. I use mach3 but have never had an issue that needed encoders on my mill.


>6) Where does one buy the guages that show backlash, ive seen them used to measure runoff on lathes and the level of the table axis or is their a better way to figure out my machines accuracy?

Enco, KBC Tools, MSC, Littlemachine shop, others.

>Im planning on documenting every single step of this project for my friends and everyone else's benefit but this will take a while as im not the richest man on earth... bear with me please! Thanks![/quote]

Have fun, enjoy.

[Crevice Reamer]

Here are some PCB milling videosn on a Proxon mill that is even smaller than the X1:

http://video.aol.com/video-detail/pr...ing/2067399153

CR.

[darkith]

I have an X1 in the progress of a CNC conversion.

Z axis is definitely a weak point. I'm considering this (http://www.xylotex.com/Counterlever.htm) to "extend" the Z dovetail contact area for better rigidity and less wobble. I don't have a counterweight yet, as with the stock screws it handles okay.

PCB milling and small bit milling needs *high* speeds that the X1 can't even dream of stock. A belt conversion seems to be popular, or adding a second spindle (Proxxon mini dremel-like tool). These is a belt drive kit offered, though the website has disappeared while he transfers it to new hosting. Join the Yahoo group (http://groups.yahoo.com/group/hf47158toCNC_Moderated/) for more good resources.

D.

[Crevice Reamer]

You might be better off to return the X1 and buy an X2. It has both a 20K spindle and a belt drive kit available:

http://littlemachineshop.com/product...2892&category=

CR.

[Crevice Reamer]

This belt conversion for the x2 mini mill brings top speed up to 4300 rpm:

http://littlemachineshop.com/product...2560&category=

CR.

[Crevice Reamer]

OR, maybe THIS mill for $310 would be better suited to the PCB machining:

http://www.carpediemstore.com/listCa...idCategory=312

CR.

[darkith]

Yeah, that's the same grinder I've seen attached to various mills. Wouldn't be hard to build a mount for the X1 I think.

The "Tj-cnc" conversion gave up to 8000 rpm I think...probably still on the low side for PCB cutting I think, but good enough for small bits in aluminum. The replacement bearings were rated for 16k, so it's possible that swapping/replacing the pulleys might give even more speed. IIRC, the stock bearings get warm/hot at 4k, but haven't tried speeding things up yet.

Another high-speed spindle option I saw was the flex shaft from a dremel-like tool mounted in a modified drawbar down the center of the spindle, with the dremel head mounted in a collet. Dremel tool ran the flex shaft while the X1 spindle stayed put. I imagine that the runout of the flex tool head unit could be an issue if it's a sloppy unit.

D.

[iceblu3710]

Thanks for all the input!

I bought the x1 because I live in vancouver and drive a toyota tercel, HF is 90min away and most companies wont ship a mill to canada because of insane freight charges.

I wish I would have gone to the bellingham grizzley showroom To see this but I only have $3-400/month spare cash and when im really into cnc ill go for something along the lines of this or this guy. When ive saved up or made some money with my x1 to rent a truck and garage to store the machine in.

Ill be using the mill for 80% pcb, 15% brash/al 16-22guage, 5% wood/lexan blocks I have a dremel xpr400 and am thinking of either replacing the x1head with it of doing one of those off the the side versions. If i replace the stock head Im sure it will mill wood/lexan blocks but think a dremel can handle sheets of al/brass?

Sounds like the z-axis is flakey on these, Ill mount some nuts in the column when i rebar and concrete it so I can weld up a sturdy a-frame, should get rid of all the column wobble. The extended dovetail seems like a good idea, I haven't seen the shape of them yet but I imagine you could mill your own 4in extension. Im also mounting the vertical shaft a few inch off the base to get full z travel out of the head so adding the extra dovetail would not be noticeable.

Hows the x/y axis on these things? any pointers on getting them better without the 'replace all the parts' ideas, remember I have a pathetic budget currently.

EDIT: I had to order the x1 to the Everett HF store (5-10days), do they allow cancellations with refund, or in store credit, or not at all? Just in case this thread convinced me to buy better.

[darkith]

I'm in a similar boat. In Canada, and prices on X2s are wayyyyy higher here. Think the lowest I saw for an X2 before I bought my X1 was $850. Since then, Busy Bee's has theirs on sale for $678, which would be tempting if I didn't already have the X1 (though I did get the X1 for pretty cheap).

Anyways...
I don't think a Dremel would be rigid enough for an real amount of Alum/Brass. I think there might too much play in the bearings and you'd get chatter, but I might be wrong if the Dremel is higher quality than I think.

The stock X1's Y axis is supposed to be pretty bad, either too loose for accuracy, or too much wooble. The contact area is too small once the table moves out pass the halfway mark. LittleMachineShop sells an extended Y-axis upgrade kit (from the Super X1), which is supposed to be a "must-have", but the cost of shipping it up to Canada makes it a bit expensive. The extended X-table is also popular, and I think gives even more table than an X2, but again, expensive to ship. Adding those mods with shipping brings you into X2 price range.

One option for improving backlash accuracy is to replace the stock iron nuts with delrin nuts, and the gibs with brass. Some good conversion ideas here: http://homepage.ntlworld.com/andy.bi...mill/index.htm
Note that this is the Super X1 with the improved Y-axis and bigger table, so he didn't have those problems to deal with.
I found that even just wet sanding the gibs with very fine sandpaper helped in a pinch, and lapping the ways is also supposed to help.

If I were you and could get to a Busy Bee store (there's one in Vancouver), I'd *really* consider getting their X2 instead. The only real gotcha is that the Z-axis is going to be harder to CNC, as it's a rack-and-pinion, and either needs an ACME screw or ballscrew added. Plus you'd probably have to postpone buying the tooling until your budget recovers, but you'd be able to do much more.
http://busybeetools.ca/cgi-bin/pictu...0&NTITEM=CT133

edit: I do really like my X1, and the smaller size, lighter weight, and affordable shipping are nice. But an X2 at a reasonable price might be a better deal if you can deal with the Z-axis.

D.

[iceblu3710]

Busy Bees version of the mini-mill is $100 more than harbor freight.. and $600 is still twice as much as micro-mill. the proxxon is a good little guy but 2in y travel is almost useless, my eagle license is 100x80mm so thats my minimum travel required.

Im starting to get worried, I was only planning on spending $1000 on this project -bits, tools, material. After the cnc kit, mill, a-frame, concrete, counterweight I have $250 to improve accuracy. if I need to spend over $400 to get it within x2 accuracy I might as well just buy that. The grizzly G8689 is the x2 and $523 but that ballskrew kit is $250 so I wont have a full cnc untill Sept by the earliest.

The upside of the x1 is I could have it running by end of the month, no more sending my pcb's off to china to get manufactured for $40/pop. Do you think resale would be decent enough, would you guys pay $500 for the x2 with 305oz/in hobbycnc when I want to upgrade like next year?

[hoss2006]

I don't think you would have a problem selling it.
Have you tried looking for a used one yourself?
Probably hard to come by.
It's like when you buy that new big screen TV, you keep the old one
and just put it in the rumpus room.
There are probably plenty of mills out there people just don't want to give up.
Besides, you can use the old one to help upgrade the new one later on.