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KyleH2
06-04-2008, 07:15 PM
Ive spent the last hour or two looking for build information on CNC Knee Mill conversions. From a manual Bridgeport-like knee mill to a 3 axis CNC mill.

My budget: $10,000 for the mill ready to go, but not including all tooling.

What I want it for: Making auto racing parts to sell in my eBay store. (All my parts are currently made in China.) I am leaning towards this 2HP model as most parts I plan to make out of aluminum or mild steel and it has a little higher RPM rating than its 3HP counterpart. I will be using this to help make money to put me through college.

What I want it to be able to do: Make perfectly round circle interps, not chatter/shake and be able to take more than a .050 DOC. Optimally I'd like to put 2 or 3 parts on a fixture and run them over and over saving setup time.

My training: I am 19 but I have my OCP A-D (Full machinist certs), taught myself how to work on cars starting at 15 and am going to college for mechanical engineering. I posted here as MidFloridaTech briefly.

What I want to do exactly: I want to buy THIS (http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=38850) harbor freight mill and convert it to CNC. I will make the brackets on it and a 13x40 lathe I plan to also purchase from HF. I will be running it off my laptop or will build a PC for it and use the Mach controller everyone else seems to use.

What I need to know:
1) I need thread that details with pictures a knee mill being converted. All the ones I saw had been taken down, pictures lost, etc. VERY FRUSTRATING!
2) I need to know if the off the shelf ball screw kits and retrofit guides you can get for a Bridgeport will be exactly the same for this mill. Is this mill an exact clone with interchangeable parts? Will the ball screws work?
3) What are my options for fighting backlash? Do I need to worry about it much with a brand new machine (this question also could be asked as, do I have to buy ball screws for it?)

Why don't you buy a BP Boss, older BP and convert it, older CNC mill or Tormach? while I have considered those, it would be difficult and expensive to hire a company to transport it here. I could buy an older bridgeport locally but the cost for a decent one usually is less than a $1000 difference between one from the 1970s and this brand new HF unit. Older CNCs might have things go wrong with them and I wouldn't know enough about them to fix them, then there is the issue of parts. Plus the issue of getting them here. The Tormach has less travel, less table, less power, etc. Its an option, but if this is possible obviously it would be much better for light production like I am talking about.

EDIT:

Just found this:

http://www.cncmasters.com/CNC%20Supra%20Knee%20Mill.htm

That seems to be in my price range. Any info on it?

jeep534
06-05-2008, 02:43 AM
This is my opinion and mine alone. if you are going to do any type of production and.. are concidering a retrofit. you do not want a Bridgeprot Manual machine to convert to CNC. the issue is rigidity and repeatability. any Boss type machine can be converted with much less headache than trying to convert from a standard Knee Mill. and will be a ton more rigid. all the Ballscrews and limit switches ect are already there hooked up and working. you keep saying "get It Here" where Is here.

If the prospect of getting a boss machine and converting it is Intimidating to you then buy the converted machine you linked to. the boss style machine are out there. the other issue is time the longer it takes to get up and running the longer you are not making parts. the older boss machine had steppers and can be converted to run Mach3 quite easily.

I am doing a later servo machine which is a little more complicated....... but much less complicated than doing a full conversion from a knee mill.

also have you looked t the route 66 mills (they have a Knee mill conversion kit and conveted knee mills as well.

Just My 2 cents worth.
the bottom line is you want to do production of many like parts. weight and rigidity is your friend. now that being said the one thing you have overlooked about the tormach is it has a tool changer I believe.

a friend once told me that a cnc knee mill is 3 times faster than a Manual one and a machining center is 3 times faster than a cnc knee mill because of the tool changer. just something to think about.

Happy Hunting
archie =) =) =)

KyleH2
06-05-2008, 02:58 PM
Another issue I have with buying an older machine is that I dont know that I have the knowledge to evaluate its condition. I am worried that I will purchase one and of some unknown reason it wont work or it will cost a lot to get it into fully functioning condition.

The HF mill I posted is 2600lbs, so it seem the weight is therem, but what makes you think it wouldn't be rigid? Along the same line what exactly one knee mill of comparable weight and design more rigid than the next?

I can buy the tormach's tooling system and use it in any R8 spindle if I want to improve productivity that was and have the cash. It bothers the heck out of me when companies dont list the prices of thier machines. I dont want to email you for a quote. I want to compare you directly with your competitiors quickly and easily.

That said the route 66 #4 looks like a pretty sweet (and I am sure out of my price range) machine. It says it has a #40 spindle motor. Do they mean it uses CAT-40 tools?

jeep534
06-05-2008, 04:27 PM
Another issue I have with buying an older machine is that I dont know that I have the knowledge to evaluate its condition. I am worried that I will purchase one and of some unknown reason it wont work or it will cost a lot to get it into fully functioning condition.

The HF mill I posted is 2600lbs, so it seem the weight is therem, but what makes you think it wouldn't be rigid? Along the same line what exactly one knee mill of comparable weight and design more rigid than the next?

I can buy the tormach's tooling system and use it in any R8 spindle if I want to improve productivity that was and have the cash. It bothers the heck out of me when companies dont list the prices of thier machines. I dont want to email you for a quote. I want to compare you directly with your competitiors quickly and easily.

That said the route 66 #4 looks like a pretty sweet (and I am sure out of my price range) machine. It says it has a #40 spindle motor. Do they mean it uses CAT-40 tools?

Kyle, first of all what part of the country do you live it really does make a difference what might be available.
Point one HF at the risk of being rude it is junk for any type of production cnc work.

There are many reasons to recommend a Boss style of machine.
1 If you buy the HF machine You will have problems cncing the z axis
2 a lot of people cnc the Knee instead
3 the leadscrews will have to be replaced with ball screws and fit home and limit switches.
4 does the mill you are buying have a one shot lube
5 all in all it will cost 3 to 4 thousand to retro the "new" hf mill.

and it still will not be a production machine.

You should be able to find a non functiioning bridgeport style machine 1000 to 1500 dollars or less. I gave 400 for the lagun. and the retrofit will cost less than trying to reinvent the wheel with the HF Mill

I have just finished updating my web site

http://jeep534.smugmug.com/Hobbies
look at the retrofit pictures real close.
I am working out of town and am at a standstill right now except working on my web site =-(

it is your time and money
it is said we spend what we have sometimes it is time and sometimes it is money. and sometimes both.

as for 40 taper that is not cat40 it is probably NMTB40 like my machines are I have NMTB 30 40 and now 50

I do not know what else to say, if you want a nice hobby manual mill the hf might be ok. but it was never meant to be cnc'ed. they are two different animals..... designed much different

Happy Hunting
archie =) =) =)

DareBee
06-05-2008, 04:35 PM
#40 taper is a #40 taper is a #40 taper. The difference is the holding method. Am ISA 40 has a stem and is meant for use with a drawbar. A Cat 40 is American with inch threads and slightly different flange that fits the ATC. BT 40 is Japanese has metric threads and different flange for the ATC.
The machine you look at above will be ISA 40.
40 taper is way more rigid than R8 and facilitates having tools preset for length.
If you are wanting to do PRODUCTION and want to make the most money you can per part you need a REAL VMC with ATC and rigid tapping (if tapping any holes). A standard kneemills ways are not designed for CNC production work and will wear out quickly. I would never consider production work without an enclosure and high volume coolant system as well.

IMO you should be looking for some sort of mini VMC. They start new at under 40k or for cheap - get something like the Tormach or Syil Super X4 and build an enclosure.

KyleH2
06-05-2008, 06:06 PM
Thanks for the replies!


Kyle, first of all what part of the country do you live it really does make a difference what might be available.


I am located in Orlando, FL.


and it still will not be a production machine.

The "production" I am doing is a joke compared to "real" production. What qualities and capabilities do you say make up a production machine? For me its basic repeatability (ability to swap out billets of material and keeping things bolted to a fixture) to run average speeds and feeds (I know it wont really get up to the RPM I want but oh well.)


You should be able to find a non functiioning bridgeport style machine 1000 to 1500 dollars or less. I gave 400 for the lagun. and the retrofit will cost less than trying to reinvent the wheel with the HF Mill

What was wrong with the Lagun? You would suggest looking for a machine with a bad controller? How much will it cost you to retrofit it? How do you know whats wrong with it and where did you get the information on retrofitting it?


#40 taper is a #40 taper is a #40 taper. The difference is the holding method. Am ISA 40 has a stem and is meant for use with a drawbar. A Cat 40 is American with inch threads and slightly different flange that fits the ATC. BT 40 is Japanese has metric threads and different flange for the ATC.

Wow that just cleared up so much for me. So I can buy any #40 tapered holder and just change the little piece that threads into the top of it?



If you are wanting to do PRODUCTION and want to make the most money you can per part you need a REAL VMC with ATC and rigid tapping (if tapping any holes).

I don't want to do real "production" per se. I will only be doing this for 3-4 years more through college. I want to make some parts to sell on eBay and I want to keep the mill after that to do things related to engineering and hobbies. I am currently a freshman going for a Mechanical Engineering degree.

Al_The_Man
06-05-2008, 06:32 PM
Most points have been covered, I would just like to add a bit to what is already said.
If you are concerned about retro-fitting, you need virtually the same knowledge and ability to convert a manual machine.
As has been said, the mechanics, ballscrews etc are already on.
The thing to bone up on is how to tell if the mechanics are still in good shape, look at way wear, and take a dial gauge if possible and do a simple backlash test, in most cases this can often be done without power.
The machine will have disconnects, contactors and power supplies and enclosure that generally can be reused
There used to be an excellent site on a quick course on assessing a used machine, but it seems to have disappeared, If I find it I will post it here.
Another thing is what power do you have and what do you need, most larger mills like bed mills will run under a RPC (rotary phase convertor off 240 1 phase) to obtain the 3 phase.
I would not consider retrofitting a knee mill and CNC'ing the knee, not if you want fairly good production rates or are considering peck drilling.
If looking at knee mills, the XLO Exello Ram Mill is considered by most, more rigid than the BP. There are a few out there that were converted to production, they have a Z quill and often power knee for rapid initial knee positioning.
Al.

KyleH2
06-05-2008, 07:44 PM
Any suggestion to helping me find one in my area? I currently have an RSS feed from ebay and Orlando Craigslist that alerts me anytime any type of machinery for metalworking gets posted within 50 or 75 miles.


There used to be an excellent site on a quick course on assessing a used machine, but it seems to have disappeared, If I find it I will post it here.
Another thing is what power do you have and what do you need, most larger mills like bed mills will run under a RPC (rotary phase convertor off 240 1 phase) to obtain the 3 phase.

Please post it if you can find it. I have 220V single phase. This is going in a regular household garage. Whatever I get will either have to run on a 3-1 converter or would have a single phase motor.

blackdoggy
06-05-2008, 07:59 PM
Hunt online and at your local industrial auctions for Bridgeport's 98% of anything with the HF name on it is trash. One of the machine companies I have been looking at for retrofitting my 49 Bridgeport would cost me around 6 or 7K shipped to me then maybe another 1 or 2 to clean it up and put some new bearing in.

MrWild
06-05-2008, 08:22 PM
I bought a Boss Bridgeport for peanuts. It had been retrofited with a "new" control sometime around 94 with servos and all sorts of goodies. Because I didn't know what I was looking at, the bunger got inserted hard and deep. The ways were "ok" but the head was trash and the ballscrews were junk. I lost money getting rid of it and buying something newer, and with much less wear. I'm fairly happy now mechanically. It'd be nice to have a new control, but not needed, and I've amassed the parts to upgrade the control to EMC2 with MESA Electronics control boards.

You are right to be wary, but you really need to make sure to get box ways, and a machine that is already CNC. There are still some very low hour pristeen examples Tech colleges are parting with. The right one would be worth the shipping expense across country. You wion't be happy at all with the HF example down the road. New junk is still junk. Sometimes just because you can and know how to do something, doesn't mean you should.

KyleH2
06-05-2008, 08:28 PM
Everyone talks about what crap tools that HF has. I can honestly say that 90% of their stuff that I have bought have worked great. The stuff that didn't I returned with no problems and was stuff I suspected of being crap. Like their cordless electric stuff. That is neither here nor there. Their mills aren't made by them, they are likely made by a major Chinese manufacturer and probably the same as the larger grizzlies.

It is probably worth mentioning that I probably will not ever need to hold more than +/- .001 on any dimension. Probably wont even need to hold that. I am talking about building cosmetic parts, and stuff thats going to get welded on or bolted together.

If I want a small machine to hold +/- .0001 on I would take up Gosinger's 4.9% offer on a Hurco VM1 Mill or TM6 Lathe. But they cost $30-40K + interest, and although they're great machines and I enjoyed using them both at tech school, I can't afford one as part of a business plan.

This machine cant be one that takes a year of 12 hours a day of operation to pay itself off. If it is I don't need it, I will get my parts manufactured overseas rather than make them myself.

I have read a little bit about what box ways are, but what machines do not have box ways?

I would love to have either of the mills my local tech school does. But the only way that is happening is if the school shuts down.

blackdoggy
06-05-2008, 09:34 PM
Instead of doing it your self and buying machinery or shipping it over to China why not get one of us to do it for you? Most every one here has modern machinery and most can run circles around the Chinese. I give you credit for having the skills and desire for your own equipment but if some one else has everything and can do it better, cheaper, and faster than China why do it yourself or ship it? You still need to understand any machine you get even something as old as I have still needs to generate enough product to keep you fed. If you take chances with Chinese machines chances are you might end up eating dinty moore instead of eating steak., You run less risk using older brand name American machines than China discount brand I mean can you call up HF and get a part in less than a week where as if you need most any part for a Bridgeport you can have it in your hand the next day.

KyleH2
06-05-2008, 11:06 PM
Instead of doing it your self and buying machinery or shipping it over to China why not get one of us to do it for you? Most every one here has modern machinery and most can run circles around the Chinese.

If I could get the machined items produced here cheaper than there I would do it in a heartbeat. I would probably still buy the welded items from there because they do a great job for a great price no American welder could beat it. ( For example an intercooler core retails for more than the cost of a finished intercooler at my cot including getting ti here and tariffs) And thats at the cheapest core prices I have seen.

I would still get a machine though. I love machining. (My own stuff. I would hate changing oil or machining some company's parts on that company's machines.) I am not a point dexter calculus student type of mechanical engineer. I am the type that likes designing things, building things, and also maintains a high GPA. Why not get a machine that can make some money in the process?

I might just put out an RFQ though as I am about ready to buy some more of a particular simple-to-machine item. Well see if some of you guys can't compete with the Chinese.


EDIT: By the way on a funny side note, it has shocked me in college how little any of the students understand about manufacturing. Out of 20 or so people I have talked to, all majoring in engineering in mechanical or aeronautical, most are second year students, not one has known what a lathe was. When I described how it worked (I guess I did a poor job of it) they asked if it was like a particle accelerator. I know its not really required to be an engineer but it seems pretty related to me. :confused:

blackdoggy
06-05-2008, 11:29 PM
Another reason you might try to have it machined by someone here is the Made In USA sticker will usually allow a slightly higher cost of any said product. It's pretty sad when a student in the engineering field can't identify or understand what a lathe is, I mean how can they spec a part with out knowing what it is to be made with or on:confused:(chair).

KyleH2
06-06-2008, 01:12 AM
haha and its not like they were comp engineers or sanitation engineers. Its freaking MECHANICAL engineers. I put up an RFQ for one of the parts I want made. Lets see if we cant strike up a mutually beneficial relationship.

Caprirs
06-06-2008, 01:58 AM
Another issue I have with buying an older machine is that I dont know that I have the knowledge to evaluate its condition. I am worried that I will purchase one and of some unknown reason it wont work or it will cost a lot to get it into fully functioning condition.

If you are concerned about your ability to troubleshoot, then performing an entire retrofit might be a little too much to bite off yet. I don't mean that in an insulting way. Since you're familiar with cars, the analogy would be you are willing to fab, install, and tune a turbo kit on a car yet you're not sure you can diagnose driveabilty issues. On the other hand, that's how you learn.

You mention wanting something rigid, yet are considering anything from Harbor Freight. Although there are a zillion brands using the same casting, it's the other bits like ball screws, bearings, turcite coated gibs, etc. that make a huge difference in quality.

I have a BSME and have resorted to being a machinist on my own after eight years of "engineering". I spent a lot of time sitting in staff meetings, generating paperwork, writing procedures, supervising, and other dull activities.

I would not consider a knee mill personally (and didn't when I bought my two mills). A VMC with tool changer, flood coolant, and enclosure is not much difference in price, but the capabilities are in a different world. The only penalty is travels compared to the knee mill.

KyleH2
06-06-2008, 02:13 AM
If you are concerned about your ability to troubleshoot, then performing an entire retrofit might be a little too much to bite off yet. I don't mean that in an insulting way. Since you're familiar with cars, the analogy would be you are willing to fab, install, and tune a turbo kit on a car yet you're not sure you can diagnose driveabilty issues. On the other hand, that's how you learn.


haha funny you mention that because I did EXACTLY that at 17 but with a supercharger on a Lincoln Mark VIII. Thats how I learn :P (I joke that it would go faster than the 150+mph I pushed it too, but my balls, would not.)

I see what you mean but I have used, for example, a Sharp mill. At $7000 it was way better than ANY of the Bridgeport mills in the shop. It just overall felt better and was smoother and was easier to make good parts on. It was about 1 year old where as the newest Bridgeport was maybe 10 years old or so. Still it was probably half the price. The reason for saying this is it seems to me that a new machine that I can take apart clean and know that it has been properly maintained would be better than a 10 year old (or older) vmc that someone does'nt want or cant make money with anymore.

To keep the car analogy, while a 2008 Kia might still have less features, it will probably be more reliable than a 10 year old BMW.

I hope no one thinks I am being stubborn, arguing is just my way of encouraging more advice, new ideas, etc.

Caprirs
06-06-2008, 02:44 AM
We sold my wife's Mark VIII a couple years ago. Great car except for the air bags. Never modded it. When we want to go fast, we jump in the Mustang or Capri.

The reliability factor is quite the variable. When the Kia (the car, not the machine tool) starts to become unreliable, it goes to the crusher. When the BMW acts up, you fix it. A broken VMC is worth more than a broken knee mill.

That Sharp will wear faster than the higher quality machine. Thus, a 5 year old Sharp might be as "old" as the 10 year old Bridgeport. The cheaper machine is cheaper usually because the ballscrews are cheaper, the bearings are cheaper, the ways are not as well ground. Some machines are more prone to rust than others as well. In Florida, it seems everything must be awash in WD40 to avert the corrosion.

A lot broken machines that are for sale are on the market because most machininsts cannot or will not fix them. Often, the trouble is electrical and machininsts are notoriously unsavvy about chasing electrical issues. However, most all manufacturers support their machines even after 10 years. Some parts may be expensive, but the payoff is how productive the machine can be.

jeep534
06-06-2008, 02:45 AM
haha funny you mention that because I did EXACTLY that at 17 but with a supercharger on a Lincoln Mark VIII. Thats how I learn :P (I joke that it would go faster than the 150+mph I pushed it too, but my balls, would not.)

I see what you mean but I have used, for example, a Sharp mill. At $7000 it was way better than ANY of the Bridgeport mills in the shop. It just overall felt better and was smoother and was easier to make good parts on. It was about 1 year old where as the newest Bridgeport was maybe 10 years old or so. Still it was probably half the price. The reason for saying this is it seems to me that a new machine that I can take apart clean and know that it has been properly maintained would be better than a 10 year old (or older) vmc that someone does'nt want or cant make money with anymore.

To keep the car analogy, while a 2008 Kia might still have less features, it will probably be more reliable than a 10 year old BMW.

I hope no one thinks I am being stubborn, arguing is just my way of encouraging more advice, new ideas, etc.

Kyle,
the 15 year old boss style machines..... are a much different animal than a Bridgeport knee mil. you asked for our advice an it has been given.

Ballscrews to retrofit the HF mill will cost what you would pay for for a whole machine.
most of the older cnc machine are not running because the electronics quit working because of fatigue vibration ect.

My Mill has preshureized lubricant on the ways and the ways are Chrome. the mill would not run without lubricant.

so It is in real good shape.

Most of all cnc machines whicch don't run have electronic trouble (which would be fixed by the retrofit) or maybe thrust washers on the ends of the ballscrews.

all the rest of it will most likley be ok.

sometimes You have to just pay your money and take your chances.

as for 30 40 and 50 taper the styles are not interchangeable as someone previously pested. you need the corrct one for your mill and there are a few flovors.

al the man made a good point you are talking about retrofitting a machine but are worried about retrofitting a machine that has most of the work done for you......

I think you need to buy something and ask specific questions about that machine.

In a year or two you will look back and say now why did I do that =-)

archie =) =) =)

skullworks
06-07-2008, 12:26 AM
Something to think twice about.

Ask around, ask anyone.

If you need a replacement part for a Harbor Freight branded machine can you get that part and how long will it take?

Manufacture support is a major concern when a business looks to aquire machine tools for production. The true cost of downtime is rarely completely counted but its more than you might think.

If you think the Tormach is too small look at a IH.

Buying all the components and doing your own retrofit will likely take over a year before it is fully up and running and the kinks worked out. This kinda makes sense for a hobby class tabletop machine as until the last few years turnkey units just were not easily available.

Edit: That other CNC Knee mill for about $10K with steppers... 50 IPM rapids - The speed of a glacier in mid summer. Please get real. ( Even the Tormach stomps that number.)

Personally I would look for a not too abused "Tupperware" Haas VF0. Also figure 10% of your profits need to go into a interest account to be ready for those costly (never at the right time) repairs that will happen, and happen more often than you expect. Edit: the Basic VF0 has 20" X axis travel, just a bit more than a Tormach, but only 66% of the IH which has 30" - But ATC, 7500rpm spindle and true Flood coolant are REAL big reasons.

Also hiring an expert to test out a prospective used machine at say $300/hr can be worth every penny.

blackdoggy
06-07-2008, 08:57 AM
The local machinery dealer here has a Bridgeport with a jet power feed and digital read out for 4K (they are in Roanoke Va.), one of the companies I was looking at for retrofitting would be another 5K and that would run all axises with CNC programing. So you figure for that type of money you have a 50-100K machine for 9K thats virtually new and can do most anything.

DareBee
06-07-2008, 10:39 AM
#40 taper is a #40 taper is a #40 taper. The difference is the holding method. Am ISA 40 has a stem and is meant for use with a drawbar. A Cat 40 is American with inch threads and slightly different flange that fits the ATC. BT 40 is Japanese has metric threads and different flange for the ATC.

Wow that just cleared up so much for me. So I can buy any #40 tapered holder and just change the little piece that threads into the top of it?

Contrary to what the guy above said, my statement is CORRECT. The tapers are identical. I will expand.
A machine with an ISA (NMTB) taper will use ANY 40 taper holder with a separate drawbar for the metric BT. My TOS boring mill uses ALL 3 types of holders with my custom made pull studs, this mill is designed to use an ISA type. A machine designed for CAT or BT will NOT use an ISA because of the extra straight section on the end. MY FADAL VMC will use both CAT and BT however the ATC is tooled for CAT and will not use BT without changing all the tool clips in it.


If I want a small machine to hold +/- .0001 on I would take up Gosinger's 4.9% offer on a Hurco VM1 Mill or TM6 Lathe. But they cost $30-40K + interest, and although they're great machines and I enjoyed using them both at tech school, I can't afford one as part of a business plan.

This machine will not make parts to .0001 you will need to add a 1 in front of the price to get into that range of precision.


EDIT: By the way on a funny side note, it has shocked me in college how little any of the students understand about manufacturing. Out of 20 or so people I have talked to, all majoring in engineering in mechanical or aeronautical, most are second year students, not one has known what a lathe was. When I described how it worked (I guess I did a poor job of it) they asked if it was like a particle accelerator. I know its not really required to be an engineer but it seems pretty related to me.

This is very true and not so funny. Some engineers I have to deal with want the most retarded things made that cost a fortune due to "lack of knowledge".
I feel all engineers should be required to complete a metalworking apprenticeship before being let loose on society.
You are a minority with your current abilities, keep up the good work.

HuFlungDung
06-07-2008, 03:40 PM
What I want it to be able to do: Make perfectly round circle interps

This is probably out of the league of cheaper box way machines and shop done retrofits altogether. But, if you want to bore the critical holes in your parts with a boring head, you can still succeed. Depends how many different sizes you might have on one job :)

My older Shizouka retrofit, which so far as I can tell, is not worn out by any stretch, takes some coddling to hold .0005" across linear dimensions, and circular interpolation is probably at least that wavy in every quadrant.

jeep534
06-07-2008, 04:24 PM
I was warned about chasing thousandths when I got started in this machining thing. :)

happy hunting
archie =) =) =)

KyleH2
06-07-2008, 10:26 PM
eBay Link (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=260249022695)

What do you guys think of this? Good deal? I was thinking if I was ready to buy/convert a damaged machine (which I am obviously too ignorant at this point to do) I might call him up and say hey if its in decent shape like you say I'll come pick it up in two days for $3500 and haggle from there. Sound like a decent idea? What do you think of that mill, should that be more of what I am looking for?

To convert this, what would I need to do, just rip out the old electronics, call up Mach Motion, and get a quote for a conversion kit? A link to the FAQs of VMC converting would be great. If I paid $4000 for this do you think I could get it converted then up and running for under 11K + tooling? Under 10K plus tooling? If so then I think this would be the avenue for me.

skullworks
06-07-2008, 10:41 PM
Since your budget is in the 10k range I'd buy the machine and get the Factory or aftermarket memory board - that will cost $2-3K for the fix.

These machines do not run step/direction like "Hobby" class machines. Switching to Mach will cripple the machine and only let you use 25% of its true potential.

It is a great buy - a shop up the street from me has one.

(I use a much bigger Mori Seiki myself, SV50B 40x20x20) :)

KyleH2
06-07-2008, 10:53 PM
So a mach would not be able to run it at its potential? Why is that? Should I still convert it to a PC based controller? What are my options as far as repairing it?

I could replace the main boards inside the controller with factory/after market ones. How do I go about finding them? Do they usually stock them for 20 year old machines?
What else?

At what price would that still be a "great" buy versus an ok one?


Out of curiosity is this:
http://www.machmotion.com/pdf/Mach3%20Setup%20Guide.pdf

All it takes to install a mach motion controller? It looks so simple it makes me wonder if thats really all there is to it. Just clamp a few wires down and youre good to go?


Thanks for answering my plethora of questions, I am quite excited to learn more. If any of this is covered in a sticky or FAQ somewhere, feel free to link me rather than typing it all out.

skullworks
06-07-2008, 11:45 PM
Mach is a Windows based Step/Direction G-Code interpreter. It runs Open loop - meaning it keeps count of the pulse commands it has issued and assumes the machine is following those commands. Open loop on a machine this size and speed would scare me. Been working on CNC's nearly 25yrs and I have all my fingers and other body parts intact and without injury due to a healthy paranoia when it comes to machines.

Problems:

1} The Servo amps in this machine are likely high voltage DC for Brushed servos - (based on the year model) These will likely require +/- 10V Analog Velocity commands - NOT STEPS.

2} Mach has not figured out Rigid tapping - the required feedback isn't there.

3} If you were to use some form of step to 10V adaptor it is likely that the encoder count / pulse stream I/O from Mach will not be able to support the machies true speed potential. IE 787.4 IPM rapids

Your best bet if you want to gut the Yaznaq and switch to PC based would be to get a Mesa 5i20 and 7i33 (digital to +/- 10V) (http://www.mesanet.com/motioncardinfo.html) and run EMC2 (http://www.linuxcnc.org/). You won't be sorry about that choice. This uses all the installed hardware basically as is - you just need to rig up the control panel (same problems as with Mach)

Need more info on EMC drop in the IRC channel.

KyleH2
06-08-2008, 01:11 AM
Mach is a Windows based Step/Direction G-Code interpreter. It runs Open loop - meaning it keeps count of the pulse commands it has issued and assumes the machine is following those commands. Open loop on a machine this size and speed would scare me. Been working on CNC's nearly 25yrs and I have all my fingers and other body parts intact and without injury due to a healthy paranoia when it comes to machines.

Problems:

1} The Servo amps in this machine are likely high voltage DC for Brushed servos - (based on the year model) These will likely require +/- 10V Analog Velocity commands - NOT STEPS.

2} Mach has not figured out Rigid tapping - the required feedback isn't there.

3} If you were to use some form of step to 10V adaptor it is likely that the encoder count / pulse stream I/O from Mach will not be able to support the machies true speed potential. IE 787.4 IPM rapids

Your best bet if you want to gut the Yaznaq and switch to PC based would be to get a Mesa 5i20 and 7i33 (digital to +/- 10V) (http://www.mesanet.com/motioncardinfo.html) and run EMC2 (http://www.linuxcnc.org/). You won't be sorry about that choice. This uses all the installed hardware basically as is - you just need to rig up the control panel (same problems as with Mach)

Need more info on EMC drop in the IRC channel.


If I am going to invest the time and cost into a VMC I for sure want the full rapid speed. Going through that website I see the "5I20 FPGA based PCI Anything I/O card" and the "7I33/7I33T Quad Analog servo interface" which is what it sounds like you're saying I need but I don't see prices. Have a rough estimate of what they would cost?

When reading the description of the cards, how through of an understanding should I have?

Is this correct: The 5I20 sends a signal to the 7I33. The 7I33 then converts it to a +/- 10V signal and is connected to something called a servo amp which I assume is already in the machine and I would reuse it. The 5I20 goes inside my computer in a PCI slot and the software you suggested will recognize/send data from that card. 50 pin connectors (sold separately?) are used to link the 5I20 and the 7I33 and the &I33 to the servo amp.

I have only been doing this two years and yesterday I got 7 stitches taken out of my thumb. First and hopefully last injury.

skullworks
06-08-2008, 01:34 AM
The link I gave you was to the contents of a HTML frame - so you didn't see the pricelist link on the left. However the link at the bottom would have jumped you out of the frame and back to the home page. Sorry - my bad.

Here is the home page for Mesa Electronics (http://www.mesanet.com/).

You have the basic idea as you stated above - you would also add another breakout board from the 5i20 for Misc functions, tool changer I/O, coolant on/off, VFD control, MPG handle wheel input, way lube pump, etc

Every retrofit is a bit different, depending on the options the machine came with. EMC is free and there are people willing to help guide you thru the process. But before I start with the wire cutters I would fax the Error codes to Mori Seiki and find out what the cost of the memory board repair is. Using the OEM Yaznaq will mean the Operator consol works as is, as intended.

I would use EMC if the Control is truely dead to the point that repair is cost prohibative compared to the retrofit cost. - Don't forget to count the cost of downtime for the retrofit vrs a few hours to swap out memory boards.

jeep534
06-08-2008, 03:26 AM
Mach is a Windows based Step/Direction G-Code interpreter. It runs Open loop - meaning it keeps count of the pulse commands it has issued and assumes the machine is following those commands. Open loop on a machine this size and speed would scare me. Been working on CNC's nearly 25yrs and I have all my fingers and other body parts intact and without injury due to a healthy paranoia when it comes to machines.

Problems:

1} The Servo amps in this machine are likely high voltage DC for Brushed servos - (based on the year model) These will likely require +/- 10V Analog Velocity commands - NOT STEPS.

2} Mach has not figured out Rigid tapping - the required feedback isn't there.

3} If you were to use some form of step to 10V adaptor it is likely that the encoder count / pulse stream I/O from Mach will not be able to support the machies true speed potential. IE 787.4 IPM rapids

Your best bet if you want to gut the Yaznaq and switch to PC based would be to get a Mesa 5i20 and 7i33 (digital to +/- 10V) (http://www.mesanet.com/motioncardinfo.html) and run EMC2 (http://www.linuxcnc.org/). You won't be sorry about that choice. This uses all the installed hardware basically as is - you just need to rig up the control panel (same problems as with Mach)

Need more info on EMC drop in the IRC channel.

actually your assertions are only partially correct.
Mach 3 Has been ported to run on the Galil motion control cards which do the voltage thing and not the step thing. and I do believe they close the loop as well. I am not planning to use one so I quit looking at them some time ago.

also the just out smooth stepper will allow tac feedback from a spindle to facilitate threading on a lathe and most probably Rigid tapping or at the very least semi-rigid tapping with a floating tap holder on the mill and has a high frequency connection to the servo amps (by bypassing the printer ports)
http://www.warp9td.com/

there are also people who are running tool changers and live tooling on lathes with mach3 and driving PLC's with it.



However, all retrofits take time and fiddling even the "packaged" ones

If that Mill he is looking at can be made to run as is, that would be the way to go. a little programming in a cam package and away we go.

maybe after a year or two he can afford a hurco or similar VMC

Bottom line, i have been following Mach3 since 2004 and It is maturing very quickly. with the smooth stepper and the larkin Viper drives coming on line that Is opening up a whole nother class of machines to be used in small shops and garages to run a ton of parts and not break the bank while someone who is new to cnc to learn how it all works and why that New VMC is worth 50 to a hundred thousand dollars

Just my thoughts
Happy Hunting
archie =) =) =)

skullworks
06-08-2008, 04:21 AM
Smoothstepper is an improvement that moved the stepgen outside of the PC to get past Kernal speed limitations for a stable pulse stream. But its USB and will have to go thru a few more generations and get alot smarter (doing functions that are still done in the PC) before it will be ready for Rigid tapping.

Had they done it using ethernet like the GRex I might have more respect for it - But I don't trust USB. I went to work for a U.S. Computer corp for a few years that gave me a Criterion chair, air conditioning, free coffee and the heaviest thing I had to lift was a mouse while paying me more than I could dream of in a machine shop workplace. I watched as USB came up - and know not to trust it.

1394, ethernet - both are better - but USB is cheap, and fools insist on trying to run CNC interpreters from laptops so they need a USB interface.

I also know that Mach works as a front end for Galil motion cards, but the source for Mach or the Galil firmware won't be open source so you will likely have to pay for any custom changes you need, if you can get it done. Also Galil wants there people to install the hardware which can get quite costly.

I never said Mach could not work with VFD, or PLC's. Mach's helper macros are very powerful.

Having a few MCP's when my job went overseas, I had had enough of M$ B$ (having to support Windows ME for its life cycle would make anyone feel this way). I use Win 2K to run Solidworks and other CAD/CAM apps as it is very stabile with the right hardware. I just don't use it for real motion.

Al_The_Man
06-08-2008, 11:26 AM
Kyle You have received a lot of valuable advice so far, As some one who has done retro-fits for a living for some years, the Mori.S on ebay in that condition would be a good way for you to go, you should be able to restore it for less than a retro-fit on a less viable machine. Mechanically, it should be in fine shape.
Converting it to an open loop system, IMHO will be a backward step.
Also I would like a buck for every customer I have had that has waved the latest mag article on PC based retrofits that give the impression that you wheel a PC up to the machine and hook up a few wires and Bingo, you have a retro'd machine in a couple of day. It never works out that way.:nono:
One thing to make sure of with purchasing used machinery, often overlooked, is obtain all the documentation, including all machine parameters etc.
Al.

KyleH2
06-08-2008, 12:08 PM
It seems the more answers I get the more questions I have. Thanks!



Converting it to an open loop system, IMHO will be a backward step.


An open loop system is a system that uses steppers and assumes that the machine moved because it said so, correct? Anything that uses servos would be closed loop because it requires feedback, correct?



Also I would like a buck for every customer I have had that has waved the latest mag article on PC based retrofits that give the impression that you wheel a PC up to the machine and hook up a few wires and Bingo, you have a retro'd machine in a couple of day. It never works out that way.:nono:


Its a shame you're in Canada. I would expect problems or for it to be fairly complicated, it seems that by looking at what you do its not though. What are some problems you usually run into with converting a machine that has servos, an ATC, VFD, and other common VMC features? Is there soemthing that needs tweaking or fine tuning that might take a few days? weeks? Is there any roadblock I might come to that will stop this from being financially viable (other than if the machine is wrecked of course. I mean just in the conversion process/troubleshooting)


You have the basic idea as you stated above - you would also add another breakout board from the 5i20 for Misc functions, tool changer I/O, coolant on/off, VFD control, MPG handle wheel input, way lube pump, etc


Would I have one 5i20 in my computer or a second one to control this. How does the breakout board attach to the 5i20? Would I only need one additional breakout board to control all those functions? Which one of those mesa electronics cards would I need to control them?

I can cobble together a PC for $150 or so as I have most parts already. The Mesa electronics cards come to less than $500. Am I to understand that a conversion can be done on this Mori for less than $1000?



One thing to make sure of with purchasing used machinery, often overlooked, is obtain all the documentation, including all machine parameters etc.
Al.

By documentation you mean the users guide and nc programming manual? Anything more I need to ask for (do most shops keep maintenance records?)
If they don't have it can I most likely call Mori Seiki and ask for it?

jeep534
06-08-2008, 01:32 PM
almost all stepper systems are Open loop

all servo systems are closed loop

the difference is where the loop is closed when AL was referring to open loop he was talking about Mach3 style of control which have no direct feedback to the software other than fault information.

With a mach3 style of control in a servo system the loop is closed back to the servo drive.

Mach3 treats these 2 sub systems the same (stepper and servo) it issues step and direction commands and the drives tell the motors to move a specific amount and what direction

Both stepper and servo systems when set up properly will shut down the software if the drives "fault out" by being over driven or over heated

The biggest difference between the two is speed and smoothness and cost. but the cost of servo's and drives have come down.

the cost of replacing the drives and servo motors on your class of machines with Brushless Ac servo motors and drives is about 1500 dollars an axis. ( auto motion direct) Glentek also has some stuff tailored to work with mach3 I am un sure about the price.

all of this talk of retrofitting assumes that the factory control is busted or otherwise worn out and replacement boards and parts are unavailable. the boss machine I am working on is old and the boards were burnt and it did not support features I felt were nessessary.

Mach3 supports
Network connections
thumb drive connection
4th axis
Camera
Probing
limited conversational prorgramming with wizards
ability to directly swallow a dfx file and run it (with esaycam)
supports touch screens
and can be programmed with Cam packages G-Code.

all that said it takes time to do a retrofit the learning curve is very steep and there is no manual out there that will tell you everything.

so

KyleH2
06-08-2008, 02:41 PM
It might be added that I can maybe get a copy of CamWorks for a reasonable price through my school's education alliance. CamWorks is awesome and I know how to use it so conversational programming isn't really an incentive to me.

So the servo motors in this machine I was told are most likely high voltage DC brushed as someone said above. Is there anything wrong with that type? Will they not allow me rapids of over 100IPM? $1500 x 3 is a lot if what I have can still talk to the software. What is the difference between brush and brushless? I understand the difference between AC and DC motors, but why choose one over the other?

EDIT:
Found some info on the types of motors:
http://en.wikipedia.org/wiki/Electric_motor#Brushed_DC_motors

Don C
06-08-2008, 03:00 PM
I live in port orange , Fl. and have a Enco Knee mill converted if you would like to see how it works. If so contact me of forum at dclifton2@cfl.rr.com
Thanks
Don
P.S.
I also have a CNC indexer on it.

jeep534
06-08-2008, 03:32 PM
It might be added that I can maybe get a copy of CamWorks for a reasonable price through my school's education alliance. CamWorks is awesome and I know how to use it so conversational programming isn't really an incentive to me.

So the servo motors in this machine I was told are most likely high voltage DC brushed as someone said above. Is there anything wrong with that type? Will they not allow me rapids of over 100IPM? $1500 x 3 is a lot if what I have can still talk to the software. What is the difference between brush and brushless? I understand the difference between AC and DC motors, but why choose one over the other?

EDIT:
Found some info on the types of motors:
http://en.wikipedia.org/wiki/Electric_motor#Brushed_DC_motors

IF...... you need to replace the motor drive setup.... not saying you need to or want to and if you are buying new. the servo motor of choice is a Brushless AC servo motor because there are no replaceable wear parts (brushes)
longer life with little or no maintenance.....

run what you have until forced....... to use something else.

archie =) =) =)

KyleH2
06-08-2008, 04:28 PM
IF...... you need to replace the motor drive setup.... not saying you need to or want to and if you are buying new. the servo motor of choice is a Brushless AC servo motor because there are no replaceable wear parts (brushes)
longer life with little or no maintenance.....

run what you have until forced....... to use something else.

archie =) =) =)

So as long as the DC brushed servos aren't worn out, keep them. Sorta the typical car mentality, if it breaks its a chance to upgrade it!

If I understand this correctly, the advantage of upgrading to AC servos if I have brushed DC servos is potentially longer life as well as rapid speeds, correct? Otherwise I can still use the brushed DC motors with whatever controller I go with.

jeep534
06-08-2008, 04:55 PM
So as long as the DC brushed servos aren't worn out, keep them. Sorta the typical car mentality, if it breaks its a chance to upgrade it!

If I understand this correctly, the advantage of upgrading to AC servos if I have brushed DC servos is potentially longer life as well as rapid speeds, correct? Otherwise I can still use the brushed DC motors with whatever controller I go with.

Correct.

archie =) =) =)

Al_The_Man
06-08-2008, 05:06 PM
By documentation you mean the users guide and nc programming manual? Anything more I need to ask for (do most shops keep maintenance records?)
If they don't have it can I most likely call Mori Seiki and ask for it?

Mainly the original OEM manual, schematics mechanical/electrical, and operator manual that lists the OEM configured M codes, hard copy of PLC Ladder if used.
Controller manufacturers manuals. Machine PARAMETERS.
I would not necessarily rely on the OEM, for an older machine.
If the DC servo's are in good condition, I would keep them.
There are 2 types of brushless servo, DC brushless and AC sinusoidal, with the latter considered slightly superior.
Both are equally reliable, i.e. no brushes, construction virtually the same.
If you want a demo of what the DCBL looks like electronically, see http://users.tinyworld.co.uk/flecc/4-pole-bldc-motor031102.swf
Al.

KyleH2
06-08-2008, 06:24 PM
Al, what are some examples of problems you run into when doing conversions on mills like this? Is there any problem that makes it not worth it financially to fix it? Assuming the motors, ball screws, etc. are ok and its just a bad controller, how much would a PC conversion using the 5I20 and linux based controller likely cost? Al when you do a conversion like this, how do you decide what controller to use, or is there just one you pick for everything?

Al_The_Man
06-08-2008, 09:29 PM
I would say the biggest reason that retrofit companies, per se, do not get involved with too many small machines like knee mills is the retro-fit cost over the replacement cost, this is why with smaller machines, the majority of RF is done by the owner.
Most of my retrofits are done on large machines where the RF cost will support a commercial system like Mitsubishi or Fagor for e.g.
The difference between a RF and a new machine is much larger, it make more sense to pay $50k to RF a machine with a replacement value of $1.5m.
When I have done PC based systems, I have used Galil motion cards, With some of their HMI s/w.
These are usually for specialized, unique applications and the operator input is dedicated to simple data, rather than G & M code programming.
Examples are 3 axis tube cut-off lathes and rolling machines etc. Also quite a few backgauges.
Some of these PC systems are coming up for around 20yrs now, and still running.
I have never used Mach or EMC.
You will occasionally see the odd Fanuc on a BP Knee mill, but it is a rare exception.
Al.

Jeremy A Flores
06-11-2008, 04:23 PM
For about $600 per month you could buy a new ProtoTrak DPM bedmill. No screwing around.

http://www.southwesternindustries.com/swi/prod_bedmills1.shtml

jeep534
06-13-2008, 10:01 AM
For about $600 per month you could buy a new ProtoTrak DPM bedmill. No screwing around.

http://www.southwesternindustries.com/swi/prod_bedmills1.shtml

If you are making a machine payment you want a tool changer.....

just my opinion
archie =) =) =)

buildyourown
06-19-2008, 08:04 PM
Thought I'd throw in my 2c as I went through the same thing about 6 years ago.
I ended up buying a used CNC mill on ebay for about what a good manual mill costs USED. The biggest problems I see with your plan is that the machine that you intend to build won't do the job you are contemplating. A HF mill with a NC retrofit will not mill a round hole. It will also not be ridgid enough to take cuts heavy enough to make production parts. Look for a bigger mill, with a 1 piece head and column, and box ways.
For $10000, you can get a lot of used machine.

chich2
06-26-2008, 10:26 AM
Kyle,
Great thread!!!! You have certanly hit some touchy subjects with this one. Great reading!!!!

ANYWAY, I started converting a cheap and nasty Chineese Knee mill back in 2006. I think the Hafco, Grizzly and all those are made in the same place with a different name tag for different distributers. I converted this machine to cnc because it was something I was interested in and always wanted to do. Not so much to churn out billions of parts from my home, but machining is my trade and I like machining. This mill has been a very fullfilling hobby and I am glad I did it. I fiddle with the mill conversion on and off and post pictures here on cnczone and also youtube video's as I go. You can see my Chineese HAFCO HM-52 mill conversion at http://www.cnczone.com/forums/showthread.php?t=25895
It is hidden in the Vertical Mill, Lathe Project Log part of the forum because when I first posted here the "Knee Vertical Mills" forum didn't exist yet.

Now comes my 2 cents and advice to you. You cant make butter out of dog $H1T! Yea sure you may get it to look and feel the same BUT one of them will make ya breath REAL BAD!!!!!! Now if you do things properly and adjust things right you WILL get a cheap chineese mill to do everything you need to do provided it is inside the boundry's of that machine. It's still a hunk of cast iron moving around like all the other hunks of cast iron out there. You WILL preform heavy cuts at the correct chip loads/feeds as any other mill of it's type and size. The major difference between the cheap machines and the identical but more expensive ones is.... The quality and reliability of the machine. Eg better materials, stronger motors, heavier castings with more webbing, machined parts fitting better. All that jass.
I may for example produce 100 perfect parts with my chineese mill before maintenance, as compared to producing 200 perfect parts with the same machine of a more reliable brand. For me at home, as a hobby, I say so what????
If on the other hand you were in this for full production you would be crazy not to go with a propper industrial machine. If time is on your side and your tollerances are reasonable, go cheap! However, If your livelyhood depends on it, invest in a real mahine. You guys in the US have got so many used cnc machines at your finger tips. Surely you can find a second hand machine working or not working to do what you need.

I am very sure that if I was producing something in full production, as bare bones cheaply as I could, I would be heavily searching for a dead industrial machining center and retro fitting it with modern after market electronics. So, it may go half the speed it originaly went, but half the speed of light speed (which some machines aparantly go) is still very fast. The price of the machine for it's quality in this senario would be a big winner.

Here is something to think about. Most people would not hesitate to go out and purchase a new car. But the same person would vomit at the thought of spending that sort of cash on a CNC machine. Funny hey?

To sum up. Generally if you purchase something new, you buy cheap, you get cheap. Yep my Chineese mill does everything "I" need to do. (That in no way means it will do what you need to do) If my mill breaks.....well.....I built it.....so you'd think I should be the first person to fix it. Just say I do a ball screw or fry a servo.......well like I said, I can fix 100% of it and know how and where to get motors, servo's, drives, VFD and all for a good price.
Take a good look at what you wish to achieve and have a real hard think about how you wish to achieve your goal.

Hope this has been helpfull and not attacked anyone.

Chich

DrDudley
07-02-2008, 02:58 PM
I would like to convert a wholesale tool 9 x 26 mill to CNC and would like input on this subject. I haven't purchased anything as of yet.

I sold my 12 x 36 lathe and am replacing it with a 13 x 40 lathe I think. I haven't really decided on that yet.

I would like to do some production work on both lathe and mill but need input. I have gone from being a pharmacist to being a machinist. Returned to college to get my electronics and computer engineering degree. I am going to also get a minor in mechanical engineering, depending on how the money holds out.

Please help.

KyleH2
07-02-2008, 08:16 PM
You already have a thread about exactly that. I sent you this thread because you were interested in a HF knee mill like I was. Perhaps you should link your original thread rather than making a completely unrelated question 4 pages into a thread that is not related.

etard
10-06-2012, 02:36 AM
What a weak way to end this discussion! What happened to the OP? Did he get a mill, or did he discover girls?

I doubt he will post here, perhaps I will search his posts...

I have a Clausing 8520 that is missing the spindle head, I was reading along to see if I should CNC this small mill or start from scratch. Anybody care to comment on my best course of action? This is merely for hobby work, but this thread makes me think it is not worth it...

Al_The_Man
10-06-2012, 12:37 PM
May be worth starting a new thread, this one is 4yrs old!
Al.