[CNC] Wanting To Pick Up My First Cnc Mill

[Sendit]

Hey everyone, been thinking about picking one up for prototyping and making parts in general. Although other than the tormach, is there any turn key machine? I have been thinking about the G0704 machines but not honestly not sure about grizzly. I had a bad shopping experience and that's one of my concerns.

I thought about a tormach but with the money spent I could get a Fadal which is more power, bigger work envelope and will cost me the same amount. Also they aren't expensive to repair like a hass but do cost more than a tormach.

 

[TomS]

Quality Machine Tools offers a ready to run CNC mill. Check out their web site at http://www.machinetoolonline.com/.

I converted a PM-932 and am very happy with the quality. Haven't had a need for after purchase service/warranty but several others have posted that post sales service is outstanding.

Hope this helps.

Tom S.

 

[Sendit]

These are Taiwanese machines? Correct? How accurate are these compare to others say the Tormach?

 

[TomS]

These are Taiwanese machines? Correct? How accurate are these compare to others say the Tormach?

What accuracy tolerances are you looking to hold? When I first started running my machine I could hold less than .002". Now that I have run it for ten months it's loosened up a bit. Still can hold less than .004" easily. Snugging up the ball screw bearing preload and installing oversize balls in the ball nuts will get me back to where I started. Just need to take the time to get it done.

I believe the PM-45/932 are mainland China built to Quality Machine Tools specifications. I would give Matt a call at QMT. He will be more than happy to answer your machine specific questions. I have no experience with Tormach machines other than what I have read. I gather that those that own them like them a lot. The only negative comment I've heard is they are under powered but cannot verify that it is true.

Tom S

 

[cozmogeek]

I wouldn't be messing with this grizzly conversion if I could've afforded a tormach. It's a good learning experience vs just buying a cnc machine already done.

 

[TomS]

I wouldn't be messing with this grizzly conversion if I could've afforded a tormach. It's a good learning experience vs just buying a cnc machine already done.

I agree. Cost was the major decision maker for me. However, converting a mill was a fun and educational experience.

There are a couple of good conversion threads by jumps4 and jbolt in the "Machine Build Logs" section of the "CNC in the Home Shop" section of this forum. My conversion thread can be found here: http://www.hobby-machinist.com/threads/taking-the-cnc-plunge.24858/. This should give you a few ideas on how to approach your build. If you have any questions just ask. There are several people on this forum with a wealth of knowledge.

Tom S.

 

[JimDawson]

These are Taiwanese machines? Correct? How accurate are these compare to others say the Tormach?

Accuracy is a function of quality and fit of the base machine, the control system and the mass of the machine. It also depends how fast you want to remove material. Most lightweight (500 to 1500 lbs) machines can hold good tolerances, but not at high material removal rates. Even most stepper driven machines have a theoretical position accuracy of 0.0001 or 0.0005, and under very carefully controlled conditions they can hold that accuracy if they are mechanically sound. If the table has a good fit, and the machine has zero lash leadscrews the accuracy should be pretty good. Not all ball screws are zero lash. Some single nut system are hand fitted with the proper balls to achieve zero lash, but the most common zero lash system is double nut ball system where the nuts can be tightened against each other to preload the system.

Since you mention Fadal and Haas I assume you have the room for a larger machine. And since you are interested in prototyping as well as production, I would be looking for a used (or new) 10x50 CNC knee mill, that also has handwheels for manual use. I find that having the manual capability is handy for many operations. These will run about 3500 lbs, so a reasonably stable platform.

Here is one example of a machine that is close to you https://eastnc.craigslist.org/hvo/5443116247.html

Machines like this example started out as a good quality manual machine, were imported into the U.S.A. and retrofitted professionally by a shop and then sold under a number of different brand names. I still have not figured out what company was doing the retrofits. Maybe it was Anilam, as they all seem to have Anilam controls on them.

As stated above, Quality Machine Tool is a good resource also.
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[Sendit]

Accuracy is a function of quality and fit of the base machine, the control system and the mass of the machine. It also depends how fast you want to remove material. Most lightweight (500 to 1500 lbs) machines can hold good tolerances, but not at high material removal rates. Even most stepper driven machines have a theoretical position accuracy of 0.0001 or 0.0005, and under very carefully controlled conditions they can hold that accuracy if they are mechanically sound. If the table has a good fit, and the machine has zero lash leadscrews the accuracy should be pretty good. Not all ball screws are zero lash. Some single nut system are hand fitted with the proper balls to achieve zero lash, but the most common zero lash system is double nut ball system where the nuts can be tightened against each other to preload the system.

Since you mention Fadal and Haas I assume you have the room for a larger machine. And since you are interested in prototyping as well as production, I would be looking for a used (or new) 10x50 CNC knee mill, that also has handwheels for manual use. I find that having the manual capability is handy for many operations. These will run about 3500 lbs, so a reasonably stable platform.

Here is one example of a machine that is close to you https://eastnc.craigslist.org/hvo/5443116247.html

Machines like this example started out as a good quality manual machine, were imported into the U.S.A. and retrofitted professionally by a shop and then sold under a number of different brand names. I still have not figured out what company was doing the retrofits. Maybe it was Anilam, as they all seem to have Anilam controls on them.

As stated above, Quality Machine Tool is a good resource also.
.
.

Thank you all. I'm limited in the brands to stay with and to run from. Clasuing, Leblond, Sharp, Bridgeport, Nardini are the ones that I know are safe. My concern is replacement parts when needed.

 

[JimDawson]

I have not had a problem getting parts for my machine, but on the other hand I only needed a couple of pieces. The little lever that actuates the quill power feed up stop that I got from Bridgeport, and a quill return spring that I bought from an Ebay vendor. Bearings, ball screws, and other common wear items are standard off-the-shelf parts available from many vendors. I had my spindle rebuilt by a local vendor.

The biggest issue would be in the CNC controls, servo motors, and encoders. Those are the items most likely to fail. I would say that your comfort level on working on the controls might dictate your choices. On the other hand, even that hardware is pretty bullet proof. Fanuc and Centroid are pretty much the industry standards with an excellent support networks. Or you could do what I did and just build your own controls

 

[Sendit]

Making my own controls would require me to learn more than what I already have on the list to learn. Not saying that a bad thing, but do not want to get overwhelm. lol. I have no problem piecing together a kit, will be asking advice if ti came to that. I'm pretty mechanically and electronically incline. More so mechanical though. Electronics I know enough to be dangerous..haha