The Home Machinist!

Bill what sort of control and motors did you use?
Spindle control?
Spindle encoder for tapping?

Thanks for sharing your experiences
Marty

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"Jack of all Trades, Master of None"

The control is a FAGOR 8025 control with Spectral Dynamics amps.

I have no idea what the motors are - just dc servo something. Nothing special.

Encoders on the motors, no scales on the table, could not justify the $$.

Spindle drive is a Danfoss vector 5 HP unit which allows direct voltage control for spindle speed and dynamic braking resistors.

It has an encoder on it for speed control only (good to +/- 10 rpm or so).

Because it is belt drive, never considered rigid tapping. I have floating tapping head for those rare occasions when I use it for such (2 times in 12 years maybe?).

Bob, I sent you a PM
Jim

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Tool & Die Maker/Electrician, Retired 2007

So much to learn and so little time.

www.outbackmachineshop.com

If you've got a nice manual mill that is worth something, you'll probably be better off selling it as a nice manual mill that is worth something (or keeping it as a manual) and then buying a CNC machine for a retrofit.

Getting a mill that was built for CNC often means you get a bigger/heavier mill, with bigger ways, Turcite on the ways, ball screws already installed, motor mounts already installed, a controllable power lube system already installed, and if you luck out you'll have useable motors/transformers/relays already on the machine. Then you get to graft the new motion control cards/CPU/PLC stuff onto all of that.

Ive put Centroid controls on a Tree 325 and a Tree 425. The first came with a functioning Dynapath on it which I sold. I replaced the spindle drive with a CT Emerson SPI Unidrive unit. On the 425 I needed to source the big transformer, various relays, a full set of DC servo motors but kept the Yaskawa servo drive for the spindle. I did add an encoder to the spindle motor and an add-in card for it to the servo drive to get closed loop, which helped a great deal on the torque delivered throughout the range, especially at low speeds. Both of these machines are single-gear 6000K spindles.

I know of one 425 with a Delta Tau UMAC controller. A friend has done more of a "home brew" retrofit on his Tree 325.

I think that if you want a machine for making models than conversion of one of the small mill/drills may make sense. But you may find that the control conversion tends to run about the same no matter what it is stuck on, and if you are converting a manual mill you need to have another manual mill and lathe handy to make all the conversion parts like motor mount plates etc.

The Tree quills are much larger in diameter than those on a manual Bridgeport. And the 30 or 40 taper spindles are sturdier too. A cnc can often push a lot harder for a longer time than a manual mill will, so starting with something designed around those extra loads is handy.

Many industrial mills determine location strictly from the servo motor encoders and do so with great accuracy and repeatability as long as everything is in good condition. I think the ideal would be to have linear scales too for absolute positioning, but I suspect many retrofit systems won't be smart enough to deal with dual feedback streams. Adding linear scales may be a case of better being the enemy of good enough.

cheers,
Michael

Thanks to all of you who have posted here. Here is an update on my efforts.

Whitey--one of the posters on this forum and this threade--told me about a Gorton mill that was built for paper-tape NC. The paper tape didn't work out, so the mill sat in the corner of a shop for years--in Denver, I think. Eventually Whitey rescued it, had the motor rewound so that he could convert it to VFD and fixed it up (although it was hardly used) and made some modifications so that it can be either manual or (later) CNC. He sold it to a friend who has not had time to work on it. I have agreed to buy it from him. I will go after it the first week-end in July. Hauling it from Colorado to central Texas on a trailer may be an adventure, although I hope it will go smoothly.

The mill was built with ball screws. It has (I think) the original NC motors. Eventually I hope to convert it to CNC.

I am open to suggestions as to what motors to use. At this point the plan is to use Mach3. Again, suggestions welcome. Tell me about controllers. Give advice from the most elementary up. Please.

My young granddaughter is a good photographer, and I have invited her to accompany us to Colorado and take pictures of "the big move." If that works out, I will post them on the forum. I'm excited, so I may post more than you want to look at.

Again, your comments are welcome. As the old serials used to say, " ...To be continued... ."

Thanks!

--Bob

P.S. This should probably be posted in the Live Steam section, but Whitey is looking for an orphan project. If you know of a goodie, please send him a PM!

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--Bob

Gorton NC mill converted to manual to be converted to CNC.

Welcome to the club!
Do take pictures and do not dismiss the motors that are on it so quickly. Let us know what brand/model they are.
Be safe on the move!
Marty

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"Jack of all Trades, Master of None"

Thanks, Marty!

I had not intended to "dismiss" the motors that are on it now. As a newbie, I simply did not know whether the might or might not work.

Thanks for your consistent support and advice. Love this forum!

Bob

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--Bob

Gorton NC mill converted to manual to be converted to CNC.