Centroid Community CNC Support Forum

Hello all,
Currently trying to figure out what spindle motor would be best for a CNC conversion on a mini lathe using acorn as my controller..

Thanks in advance
PJ

Identifying Lathe make and model with link to its manual and your expected RPM range would be a start to getting you an answer

It’s a micro Lux 7x14 true inch (C3). I’m building custom mounts and essentially just using the original lathe for the ways and headstock. This is why I just asked for generic recommendations because realistically everything is on the table as all brackets are full custom.

My main concern is using acorn cnc and making sure that the spindle motor is going to interface properly for closed loop. I’d like to be able to cut threads and what not. Right now I have a consew csm1000 sitting on a shelf but I was looking at DMM servos.. just not sure what is the best model of servo to get.

There are numerous threads here on spindle encoders. A search would benefit you greatly. None of Centroid's controls, including the Acorn, do closed-loop spindle control.

There are also a significant number of threads where others have tried using servos for spindle motors. You might want to take a look at those before you head down that path.

I’m not asking for spindle encoder help I’m asking for spindle motor recommendations, ie servos with encoders built in for closed loop control. Or other options. Btw I did search, not a lot here in regards to mini lathe spindle motor discussions

A few notes from the cheap seats......
Very few if any get the DMM products to work well with 0-10v control
You will need a quadrature encoder that meets centroids specs on the shaft, seldom will the motors encoder work

Question, do you plan on using both velocity (spin) and position (step and direction) modes?

I have not used my cnc lathe but am getting it ready. My answers may not be 100% accurate.

You will need an encoder if you want to do threading. The encoder does not interface with the spindle motor it syncs to the spindle itself. The encoder must be set up at a 1:1 ratio with the spindle. I think the acorn adjusts the feed rate and not the spindle speed when threading. I'm sure someone will correct me about that if I'm wrong.

You can likely use the motor that you have on the shelf. You will need some way to control it's speed but that is not likely to be a problem.

Yea I have all the manual speed control for the csm1000 but will need to figure out how to interface that with acorn.. that’s why I was thinking a all in one package like a closed loop servo that is known to work with acorn may be worth the money.. as of right now I have to figure out how to get the sewing machine servo to be controlled by acorn and figure out the encoder situation..

The easiest and best method, 3 phase motor with a good VFD
Add a spindle encoder belted at 1:1 with a timing belt to the spindle itself with a timing belt.

You are asking us to guess at what you have. Pictures, details about the current motor and current drive would help us better provide useful suggestions to you.

Some say they have a DMM AC servo working. I never got it to work. Not worth the trouble and effort. It would have to be belted at 1:1 to the spindle with a timing belt and at that, you would be at the mercy of the AC servo's top speed for your top spindle RPM.

Marty

Like Marty said the easiest is to use a 3ph motor and VFD. If you require a smaller package, then by all means use a servo motor and drive.

I've had good luck using Leadshine servos to drive lathes, even some setups that use a single servo for both 0-10v controlled speed and step and direction for position. They are available from .2 to 1.8kw