My Vernon mill has a 3 ph motor and VFD. Machines have belts and gears to obtain various spindle speeds and the desired speed can be determined by that classic 4 x SFM/Diameter. SFM is the relevant parameter but machines are only set up for RPM, so that formula is used. My mill controller does the calculation & uses the approach I used for my lathe controller. Lathe controller: https://drive.google.com/file/d/1RVR...ew?usp=sharing
The mill controller is much simpler as there are no belt/gear changes available. So the controller simply has inputs for the SFM and the cutter size:

The circuit is likewise much simpler:

The algebra for the resistor values is boring, but the lathe write up explains how it's done.
As seen on the photo there are other inputs besides the Cutter size & SFM (FPM): there's a toggle for direction (CW or CCW) & a Jog button. The Jog button uses a fixed RPM of 30, regardless of the other settings. The big red button at the lower left is Run. It's push-on push-off.
I described the Feed section in this post: https://bbs.homeshopmachinist.net/fo...orizontal-mill
Under the hood:

The panel label was really frustrating. On the lathe controller I painted the panel, printed the label on acetate, and glued it to the panel. I have a new printer now and it wouldn't print on acetate. And the adhesive I have (3M 77) dissolves the paint. The forum has lots of content re panel labels, but even the ones considered to be "inexpensive" or "reasonable" cost were way too much. It's just a panel! $15 was my limit. I settled on waterslide - it comes on a backing, you print on it and use water to release it from its backing. BUT ... it's like Saran Wrap only much thinner and much more delicate. It works great for small coffee cup decals, but my 6" x 8" panel was way over the top - especially considering all the holes that had to be lined up. It took me 4 tries.

Thanks for readin' ... Bob
The mill controller is much simpler as there are no belt/gear changes available. So the controller simply has inputs for the SFM and the cutter size:
The circuit is likewise much simpler:
The algebra for the resistor values is boring, but the lathe write up explains how it's done.
As seen on the photo there are other inputs besides the Cutter size & SFM (FPM): there's a toggle for direction (CW or CCW) & a Jog button. The Jog button uses a fixed RPM of 30, regardless of the other settings. The big red button at the lower left is Run. It's push-on push-off.
I described the Feed section in this post: https://bbs.homeshopmachinist.net/fo...orizontal-mill
Under the hood:
The panel label was really frustrating. On the lathe controller I painted the panel, printed the label on acetate, and glued it to the panel. I have a new printer now and it wouldn't print on acetate. And the adhesive I have (3M 77) dissolves the paint. The forum has lots of content re panel labels, but even the ones considered to be "inexpensive" or "reasonable" cost were way too much. It's just a panel! $15 was my limit. I settled on waterslide - it comes on a backing, you print on it and use water to release it from its backing. BUT ... it's like Saran Wrap only much thinner and much more delicate. It works great for small coffee cup decals, but my 6" x 8" panel was way over the top - especially considering all the holes that had to be lined up. It took me 4 tries.
Thanks for readin' ... Bob
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