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Speed controller for Vernon horizontal mill

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  • Speed controller for Vernon horizontal mill

    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:

    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:

    Click image for larger version

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    The circuit is likewise much simpler:

    Click image for larger version

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    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:

    Under the hood:

    Click image for larger version

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    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.

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    Thanks for readin' ... Bob

  • #2
    I like it.
    Super cool.
    Like old school radio chassis construction.



    • #3
      Neat Job AND thoughts
      Thanks for posting !

      Green Bay, WI


      • #4
        No belt/gear changes available? What happened to the original reeves drive?
        I cut it off twice; it's still too short
        Oregon, USA


        • #5


          • #6
            Damn. Now I'm gonna be way too embarrassed to show my quick and dirty but entirely functional front panel done with the label printer.
            "A machinist's (WHAP!) best friend (WHAP! WHAP!) is his hammer. (WHAP!)" - Fred Tanner, foreman, Lunenburg Foundry and Engineering machine shop, circa 1979


            • #7
              Originally posted by Tim Clarke View Post
              No belt/gear changes available? What happened to the original reeves drive?
              Gone. Well ... in a box in the back room, just in case. Its adjustability was replaced by the VFD and I repullyed it for more oomph at low speed cause the VFD gives me higher speed (180Hz max).