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Updating a D&M 5 lathe

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  • Updating a D&M 5 lathe

    Well, I finally did it. I found and bought a CNC lathe project off Ebay, shipping it from Florida to Alaska. The base is an old mini computer from the mid 80s with some nice electrical parts inside, complete with a 40 meg hard drive the size of a shoebox and an 8" floppy drive.

    Mechanically it seems fine or fixable, but the breakout board and the stepper drives are missing. The toroidal transformer works, supplying 45V DC across the capacitor and 26.1V AC to the motor board.

    I am not sure if the motor board works as I did not test it before I went back to work for a couple weeks. I have no reason to suspect it is bad.

    I'm wide open to advice, but I plan to run it with an old Windows XP computer running Mach 3 to a CNC4PC C11G breakout board with Gecko G201x stepper drives. This seems to be a common upgrade path judging by older relevant posts on CNC zone. I basically picked the 201X stepper drives out of a hat - I'm not sure what is best in this situation.

    I can't read the scrubbed labels on the old NEMA 23 stepper motors and I assume they are 25 year old 70 oz-in motors. I plan on upgrading them after I get this machine going.

    I've looked over old posts on cnczone, but I can't figure out if that power supply will run higher power stepper motors. How can you determine what a power supply is capable of delivering?

    What would be an optimal torque motor given this power supply and lathe bed/cross slide construction?

    Is this an optimal component combination (Mach 3, C11G BoB, G201X stepper drives). I know you get what you pay for, but is there a cheaper alternative?

  • #2
    Changing the steppers to newer ones is not really going to get you much. I wouldnt bother. I would spend the little extra money and get the 203Vs. I am pretty sure those motors are old vextas.

    Did you get the tailstock quill or is it missing? Looks like a pretty well built machine. I am pretty sure those motors are old vextas.


    • #3
      I'd go with G251 drives, they're more than enough for small motors and cost ~$40 less than the 201s. My mini-mill has them driving 3A 425 oz-in motors and they work great. IIRC the only difference between the G203V and G201 drives was that the 203s have a bunch of added protection features for increased idiot-proofing.


      • #4
        Thanks, guys, for the replies. I've been working fairly long hours lately and haven't spent much time online lately.

        It is a pretty stout looking machine. I imagine it could be turned into a pretty capable machine.

        Nope, not tailstock quill. It is just a bit under 1" diameter with a 1/4x20 female thread in it to move it axially. The tailstock will be the last thing I fix on this as I can't think of too many projects where I will be needing it.


        • #5
          I've made a lot of progress since January. I cleaned up the lathe and gutted all the old electronics (and useless labels) except for the power supply.

          It was a tough decision to keep the old 90V DC motor over going the AC route. I made the decision after I won a Vari-Pak DC controller with a lowball bid. It cost more to ship than to buy. After wiring it and testing it, there seemed to be enough torque at middle speeds to turn the spindle under any load this lathe should be cutting.

          The complete enclosed speed control would not fit in the cabinet, so I pulled the two cards inside the enclosure and put it in a good spot in the lathe:

          The Gecko 540 fit in what spot was left.

          Configuring Mach3 was tough until I discovered the configuration video at The program was up and running after watching the 15 minute video. I got Mach 3 to operate the steppers and stop at 3 of 4 limit switches. Gotta figure that one out - handheld magnet will trip the limit, but the installed magnet won't...

          The second test run taking a ~0.025" cut of aluminum. I made 3 AXA toolholders to use 3/8" toolbits at the right height:

          The control panel as of today: From left to right, the speed control, speed under local or Mach3 control, motor run/jog from the Vari-pak DC control box, 3 motor indication lights, and an E-stop on the bottom using a SPST switch. I want to add a real Red Mushroom E-stop, add an on/off switch, spindle speed indicator, and an ammeter for the spindle. Yeah, its ugly, but I'll fix this after I get the bugs worked out of the whole thing.

          I'll next work on figuring out the Mach3 tool tables and making ball handles for other machines week with G code.


          • #6
            The jobsite with all its warts and blemishes:


            • #7
              Great thread, this really helped me overhaul a D&M 5 lathe I acquired. I actually used the same Varipak controller and the G540. I purchased new steppers, made some new belts and I can now control the X and Z movement. I hooked up the VFD to mach3 and I can use mach3 to turn the spindle on and off but I am having some issues getting to vary the speed.

              Would you have the VWM and pulley settings you used in mach3 ?


              • #8
                Originally posted by Draax View Post
                ....made some new belts and I can now control the X and Z movement.
                Man, it must be tough in AK, made your own belts?

                Must've missed this thread; thanks for resurrecting it. I thought I'd seen all the small CNC lathe retrofits. This is a great looking machine! Wonder if the OP has it doing meaningful work?

                "Accuracy is the sum total of your compensating mistakes."

                "The thing I hate about an argument is that it always interrupts a discussion." G. K. Chesterton