Teknic SD Servo motors

I have an older Plug and Play NEMA 34 CNC Control System on a 4x8 table. Has anyone tried the new Teknic SD servos that are suppose to be direct replacements for the Nema 34 Steppers?

Art Levitt

Hi Art,

I had the same setup that you have currently and switched to the Clearpath NEMA 34 motors and changed to the Centroid Acorn Control Board. The Clearpath motors have integrated drives, so the drives you have now will not work. You can still use the ESS, but you’ll have too some rewiring. Here is a link for wiring the Clearpath motors to the ESS. Homemade DIY CNC: Setting up ESS to Clearpath Teknic servos (part 4) - YouTube

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Just a FYI: You will not improve your accuracy or performance of your machine by adding the Teknic SD line. A lot of folks think they are going to get better resolution and that is actually the ball screws and the rack and pinion drive, not the electronics.

What Teknic DOES provide you is a stepper that will never stall. It also has the ability to be tuned to its particular use but your controller software won’t actually allow the stepper to take full advantage of that tuning.

So just be aware of that. Also, never exceed the numbers as defined by AvidCNC. Moving quicker because your motor doesn’t stall will tear up that pinion gear on the rack much. much quicker.


I agree. I can’t imagine needing more torque than the nema 34’s will provide. I bent an 8mm calibration rod to about 45 degrees once when I got fat fingered in the mdi window, the motors didn’t skip a beat. When pushing it that hard, the accuracy problems coming from the aluminum extrusions deflecting will be the biggest accuracy problem. One the other hand, some people just like to play with their machine and do something different (me too sometimes :slight_smile: ).

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Oh! The Teknic motors are really, really top of the line “steppers” in every aspect. By all means, if you have the $350, spend it. But the $50 NEMA 34 is just fine too.

Now, where the Teknic motors really shine is with the Meridian controllers and the SC motor line. SC Stands for “Software Controlled” meaning you use an API to talk to the motor. The result is “more than” a closed loop controller. You get back all of the torque and power along with position in the controller.

So, not promising anything, but I have two projects. I have a RP2040 based replacement for that Ethernet SmoothStepper. It is a one-to-one replacement which allows you to use LinuxCNC instead of Mach4 for a whopping $15 ( :rofl: ) . The second is a much longer term project that uses the Meridian Controller, ClearCore and the SC motors for a complete replacement of the entire control box.

But don’t hold your breath :stuck_out_tongue: All of that is a long way off at best.

PS. for those who know the Teknic motors are cool but don’t know why, its a thing called “G-Stop” and in a jiggly 8020 based CNC it “might” fix the harmonics that leave all those weird ridges all over your cuts; Teknic Meridian G-Stop Control: Ultra Smooth Motion Profiles - YouTube

That was an interesting video. I would love to see somebody get that up and running on an AVID. Right now I get rid of most of my ringing with pretty low accelleration values, which is fine for me since I’m retired (so quality is more important that run time) and I generally don’t run very fast feed rates anyway so you don’t notice the slow accelleration much. But it would be cool to see how well the G-stop works on something like a small font Vcarve or laser run.

I like to joke that my PRO60120 has a “spring in it’s step.” These 8020 machines ring when moving, and that is just a fact of life.

I was taught early that the parameters in the machine configs are the LIMITS, not the value your should be running the machine at.

If you are experiencing unacceptable ringing in your program then that is either one of two things; you are running the speeds too high OR you have large differences between the lowest speed and the highest speeds in the program.

So, either way, that is a programming problem and not something you can fix in the controller software configuration. Especially the limits configuration for the machine.

Myself, I would return the acceleration to the factory setting and never hit those limits again :wink: I have learned to be patient if I need fine detail.

You are essentially rewriting the g-code in the controller to account for all of that fancy motion profile stuff its doing. Its a lot of work and would be very expensive.

We shall see though! Its a time + pressure thing…