Machsupport Forum

Tangent Corner => Tangent Corner => Topic started by: Trebleplink on December 26, 2025, 12:38:30 PM

Title: Tormach 1100 mill head weight causing lost steps with Mach3
Post by: Trebleplink on December 26, 2025, 12:38:30 PM
I assembled my mill in 2008 with nema 34 steppers and Mach3 running on XP.  It's worked well except on Long jobs,  and after extensive troubleshooting, I found that the Gecko 202 6 amp drivers would overheat and my X-axis would be off as much as a half inch. Added forced air cooling on the heatsinks but still no fix.

A couple of weeks ago I really needed to do some long jobs.

I bought 3 new Nema 34 steppers and drivers from Steppers Online.  These have encoders on the shaft and create a closed-loop axis drive.

X and Y were done first with no problems.  A day ago I changed out the Z drive lifting the Tormach milling head that I've used for many years.  The problem is that in closed loop mode it will intermittently fault out when lifting the Z axis.  If I turn off the closed loop (normal stepper action) with a dip switch, all appears to work.

This tells me that the Nema 34 steppers don't have quite enough oomph to keep up.   There is no guidance offered on setting the 3 servo coefficients.  Pic attached.

SO, I'm making a counterweight with cable, pulleys and such, and don't know how much weight to use to offset the Tormach 1100 milling head.  I'm guessing 200 pounds, but I don't know and it's not published on the website.

Anybody know?