Seemed like a bit of blasphemy, adding crappy 3D printed parts to one the icons of “make it as good as is possible” machine tools, however I think it is sound engineering; its out of sight, works and saved a ton of time.
The task was to enable all of the machine’s original controls with an installed VFD.
The device holds a pot that is attached to a shaft via a set screw. At the other end is sprocket that is driven by the lathe’s original chain mechanism.
In the middle of the main bracket is a “brake”. The brake is mounted rigidly to the bracket, has a bass insert and is split to allow tension adjustment. Its function is to provide low friction so the speed control knob stays put where you set it.
Photos of 3D printed potentiometer speed control.
An improvement would be stops so as to not exceed the the pots range of motion; in the interim I think I’ll just be careful.
