Monday, September 12, 2022

Mostly for Other CNC Sherline Users With This Problem

 Suddenly the 0 value of X was changing.  Its notion of 0 was moving a fraction of an inch on each pass.  

1. I advanced X by 1" verifying that the marked lines on the table were moving an inch for each command.  No.

2. I turned off the controller and advanced the table 20 turns through the handwheel.  It moved one inch according to the markings on the table.  That told me the leadscrew was mechanically sound.

3. The setscrew that locks the stepper motor to the leadscrew was not perfectly tight.  I switched to the new higher-torque motor for X recently, and I suspect checking the tightenness of that setscrew periodically is in order.  Sadly, Sherline has those setscrews in a booger of a position to tighten: a tiny hole in the side of the motor mount.  It is of course on the far side from where I can see it, so remove the screws that hold the base to a big piece of wood to keep the mill from walking away.  (Not usually a problem on Bridgeport mills.)

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