I use my elite primarily to cut topographic maps, and have developed an issues around stopping and starting the machine using “run from line #”.
Previously it’s worked no problem, but on my current piece, each time I restart the machine the bit loses a fraction of a mm in the Z axis, resulting in a visual lip in the wood where there shouldn’t be.
I have an Easy Z tool setter installed and working, and use 3 in 1 oil everywhere every 20 hours or so of cut time. It’s also the heavy duty Z slider.
Does anyone know any parts that could be degrading or bolts that should be checked for tightness? Anything that would lead to this happening?
I recently built my own Z axis assembly, and remember when I removed the Z20 there was unexpected movement. I just checked it, and I notice there is close to 1 mm of play that the ball screw has between the top and bottom bearings. I am not sure if yours is the same, and if it explains in part what your are seeing, since I would expect the mass of the spindle (if using one) to keep a constant downward force due to gravity. One way to mitigate any effect of this might be to loosen and retighten the spider coupling, making sure to push it down hard before tightening it again on the motor shaft.
The toolsetter’s repeatability would have to be very poor to explain this result, but you could measure this, as well as any Z axis backlash with a dial test indicator.