Z cutting to deep

What would suddenly cause my Z cut depths to be to deep? I don’t mean a few thou, but say .250 to .40. I checked the z calibration, it was fine. I’m stumped!

Insufficient Z-axis belt tension — should be ~20 lbs. Notes at https://www.shapeoko.com/wiki/index.php/Shapeoko_3#Belts

First thing I checked, Tension was fine, but I replaced the belt as a precaution. I disassembled everything and recalibrated the Z. Tomorrow I will run some new tests.

I design in vectric ( inch), and the post done in inch. I noticed the sender was set to metric (mm). Would that have the same effect? I will find out tomorrow.

20lb over what distance?

@Luke 20 lbs. for the run of the belt.

@edwan Conversion between Imperial and metric shouldn’t affect this. The other things to check:

If none of those pan out and you continue to have difficulties, check in w/ support@carbide3d.com letting them know what you have tried already.

I get the 20lb bits but lb of force on belts is measured over distance - i.e… 10lb across 1/2" deflection, unless you have e a frequency meeter.

The measure I was given didn’t include that information — makes sense! Unfortunately, 20 lbs. is all I’ve got.

I just lift the machine up using a luggage scale as I tighten it up and try to get 20 lbs. or so of force on it.

Very interesting. I put a belt drive on my motorcycle and can safely say without having a tension gauge and distance 20lb means nothing.

A better rule of thumb would be if the belt can be twisted 90 degrees but not much further is a better judgment. Still wildly inaccurate but…