New user, pre-owned machine, z-axis way off

Hi–last year I purchased a well-upgraded and lightly-used machine from someone who was moving. He was extremely generous and gave me so many attachments and spare parts and materials. The upgrades include more powerful steppers.

However… upon my first test cuts (cutting through 5mm ply to make a box) the z depth was obviously way off. At first I thought it was user error, but I’ve done a few tests and found that for every inch of of depth manually jogged results in ~3.25" of actual drop. So, in my attempts to cut 5mm ply it went 16mm… I am now out of 1/16" bits and there were some friction pyrotechnics…

Also, interestingly, I was required to jog in 0.1" increments because 1" movement causes the stepper to bind, and shriek. another red flag.

My machine has the acme rod, and not the M8 threaded rod. I’ve confirmed this in setup repeatedly.

The steppers for x/y/z are all upgraded and all the same make/model. I am very interested in troubleshooting this, because everything else is working like a charm! Bear in mind I’m very much a novice. Thanks!

It sounds like you need to calibrate the Z axis.
Although it seems kinda strange that its that far off if it was being used.

Thank you, yes. I must be that my connection through easel brought in default settings, he’d likely put in his own… I just manually reset $102=188.947 to $102=50 and it’s working. I think. with a ruler against it, it moves an inch per inch jogged… I’ll try to figure out a truly accurate number ASAP.

What controller? Sounds like a microstep setting.