Adjusting $100 and $101, need assistance

Thanks to Inventables my machine is back up and running. Can’t say enough about their customer service.

Got it 99.9999% squared and true. (My estimate) So now I’m working on getting the steps per mm (steps/mm) set right.

On the Y axis, I told it to move 499 mm, it moved 500 mm. So I’m off by 1 mm at 499, or 0.2%
on the X axis, I told it to move 756 mm, it moved 761 mm, Off by 5 mm at 756, or 0.66%

With $100 and $101 both set to 40.000, using my rusty math, I should set $101 (y) to 39.920 and $100 (x) to 39.735.

Is my math right? Or am I way off?

Your math appears to be correct. I’d change the settings and re-test. That’s what I did on my machine, only I had to go the other direction to get it exactly right; i.e., my setting is 40.04.

Thanks Bill; Thats what I ended up doing. The math got me very close, but after a few adjustments and retries, I’m about as close as I can get. Ended up at 39.922 and 39.743.

My Z ended up at 318.700, spot on at 68 mm.

Now as soon as I get my wasteboard drilled and mounted I’m ready to start cutting again.

OK, I’ll bite, HOW did you measure your distances of X, Y movement to 3 decimal places? <-- I’d like to do this for my machine.
also - when you were finalizing your tuning, did you measure over different distances, or the 2 distances mentioned?
ooo- electronic calipers, maybe?

Russ from Coral Springs, Fl USA

I made my measurements in inches, which can be read easily to 1/64" (0.0156). One can even split a 64th, but I need my magnifying glasses for that. On my SO2, the gantry is Y; long axis is X. I have over 50" range on X, so I moved it all the way to the left, got a zero measurement on a good tape, then sent a command to move X +50". With that much movement, I got good accuracy I think. It was pretty close with the settings I had, but I tweaked it until I was exactly on 50" with a command of 50". My Y axis is just over 17", so I used 16" movements to check it and got the same setting as my X axis.

Excellent - thanks for the explanation.