Z axis cutting too deep

when i enlarged my mill i also switched the z driver motor from a nema 23 to a nema 17 (had a dual shaft 17 but not the nema23 and i wanted to add the hand crank)

now its cutting too deep, at odd intervals, do i need to change the steps in the firmware? im fairly certain that they were the same step steppers (say that 3 times fast lol)

Step rate should stay the same - assuming they are both 1.8° steppers.
Happening at odd intervals sounds like something loose.

After upgrading, how did you calibrate the depth of cut?
I.E. If you lower a bit to touching your milling surface, and tell the machine to raise 0.25", can you roll a quarter inch bit underneath it?

Did you increase the current to the Z Axis via the GRBL shield potentiometer?

Also, going from a NEMA23 to a NEMA17 is a step down in torque of the motor, so if the depths are not uniformly wrong (like, sometimes it’s double what it should be, sometimes it’s triple), then you might also be missing steps because your motor is no longer strong enough to raise the bit at the speeds you are commanding. If you have confirmed that your step rate is correct, I’d try lowering your Z axis rapid rate.

Check your current limit. NEMA 17s usually have a lower current rating than the 23s. The gShield has enough current capability to damage the NEMA 17s if the current limit is set too high.

well i feel dumb, i switched from mm to inch in easel, but i also milled the surface of my waste board flat and i am currently running a cut and will retest the cut depth after