Ok i've got a real head scratcher here. i built my machine about 6 years ago and it has mostly been a fun toy and learning experience. it has its quarks and so anytime it did something strange like have a random motor stall, i woudl just slow the speed down and try again.

Fast forward to this weekend - i went through and rebuilt the parts of the machine that i knew to be troublesome, including doing a lot of alignment work on they Y axis, which is much smoother and stiffer now. Given this improvement, i expected to have better performance out of my machine.

i was working on cutting out a sign and while cutting the numbers, the machine stalled in the Y axis. Now in the past i have run about 40 IPM cutting and had very good reliability and repeatability. i was trying 50 IPM when the stall happened. i lowered the speed down to 40 IPM and it ran fine as usual. With the improvements i made to my Y axis, i can easily run 150 IPM rapids with no stalling, and have intermittantly run as fast as 225 IPM so i did not expect any issues at 50 IPM.

High Level Details:
-stall occured in the middle of the axis but if i change my start point it will stall at the exact same place in the g code every time regardles of physical position on the y axis
-there is no binding, it is very smooth
-the stall always occurs during a g01 command to move x and y by a small amount (around 0.005" give or take)
-the stall occurs both while cutting material and running in the air, so i dont think its torque related
-I tried increasing the speed in 10 IPM increments up to 100 IPM and the stall still occurs every time
-it never occurs at 40 IPM
-Nema 23 305oz unipolar with HobbyCNC board. its a 2'x3' cutting area. Y axis is the 2' axis.
-my machine almost never loses steps. if it is going to have a problem, it has a full on stall.
-i have had this happen before in the past where it seems to stall at a cartin line of code, but i always chalked it up to binding.

Things i tried:
-changing Mach 3 step and direction pulse width up to the max of 5 us
-using Sherine 1/2 step mode
-changing kernal frequency (tried all settings)
(note: i don't have shielded wire running my motors, in case that makes a difference in things to try)

I need some help as i am not sure what other settings to try. I know my machine is capable of running much faster than 50 IPM so i am not sure why it keeps stalling at this one line of code