X- axis binds every 3-4 inches, not sure why

Sorry, gang…I know there’s a bunch of these already, and I have read them, but I didn’t see anyone mention this specifically.

I’ve lost X axis tracking, gradually, over the past 4-5 carves. It’s moving left with every subsequent cut, about .1 inches per pass.

When I try to move the spindle left and right along the X axis with the machine off, it moves perfectly for 3-4 inches, then binds. Applying just a touch more pressure pushes it past the jam, and then she’s free again for 3-4 inches, then lather, rinse, repeat. It feels as if a wheel is jamming but they’re all free. I was hoping the slippage was the gear wheel on the stepper shaft coming loose (which I will also check) but in the meantime I found this binding problem.

Do I just take the X axis apart at this point and rebuild the mechanicals? I can’t visualize what’s causing it to bind repeatedly at the same interval, when it’s on a different section of belt at each of those jam points.

Lil help?

Thx
Rich