Z-axis gets stuck half way up

So I’ve been doing some cuts when today I noticed my X-carve won’t pull the DW660 up above about the halfway mark. The motors couldn’t make enough torque. I tried turning it by hand and there’s noticeably more tension about halfway up the Z-axis than the rest of it. If I turn it by hand below that point the motor can move it up and down freely. This isn’t a problem for the thin aluminum I’m cutting but obviously something is wrong. I just don’t know where I’d start to fix this precisely without having to perhaps unnecessarily take it all apart.

I would start with adjusting the eccentric nuts on the Z axis,

if that does not fix it, I would next spray some dry lubricant on the thread.

Next if you are not using a ACME rod then get the ACME rod, it will improve the Z axis movement by a huge factor.

You can also increase the current going to the motor, but that doesn’t fix the immediate problem… try mechanical adjustments first the if all fails then up the current

Did you run the threaded rod completely up and down through the delrin nut a few times when you assembled it? It starts out pretty tight, and if there’s any variation on the rod thickness then it could cause this problem.