I removed the slider for disassembly, final deburring, priming and paint.
There was a small amount of binding, which seemed to be happening at the point of transition from the fwd to aft side tracks. I later discovered that anchoring the rear slider track caused a small amount of sideways slip between the upper strip and the flat bar underneath. That caused the the UHMW block to bind very slightly, so I widened the gap a little and everything works perfectly now.
I made a 1" plastic washer to fit between the steel and the ally handle on each side. I then turned a press-fit plug to fit inside each axel, which I will weld and tap next.
