Cincinnati 15x54 traytop half nut lever difficult to engage.

I recently removed the apron and made a new bushing for the carriage handwheel. I cleaned the years of chips, oil, and debris off of the apron. Upon reassembly everything functions normally, however, when engaging the half nut handle it has a significant "hitch" when you try to engage it. If you bump the lever past this, the half nut engages as normal. But when you return the lever to the disengaged position (which is smooth) and try to re-engage it, the heavy bump or heavy cam-over feeling returns. I have the manual and i cannot find anything in troubleshooting about this particular problem

Just to be sure... You do realize the half nut has to line up with the corresponding threads in the lead screw, this will often stall movement of the lever until alignment occurs. The thread dial should be in time with the lead screw, but is not always the case. Try engaging the half nut with the lathe off, engage the lead screw ( move the apron forward or back until engagement occurs) then dis engage and re ingage without moving the apron or lead screw, to see if the problem still occurs.

Then there is another possibility, and that is a worn ridge in the half nut from people not fully engaging it during threading. I worked on a lathe with that exact problem at a local factory when the machinist couldn't seem to make useable threads, as engagement occurred at different depths of the nut and therefore different "lead" due to the wear of the nut. A very obvious ridge could be felt at two points while engaging the half nut.

Just my $0.02

The resistance in the handle occurs before the half nut has even begun to close, and well before the threads are even near the lead screw. I did check the alignment with the lathe to see if the threads were "pushing" the lead screw left or right, and they appear to be aligned properly. Its almost like the dovetail slides that the half nut jaws slide in has something causing it.

If it worked correct before you took it apart to make a bushing for the hand wheel and only after cleaning and reinstall it started to jam then one would have to think that your half nut likage got out of adjustment or weadging in the dove tails.
We had an old Reed lathe that the half nut linkage that raised and lowered the half nuts became loose in one of its pivot point and basically did what you discribe, it felt like a bind to engage but would disengage easily. Another lathe a Bradford had worn half nuts that got to be a problem engaging.
We had to machine new half nuts as none were available, solved the problem.

JENIUS said:

I recently removed the apron and made a new bushing for the carriage handwheel. I cleaned the years of chips, oil, and debris off of the apron. Upon reassembly everything functions normally, however, when engaging the half nut handle it has a significant "hitch" when you try to engage it. If you bump the lever past this, the half nut engages as normal. But when you return the lever to the disengaged position (which is smooth) and try to re-engage it, the heavy bump or heavy cam-over feeling returns. I have the manual and i cannot find anything in troubleshooting about this particular problem

Click to expand...

*UPDATE*, in my fastidiousness in cleaning all the years of schmutz off of the halfnut dovetail slides and detent, i neglected to re-lubricate all of the sliding surfaces and, when i re-lubed everything,
like magic, buttery smooth engagement and dis-engagement.