On 2014-04-26, wrote:

It's not in the screw, based on that the screw/half nut isn't engaged
when I turn the hand wheel. The roughness is spread over a hand breadth
of travel. Rack maybe? If I'm lucky I suppose.

Just having the half-nuts disengaged doesn't guarantee it is not
the leadscrew. Bend it just enough and it will bow to drag on one half
of the open half-nuts, thread crest to thread crest. Certainly worth
checking out.

Just one of many possibilities, of course.

Good Luck,
DoN.

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