For those of you just tuning in at home, my Nichols horizontal mill has two ways to move the table X-axis; the fast-action rack-and-pinion lever, and, because this one's the "toolroom" model, conventional handwheels and leadscrews.
The Nichols has an odd table nut; in order to be able to be easily removed, it's just a half a nut, fitted into a recess in the saddle, with the upper half of the leadscrew supported in a closely-fitted channel milled into the underside of the table.
Factory replacements are of course nonexistent, and originals are rare, often broken or worn, and in demand by those wanting to retrofit the lever feeds over to handwheels. Point in fact, I've never even seen a picture of a factory nut.
Now, I wanted my new piece to be as strong as possible, as accurate as possible, and to last for years and years. So instead of the factory cast-iron piece, I went with a weldment fitted with brazed-in silicon bronze for the wear surfaces.
I have thirty-six photos documenting the process, but in light of the board's four-per-post limit, I'll boil that down a bit: