I could be wrong on this, but I don't think you'll find that style of side thrust bearing new anymore.
Some hand wheels for crossfeed use that style as well, and Im thinking what guys have done is use a 3 piece needle bearing as replacement. where the two outer pieces are races that look like flat washers. The center piece being a series of caged needle bearings. The 3 together make a sandwich.
What you would need is inner and outer diameters, then search it up with a bearing company, mcmaster car, maybe grainger. Its not all that difficult just a little leg work.
For thickness, the needle bearing type will most likely be thinner, so you'll need to space it out with washers or a spacer you make.
Alternatively, you might make a brass thrust washer for the whole thickness. Cut some little oil channels on the sides and keep it lubed till you work out what you want. Tension on locking nut shouldn't be too great, you just don't want crossfeed screw moving back and forth, or pulling out of hole. So maybe just run the first nut up with your fingers, but lock 2nd nut tight to first. You want for crossfeed screw to spin nice.