I recently bought and received three lead screws from
precisiontechmachining on ebay. I got two 18in and one 24in long 3/8-16 lead screws. They each came with a delrin nut which seems to work nicely. Unfortunately, the 24in one seems to have been damaged in the mail. I am trying to see if they will replace it.
It fits nicely between my linear bearing rails!
The ends are turned 5/16in. The 6mm ID skateboard bearings I have fit snugly. I might have to invest in angular contact bearings though.
The damaged 24in screw. It is not bad however it could cause significant whipping.