i think i'm gonna make some t-nuts. you can buy the standard ones but i want some in weird sizes. and producing a bunch is not that much more work than producing a couple, so i think i'll make some standard ones too.
if you don't know, a T-nut (or T-slot nut, technically) is a nut shaped such that it will fit in the T-slots that are found on machine tools. their shape allows them to slide along the slot, but bear against the slot when pulled upwards. this lets you use them to bolt stuff to the table anywhere along the length of the slot.
they're how my milling vise is attached to the milling machine table, and how the plastic fixture i made (the one i used to round the ends of the workmate handles) attaches to the rotary table. i want some to attach the rotary table directly to the mill table, some to attach more stuff to the rotary table, and a couple other kinds.
anyway, i won't get around to it this weekend, but i think i will order some steel (9SMn28K, if you were wondering — equivalent to ANSI 1215 steel, a free-machining steel). and maybe some cold blueing solution (which will provide some minor corrosion protection)