This is a follow on from my previous question, Will standard M5 T-slot nuts fit these different 2020 aluminium extrusions?
The extrusion has this profile:
and here is a more in-focus photo, of four, in a 2 x 2 configuration:
The gap, between the bottom of the flange and the top of the circle, is about 4.4 mm high. The M5 hexagonal nuts are 3.85 mm thick, and 7.85 mm wide.
I have been using these 2020 extrusions with regular M5 hexagonal nuts (and M5 bolts, obviously).
However, I have recently found a need to use M3 bolts as well (to secure PCB mounted mechanical switches and endstop holders to the extrusion, for a 3D printer, see Complete list of fasteners for the Sintron Kossel).
The width of the slot is 5.4 mm and regular hexagonal M3 nuts are also around the same width (5.38 mm), and hence slip out of the slot. I guess that I could use a wider washer to hold the nut in place, but does anyone know of a "fat" M3 nut that is available, preferably one that is the same size as an M5 nut, but with a smaller M3 bore?
The problem has arisen because I should be using "European" 2020 aluminium, which takes T-nuts, and those come in a range of bores (M3-M6). However, I have been unable to obtain any, in Bangkok.