Where to find very small fasteners?

[MrDillon]

Hello fellow trombone forum users. Today I had to disassemble the linkage on my bass and when I put it back together the screw that secures one of the miniballs was loose and rattling. It seems as though the threaded hole in the lever is damaged and doesn’t allow the screw to properly bind. Luckily the screw sticks out the other end of the lever so I figured I could buy a nut to hold it in from the other side. I went to Home Depot and unfortunately none of the nuts they had were small enough. Where can I find a fastener small enough for this application?
Thanks!

[BGuttman]

Fasteners of that size are usually sold in shops catering to Radio Control (RC) models.

If you don't mind buying in lots of 50 or so, consider www.mcmaster.com

[brassmedic]

The RC fasteners tend to be 2-56 thread, but minibal screws are often 1-64 thread.

[Bonearzt]

I doubt ANY local hardware store would have anything that small...
DuBro might, Aliexpress, McMaster, as Bruce mentioned, Amazon....
Model airplane suppliers would be a good bet