M8 Track for Auto-Rewind Spool Holder

I wanted to use easy to source M8 hardware for the weight on my auto-rewind spool holder.

This is designed with a long enough M8 section to sit 6x 608 bearings on, which comes to around 80g - i chose these because 3d printer people are likely to have them lying around.

A better option though is to use M8 nuts and washers to weigh it down. I've settled on using 2x m8 half nuts (one top, one bottom), and 20x 8x25x2mm penny washers. This gives me a total weight of 95g, and seems to work perfectly.

I ran an M8x1.25mm tap along the thread before using it, but this isnt actually necessary - the first nut you run along the threads should be enough to clean off any blemishes.