Viton O ring, 30mm inner diameter, 2mm cross section

Viton O ring, 30mm inner diameter, 2mm cross section

Details

Manufacturing Instructions

Step

The O-rings function as springs, to provide a return force on the nut that is pulled upwards by the screw. I use Viton O-rings, 30mm ID, as they provide about the right force. You can substitute for number 32 elastic bands, which are about 3mm wide and about 150mm in circumference (i.e. 75mm long when measured as a loop). If you use these, you should fold them in half, so you have a band that’s effectively 75mm in circumference. Buying a band that size is a bit difficult, but if you can get one, great!