Hobbed Bolt Maker

Update: Slightly resized the tension bearing holder and added a part to hold the bearing in. As well as a part to hold the pivot bearing in. (I had a problem with them staying in when testing)
Update: 02-11-18 : Added the option for a 6001ZZ bearing for hobbed bolts that are 12mm.

Parts needed.
4 608zz Skate bearings
6 M3x20mm bolts
2 M8 or 5/16th nuts
1 M8 or 5/16th bolt at least 25mm long
Misc Washers.
1 Tap

Mount bolt to be hobbed in extruder and mark position with permanent ma