A 5mm thick bed leveling knob
heres a link to the nuts i used which are a nice tight fit.
http://www.ebay.co.uk/itm/A2-Stainless-Steel-Nyloc-Nuts-To-Fit-Metric-Bolts-Insert-Nylock-Locking-Nylon-/291748760217?rd=1&ssPageName=STRK:MEAFB:IT
ROBS_NOB.stl | 64.9KB |