forehead arms im pretty sure are feed strips for automatic crimping machines. The hold contact pins for connectors. Here is a set i made with them
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There is only one style that looks like the one on the props. You will know it when you find it. They are becoming difficult to find so you'll just have to keep looking until it shows up if there are none around on the usual ebay or etsy
Haha im sorry, i meant the non-knurled incorrect part on the 2016 list. I know there were smooth cone knobs made... it looks like the tire valve on the MOM Vader saber, ive been trying to ID it for a bitIt could very well be a Michell part i just dont see the aduster in there. I dont have any Michell parts to compare but could it be an upside down cone knob? Or one of the tonearm plate mounting screws or a speed control knob? Also could be some unfinished Mitchell parts. Its knurled around the perimeter.