View Single Post
Old February 13, 2013, 12:22 PM   #2
Join Date: March 4, 2005
Location: Ohio
Posts: 13,648
I expect this is some kind of calibration knob for a female 40-tpi thread that surrounds an adjustment shaft for the set screw to hang onto. It might be used to adjust a seater stem or a powder measure or any of a number of things.

As a knob, the knurled ring probably works as a jam nut to fix the position of the larger ring or drum at some point of calibration. If there are 25 graduations on the drum, then, once jammed so it turns the whole thread, they represent 0.001" per graduation of depth change into whatever female thread the other end engages.
Gunsite Orange Hat Family Member
CMP Certified GSM Master Instructor
NRA Certified Rifle Instructor
NRA Benefactor Member
Unclenick is offline  
Page generated in 0.03177 seconds with 7 queries