Posted by Sherman in Idaho [24.32.202.166] on Thursday, May 02, 2013 at 11:58:03 :
Or maybe it's 1/4-32. Anyone have such a thing? I'm trying to repair an old doorknob, the kind where there's a square, partly-threaded shaft that both knobs screw onto, and a set screw in each knob to hold it in place on the shaft. I only have one of the screws, and it's 32 TPI. The OD of the screw is a hair over 1/4", but I'm pretty sure it's not 5/16. I almost ran a 5/16-24 tap down the hole to clean it up, until I realized the thread looks too fine. According to the thread tables, 1/4-32 and 5/16-32 are both in the "EFF" (Extra Fine Thread) series, but nobody seems to make such screws any more. MSC wants ~$30 for die, and I can't cut such fine threads on my lathe. The temptation is to just tap it out to 5/16-24, put a hex-head setscrew in it, and call it good, but I have this weird aversion to permanently altering antique machinery. Any ideas on where a guy might get such a screw, or better yet, anyone have one in their can of screws that they'd part with? I will rummage around and see if I can cannibalize another door knob too.
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