[Boatanchors] How to bush a knob for a 1/8" shaft

[JAMES HANLON]

Message: 2
Date: Sat, 28 Mar 2026 15:59:09 +0000
From: Doug Hensley <w5jv at hotmail.com>
To: boatanchors mailman.qth.net <boatanchors at mailman.qth.net>,
	"test-equipment at mailman.qth.net" <test-equipment at mailman.qth.net>
Subject: [Boatanchors] How to bush a knob for a 1/8" shaft
Message-ID:
	<CH3P220MB20013295191060B636648BFC9154A at CH3P220MB2001.NAMP220.PROD.OUTLOOK.COM>
	
Content-Type: text/plain; charset="iso-8859-1"

I purchased a Millen grid dip meter (Model 90651A) over the internet only to have it damaged in shipping.  One issue is the two front knobs were broken.  As my luck would have it, while the left knob fits a standard 1/4" shaft, the right meter adjust knob is a 1/8" shaft.  Guess what the odds are of finding a matching pair like that anywhere?

So, if I could find a way to bush a 1/4" knob bore down to 1/8" and use a longer set screw, that's my first idea.

Has anyone solved this problem before and have you any suggestions?


Doug W5JV


Doug,

Try this.  Find or make a quarter inch tube with an eighth inch hole through the center.  Drill a hole for the setscrew through the side.  Slip it over the eighth inch shaft and then slip the quarter inch knob over it.  Install a longer setscrew and tighten it.

Jim, W8KGI






*************************