From w5jv at hotmail.com  Sat Mar 28 11:59:09 2026
From: w5jv at hotmail.com (Doug Hensley)
Date: Sat, 28 Mar 2026 15:59:09 +0000
Subject: [Test-Equipment] How to bush a knob for a 1/8" shaft
Message-ID: <CH3P220MB20013295191060B636648BFC9154A@CH3P220MB2001.NAMP220.PROD.OUTLOOK.COM>

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






Visit https://www.qrz.com/db/W5JV for some great vacuum tube finds.



From radiotest at plymouthcolony.net  Sat Mar 28 13:35:36 2026
From: radiotest at plymouthcolony.net (Dale H. Cook)
Date: Sat, 28 Mar 2026 13:35:36 -0400
Subject: [Test-Equipment] How to bush a knob for a 1/8" shaft
In-Reply-To: <CH3P220MB20013295191060B636648BFC9154A@CH3P220MB2001.NAMP220.PROD.OUTLOOK.COM>
References: <CH3P220MB20013295191060B636648BFC9154A@CH3P220MB2001.NAMP220.PROD.OUTLOOK.COM>
Message-ID: <75f25e9f-d108-435d-b4ec-fa7921af7bd5@plymouthcolony.net>

On 28 Mar 2026 11:59 am, Doug Hensley wrote:

> 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 -

I have access to a very large, and quite old, hardware store, and I 
would begin there. I have, in the past, been able to find sleeves for 
similar purposes. I have drilled and tapped holes in the sleeves, and 
used very short set screws to attach them to the inner shaft.

If I cannot find something in hardware locally my go-to online is 
McMaster-Carr.
-- 
Dale H. Cook, GR/HP/Tek Collector, Roanoke/Lynchburg, VA
https://plymouthcolony.net/starcity/radios/


From n4buq at knology.net  Sat Mar 28 13:38:23 2026
From: n4buq at knology.net (Barry)
Date: Sat, 28 Mar 2026 13:38:23 -0400 (EDT)
Subject: [Test-Equipment] How to bush a knob for a 1/8" shaft
In-Reply-To: <CH3P220MB20013295191060B636648BFC9154A@CH3P220MB2001.NAMP220.PROD.OUTLOOK.COM>
References: <CH3P220MB20013295191060B636648BFC9154A@CH3P220MB2001.NAMP220.PROD.OUTLOOK.COM>
Message-ID: <536128651.9593988.1774719503990.JavaMail.zimbra@knology.net>

Doug,

I have some aluminum inserts from broken Tektronix knobs that have a 1/8" ID and a 0.280" (~ 9/32") OD.  If you could drill/bore the knob to fit that OD, it might work for you.  They're knurled so epoxy should hold them quite firmly.  I can drop one in the mail if you want it.

73,
Barry - N4BUQ

> 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
> 
> 
> 
> 
> 
> 
> Visit https://www.qrz.com/db/W5JV for some great vacuum tube finds.
> 
> 
> ______________________________________________________________
> Test-Equipment mailing list
> Home: http://mailman.qth.net/mailman/listinfo/test-equipment
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Test-Equipment at mailman.qth.net
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

From pmanfre at gmail.com  Sat Mar 28 13:39:03 2026
From: pmanfre at gmail.com (PeteM)
Date: Sat, 28 Mar 2026 13:39:03 -0400
Subject: [Test-Equipment] How to bush a knob for a 1/8" shaft
In-Reply-To: <75f25e9f-d108-435d-b4ec-fa7921af7bd5@plymouthcolony.net>
References: <CH3P220MB20013295191060B636648BFC9154A@CH3P220MB2001.NAMP220.PROD.OUTLOOK.COM>
	<75f25e9f-d108-435d-b4ec-fa7921af7bd5@plymouthcolony.net>
Message-ID: <CAE2hq2ADzE=0hJnGNSPGeYB+QZUKZ1bwp9=W9pb5QWBQwBHg0A@mail.gmail.com>

need pictures of what you have.   I have a draw of old knobs i can look
thru.

Pete wa2odo

On Sat, Mar 28, 2026, 1:35?PM Dale H. Cook via Test-Equipment <
test-equipment at mailman.qth.net> wrote:

> On 28 Mar 2026 11:59 am, Doug Hensley wrote:
>
> > 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 -
>
> I have access to a very large, and quite old, hardware store, and I
> would begin there. I have, in the past, been able to find sleeves for
> similar purposes. I have drilled and tapped holes in the sleeves, and
> used very short set screws to attach them to the inner shaft.
>
> If I cannot find something in hardware locally my go-to online is
> McMaster-Carr.
> --
> Dale H. Cook, GR/HP/Tek Collector, Roanoke/Lynchburg, VA
> https://plymouthcolony.net/starcity/radios/
>
> ______________________________________________________________
> Test-Equipment mailing list
> Home: http://mailman.qth.net/mailman/listinfo/test-equipment
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Test-Equipment at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

From radiotest at plymouthcolony.net  Sat Mar 28 13:53:40 2026
From: radiotest at plymouthcolony.net (Dale H. Cook)
Date: Sat, 28 Mar 2026 13:53:40 -0400
Subject: [Test-Equipment] WTB Millen GDO 46706 LF coil
Message-ID: <b9d617b4-4328-4945-aec1-4db53c209cca@plymouthcolony.net>

Doug Hensley's post about his Millen GDO prompted me to post here about 
mine.

I own a vintage Millen Type 90651 GDO. Some years ago I purchases the 
first four LF coils for it (46702, 46703, 46704, 46705). Millen sold 
them individually and as a set, and they are not difficult to find. They 
later introduced a fifth LF coil, the 46706, covering 165 - 225 kHz, and 
I have not yet found one. I have had a search running on the auction 
site for years with no hits. There were apparently fairly few of them 
made. If any of you have a Millen 46706 LF coil to part with I am 
interested in buying it.
-- 
Dale H. Cook, Semi-retired AM/FM/TV Chief Engineer, Roanoke/Lynchburg, VA
https://plymouthcolony.net/starcityeng/index.html


