Repair of Set Screw Attachment for Tek-made VAR Pots


Jim Adney
 

Quite a few years ago, I came across my first broken Tek-made VAR pot, the grey plastic ones. The plastic had broken near where the shaft enters, so that the set screw could no longer bind tightly to the shaft. As spares seemed like they might be hard to find, I came up with a more permanent solution, which you can see here:

https://groups.io/g/TekScopes/photo/262268/1 and also the following photo

These rings are tapped 4-40, the same as the OE set screws, but the ring encircles the cross-shaped portion of the pot allowing plenty of tightening of the set screw. The new, longer, set screw passes thru the original 4-40 hole, but does not use those threads, so this repair will fix a pot with stripped threads or fractured plastic there.

I made a supply of these for myself and have used a half dozen of them on various 3 series plugins. They take up almost no more room than the original pot, so I've yet to encounter a place where this wasn't a quick and neat fix. I have a small supply of these if anyone needs one, or feel free to copy the idea and make your own.


Wayne
 

Nice solution! Haven't run across a need for one yet, but if I do, the lathe is right there waiting! Thanks for the post and the nice pictures!


Paul Amaranth
 

Quite an elegant solution!

Paul

On Fri, Mar 26, 2021 at 02:20:11PM -0700, Jim Adney wrote:
Quite a few years ago, I came across my first broken Tek-made VAR pot, the grey plastic ones. The plastic had broken near where the shaft enters, so that the set screw could no longer bind tightly to the shaft. As spares seemed like they might be hard to find, I came up with a more permanent solution, which you can see here:

https://groups.io/g/TekScopes/photo/262268/1 and also the following photo

These rings are tapped 4-40, the same as the OE set screws, but the ring encircles the cross-shaped portion of the pot allowing plenty of tightening of the set screw. The new, longer, set screw passes thru the original 4-40 hole, but does not use those threads, so this repair will fix a pot with stripped threads or fractured plastic there.

I made a supply of these for myself and have used a half dozen of them on various 3 series plugins. They take up almost no more room than the original pot, so I've yet to encounter a place where this wasn't a quick and neat fix. I have a small supply of these if anyone needs one, or feel free to copy the idea and make your own.
--
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@AuroraGrp.Com | Unix/Linux - We don't do windows


Dave Wise
 

You ought to upload the article to TekWiki at w140.com .


Dave Wise

________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of Wayne via groups.io <WAYNECL=AOL.COM@groups.io>
Sent: Friday, March 26, 2021 2:43 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Repair of Set Screw Attachment for Tek-made VAR Pots

Nice solution! Haven't run across a need for one yet, but if I do, the lathe is right there waiting! Thanks for the post and the nice pictures!


widgethunter <tubesnthings@...>
 

Nice! Been looking for a fix for the 1A4.Wouldn't mind getting some.Bernd Schroder

-----Original Message-----
From: Jim Adney <jadney@vwtype3.org>
To: TekScopes@groups.io
Sent: Fri, Mar 26, 2021 2:20 pm
Subject: [TekScopes] Repair of Set Screw Attachment for Tek-made VAR Pots

Quite a few years ago, I came across my first broken Tek-made VAR pot, the grey plastic ones. The plastic had broken near where the shaft enters, so that the set screw could no longer bind tightly to the shaft. As spares seemed like they might be hard to find, I came up with a more permanent solution, which you can see here:

https://groups.io/g/TekScopes/photo/262268/1 and also the following photo

These rings are tapped 4-40, the same as the OE set screws, but the ring encircles the cross-shaped portion of the pot allowing plenty of tightening of the set screw. The new, longer, set screw passes thru the original 4-40 hole, but does not use those threads, so this repair will fix a pot with stripped threads or fractured plastic there.

I made a supply of these for myself and have used a half dozen of them on various 3 series plugins. They take up almost no more room than the original pot, so I've yet to encounter a place where this wasn't a quick and neat fix. I have a small supply of these if anyone needs one, or feel free to copy the idea and make your own.


Jim Adney
 

On Fri, Mar 26, 2021 at 09:39 PM, Dave Wise wrote:

You ought to upload the article to TekWiki at w140.com .
Okay, done. Took me awhile to figure out where and how to do this, but I think I (pretty much) managed.

https://w140.com/tekwiki/wiki/Potentiometers/Repairs