The AM Forum
March 28, 2024, 07:50:25 AM *
Welcome, Guest. Please login or register.

Login with username, password and session length
 
   Home   Help Calendar Links Staff List Gallery Login Register  
Pages: [1]   Go Down
  Print  
Author Topic: Seized Shafts  (Read 4692 times)
0 Members and 1 Guest are viewing this topic.
W1UJR
Guest
« on: July 09, 2005, 10:58:23 PM »

Early this morning, before I had to attend to "responsibilities", i.e. the YL, I was able to slip away to the Union, Maine hamfester.
 
Nice gathering and I returned home - what a surprise - with more radio stuff.
 
One of the finds was a very nice Johnson Kilowatt Matchbox antenna tuner.
Considering it is over 50 years old, it was in very fine business condition, with one problem.
 
Now, if you work on older gear chances are you are going to encounter the same problem which I found with my new Matchbox.
Seized shafts.
Yes, its not just a male problem, it happens to radio gear as well.
The bandswitch on the Matchbox was seized solid from time and disuse.
I tried turning it, but it was stiff and I was concerned that I would crack the knob.
 
So, after removing the nearly 50 some screws which hold the box together - really, count them - I was able to inspect the problem.
There, buried deep inside the tuner was a nice heavy duty ceramic two section switch connected to taps on the inductor.
The switch functions as a bandswitch, changing the inductor tap with each band selected.
 
My first thought was oil, so I liberally baptized the switch with penetrating oil - no success.
Next I got out the universal problem solver i.e. the hammer and tried gently tapping on the shaft, still no luck.
So I removed the inductor and the switch from the cabinet, even more screws, and after 45 minutes of effort I had the switch on the workbench in front of me.
I tried oiling again, still no luck.
I considered disassembling the switch for a good cleaning, but could not rotate it to access the retaining screws.
Then it struck me, I could try to heat it.
I reached for the trusty heat gun and fired it up to moderate heat.
I carefully heated the front section of the switch and then the rear section, not super hot, but warm enough not to touch.
Like magic the once seized switch rotated with little effort, clicking in firmly at each detent.
I applied some more oil, wiped off the excess, and then reheated the switch.
It seems the heat allowed the oil to be drawn into the switch, worked like a charm.
 
So, if you are ever faced with a stuck volume control potentiometer, switch, or shaft, and oil does not work, try a little from a heat gun or hair dryer.
 
Hope this helps someone else out.
 
 
73 Bruce W1UJR
Logged
w3jn
Johnny Novice
Administrator
Member

Offline Offline

Posts: 4620



« Reply #1 on: July 10, 2005, 10:12:03 AM »

This needs to go in the "Restoration" or "Hints and Kinks" section.

Thanks for that, Bruce.  Sometimes switches won't turn because the contacts have been welded... *that's* no fun, believe me.  :evil:
Logged

FCC:  "The record is devoid of a demonstrated nexus between Morse code proficiency and on-the-air conduct."
Vinnie/N2TAI
Guest
« Reply #2 on: July 10, 2005, 09:25:16 PM »

Heat from a soldering iron can be used on metal shafts. I have also found that tuner cleaner will work on frozen shafts. I think it softens up the old dried out grease
Logged
W3SLK
Member

Offline Offline

Posts: 2651

Just another member member.


« Reply #3 on: July 10, 2005, 10:04:18 PM »

We have some stuff that you can pick up at the hardware store. Its called Kroil. Advertised as the 'Oil that Creeps'. We commonly refer to it as Weasel Piss since it migrates into everything. It is a solvent so it is good around moisture. It has a distinct smell to it so sometime we will call it Millwrights' Aftershave. It works well in a chemical factory so I would imagine it would work easily on frozen shafts.
Logged

Mike(y)/W3SLK
Invisible airwaves crackle with life, bright antenna bristle with the energy. Emotional feedback, on timeless wavelength, bearing a gift beyond lights, almost free.... Spirit of Radio/Rush
Roy K8VWX
Contributing
Member
*
Offline Offline

Posts: 121


Pr. 4 -1000s Mod Pr. 5868


« Reply #4 on: July 12, 2005, 10:55:12 AM »

One of the best penetrating oils I have used is the PB Blaster brand and along with a little heat it works wonders.
Logged
Vortex Joe - N3IBX
Member

Offline Offline

Posts: 1639


WWW
« Reply #5 on: July 13, 2005, 09:50:13 AM »

Quote from: Roy K8VWX
One of the best penetrating oils I have used is the PB Blaster brand and along with a little heat it works wonders.


Roy - You aren't kidding! I used to think all penetrating oils were the same. Not so with PB Blaster. The stuff is really superior to anything else I've used.
Logged

Joe Cro N3IBX

Anything that is Breadboarded,Black Crackle, or that squeals when you tune it gives me MAJOR WOOD!
Pages: [1]   Go Up
  Print  
 
Jump to:  

AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
 AMfone © 2001-2015
Powered by SMF 1.1.21 | SMF © 2015, Simple Machines
Page created in 0.07 seconds with 18 queries.