Re: Stuck capacitor

Todd K7TFC

Two thoughts. Try a product specifically formulated for penetration. PB Blaster, etc. Apply copiously every hour or so and let sit overnight. The other things you tried weren't meant for penetration, or they do not include agents to help loosen the stuck. That includes WD40, which leads to my second thought: don't use it on electronics or other precision gear. It was not formulated primarily as a lubricant but as a water-displacement coating. It does, in fact, leave a film which, over time, oxidizes into a sticky "varnish" (sort of like old gasoline can do). 

Years ago, I worked for an aerospace firm that used, and made, close-tolerance bearings, both rotational and linear, ultra-precision optics, and other rocket-science kind of stuff. WD-40 was banned from the plant. It wasn't just prohibited just from certain uses or applications, it was banned from the entire place. Machinists couldn't have it, plant maintenance could have it, and even the janitor couldn't have the stuff. Why? If any one had a can, it would eventually end up on some tech's bench, only to cause problems later. We could use silicones, teflon-based lubricants, or other fine polymer-free machine oil, but only if it was on a list approved by the chief engineer.

Don't get me wrong, WD-40 is great stuff. I used it the other day to free-up a pipe wrench I left in the rain all winter. Worked great. 


K7TFC / Medford, Oregon, USA / CN82ni / UTC-8
QRP (CW & SSB) / EmComm / SOTA / Homebrew / Design

On Tue, May 14, 2013 at 7:18 AM, John R. Lonigro <jonigro@...> wrote:

I have a "perfectly" good dual gang 400 pf variable capacitor from an
old Heathkit signal generator. The only part of it that is NOT perfect
is the fact that it is extremely difficult to turn. I cannot grab the
shaft and turn it by hand. It will turn if the shaft is clamped in a
vise. I'm hoping to attach a stepper motor to it and would like it to
turn a lot easier. I've tried oil, WD-40, solvent, and white bicycle
lube on both end bearings, but that didn't seem to help at all. The
center bearing, if there is one, is covered and not accessible.

Any suggestions before I break down and get a new one?


John AA0VE

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