[ARC5] [Milsurplus] Stuck WWII Connectors.

[Scott Robinson]

Folks,

Here's kinda the opposite problem. 1930's and 1940s table radios 
sometimes have cabinets made of Catalin plastic, with swirly patterns. 
They are very cool looking and can command prices up to $15k when in 
excellent condition.

So here's the problem: the plastic shrinks over time. The metal chassis 
was a fairly snug fit when new. Someone brings such a radio to a 
restorer to get it working. The chassis is now a very tight fit in the 
cabinet, and the restorer must extract the chassis without cracking the 
cabinet of a $15K radio and reducing its value by many K$.  If you 
succeed in doing this, you  can then file the chassis width down so its 
fits easily before you put it back together.

Whew.

/scott

On 11/15/20 11:54 PM, Robert Downs via ARC5 wrote:
> As has been said or indicated throughout this thread, the black phenolic insert is not "stuck" in the same sense that for example a screw that has been in a nut for decades may be stuck.  The cast phenolic absorbs moisture over decades and swells so that the original light push fit has become an interference fit.  No amount of Kroil, graphite, or any other penetrant or lubricant will help.  It may in fact make matters worse.  Removing the retaining screw and baking in a 200 degree oven for one to three hours is AFAIK the simplest solution.  The only other method that might work would be a vacuum chamber.  But it would probably take months or years instead of hours.
> 
> The only other method that works (which I used to do all the time before Dave figured out the oven fix) is to make a proper receiver and removal tool and press the insert out of the sleeve with an arbor press.  Then mount each insert in a lathe and reduce the diameter by 0.002 to 0.004".  This method does work but takes time for each one and requires that you have a good lathe with near zero runout and good reflexes.  And in 30 or 40 years, you would probably have to do it again.
> 
> Robert Downs
> 
> -----Original Message-----
> From: milsurplus-bounces at mailman.qth.net [mailto:milsurplus-bounces at mailman.qth.net] On Behalf Of W2HX
> Sent: Sunday, November 15, 2020 17:43
> To: B. Smith; milsurplus at mailman.qth.net
> Subject: Re: [Milsurplus] [ARC5] Stuck WWII Connectors.
> 
> Graphited or non-graphited? Kano Penephite, Kano Aerokroil or SiliKroil?
> 
> Eugene
> 
> 
> 
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