[Boatanchors] How to repair stripped panel threads

[Ron]

Helicoil would work great for full threaded holes.
For a panel I would install a pem nut.
---
Ron



WA5CAB at cs.com wrote:
> John's reply later in this thread is absolutely correct.  The helicoil 
> is the preferred method in industry and the military for repairing 
> stripped threads.  I've used them successfully down to #2-56 UNC.  The 
> helicoils themselves are cheap, and in each thread size come in 
> several lengths.  The dollars are in the special tap and the installer 
> and drive tang breaker.
>
> A helicoil is a length of almost (*) square bar coiled up such that 
> the ID is slightly greater than the original thread's minor diameter.  
> The special tap has the same pitch as the original thread but a pitch 
> diameter equal to the original plus the radial diagonal dimension of 
> the bar.  You drill out the original tapped hole with the correct 
> diameter bit, run the special tap through the hole, and screw the 
> helicoil into it.  The helicoil has a drive tang bent across the inner 
> end that must be broken off after insertion.  If the length of the 
> helicoil exceeds the panel thickness, it is best to cut the excess off 
> with something like a Dremel tool and abrasive disk.
>
> (*) The bar is actually a "Squashed" square, as standard V-form 
> threads are 60, not 90 degree.
>
> There are some other methods.  Usable in sheet metal is the nut-sert, 
> which is somewhat similar to a hollow pop-rivet.  The drawbacks are 
> that it takes a relatively large diameter hole and leaves what amounts 
> to a flat washer on the outside surface.  Two others come to mind but 
> are generally only usable in aluminum or brass castings and wood.
>
> In a message dated 12/12/2008 11:30:44 PM Central Standard Time, 
> texasroadrunner at comcast.net writes:
>> I'm sure this subject has come up before, but couldn't find any hits via
>> google groups.
>> Wondering what folks on this list have used to repair stripped threads?
>> I've experienced way too many over tightened fasteners which attach BA
>> panels to their chassis.  Currently I have a bunch of panel screws on a
>> Navigator- some are too loose due to over tightning.    One gent 
>> suggested
>> dipping and curing toothpicks in Devcon epoxy and then placing them 
>> into the
>> hole before screw insertion.  Short of welding (JB?) a nut on the 
>> back end
>> of the threads, looking for other ideas out there.
>
>
> Robert Downs - Houston
> wa5cab dot com (Web Store)
> MVPA 9480
>
> ------------------------------------------------------------------------
>
> _______________________________________________

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