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snafu[_3_] snafu[_3_] is offline
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Default Thread locking - Stainless steel into PVC

On 12-May-15 11:23 AM, Steve W. wrote:
snafu wrote:
I have a 1/2" x 20 UNF bayonet style electrical connector threaded
into PVC.

The PVC is the standard gray material bought as a round bar off the
shelf.

Mechanical constraints prevent using a locking nut or radial set screw
for retention.

Does anyone have any suggestions as to what chemical means might be
useful to lock or bond the (probably stainless) metal connector to the
PVC to prevent unscrewing?

Thanks.


Take the connector out. Mill a slot up one side to half of the depth per
width (1/8" wide slot Mill 1/16" deep). Install the connector and use a
drill bit to "transfer" the slot to the PVC and finish the hole to size.
(1/16" in the connector 1/16" in the ABS). Now take a chunk of PVC
welding rod or ??? that is 1/8" and apply some PVC glue and insert it
into the hole. Once it cures the connector won't move.
Basically a linear locking spline. Same idea as used on key lock thread
inserts. However instead of using the steel pins those use you have PVC.
That way if you ever did need to remove it you could heat the connector
and turn it to shear the PVC spline.



That's a great idea but there is likely to be 1000 of these made (I
should have mentioned that earlier). I'll save the idea for next time
I've got a use for it.