Thursday, December 6, 2018

Stuck Threads

I am busy trying to machine the diagonal mirror holder, a 1.18" diameter rod with a 45 degree cut and a 1/4"-20 through it to hold a screw that goes into the spider that holds to the inside of the tube. 

This is slower than I expected. at least partly because the chuck that attaches to the tilting table has locked itself to the 3/4"-16 adapter that the 10-32 screw uses to bind that adapter to the table. Adapter has a through hole.  A 10-32 screw goes through that hole into a 10-32 hole in the tilting table.  I cannot get the 10-32 screw to hold that part to the table. Threads are okay; just retapped the hole in the table. The 3/4"-16 part may be sliding on the table face. 

Next step is a lock washer to hold the screw tighter to the adapter of the adpter to the table.  It is a through hole in that adapter; so I see no obvious way to remove it. I tried heating in warm water, but chuck and adapter are both steel, so no net expansion. Perhaps dry ice on the adapter to get a more dramatic and sudden shrinkage. Extreme solution: left hand tap into that through hole, throw it away when it is out.

1 comment:

Zendo Deb said...

Several versions of break-free in a spray can at Lowe's/Home Depot/your favorite auto-parts store. Stuff works pretty well, if the steel isn't truly rusted or galled.

A torch for heat. A can of a air (for computer cleaning) for cold. Though you have to careful of the heat.

Then your extreme solution.