Re: [VAC] New Kid On the Block

["Dr. Gerald N. Johnson, P.E." <geraldj@xxxxxxxx>]

Stripped threaded holes may be fixed by a machine shop with a helicoil
insert, or by welding shut and drilling and tapping new. The helicoil
requires drilling oversize and tapping with a special tap, then screwing
in a spring wire insert that fits the old bolt. There are also solid
threaded inserts that use standard taps. Welding and redrilling is the
most prone to disaster from drilling in the wrong place or the welding
destroying the cast drum. Helicoil is probably a bit more expensive for
tools than the alternative, but many consider it to be stronger.

The helicoil insert locks in place.

Gerald J.