Drilling out broken self tappers

[Dave Plowman (News)]

Will tungsten carbide drill 'self tapper' steel?

I have some tiny ones broken off flush and wonder if my PCB pillar drill which uses tungsten bits would drill them out - but suspect they would break first due to not having anything to centre on?

[Dave Liquorice]

Or break due to snagging or being pushed off true on the rough, broken, surface of the self tapper. Can you file the end of the ST and center pop it?

[tony sayer]

In article , Dave Plowman (News) scribeth thus

I've done it a few times but its difficult getting the drill to start on the remnants of the screw..

[Bruce]

Good job for a Dremel.

[Steve Walker]

Ask your local dentist for his worn drill bits?

SteveW

[spamlet]

I don't think self tappers are likely to be particularly hard, so the real problem is holding the drill in position. I would make sure you do grind or file them down as flat as possible, and then try holding a piece of narrow tubing over them while you drill through the middle. You might be able to keep the hole in the right place like that. At a pinch, you might even find that, in reverse, a drill might wind them out.

S