Removing a broken self tapper

Angle grinder.

Carefully.

Squirt with PlusGas and leave for a day, or a spot of diesel if you have no PlusGas. Then I'd try the one of the JML Screw Removers that Homebase are (were?) selling for =A34.99/set. But being self tappers they might be too hard for the remover to cut into to get a grip.

You could at least have modified it for small and made it a Dremel?

Frank Erskine wibbled on Thursday 26 November 2009 10:46

I raise you "thermite"

:)

How small?

Axminster do 3mm tungsten burrs which I used when I broke a drill inside a stud I was trying to drill out.

AJH

Cobalt drill bit

NT

Proper self tappers will be too hard to drill out. Grinding is a possibility with a high speed (air) die grinder. If you can support nearby from behind with something like a heavy lump of metal eg club hammer head, you might be able to punch it through. One or more small holes drilled close by in the panel might aid the punching process.

Not nice or easy which ever way you choose.

Bob

Angle grinder, make them flat & flush, leave the wreckage in place.

Ideally move the new fastener location sideways to dodge the mess.

To do this, you will need two things. An extreamly hard drill and some means of stopping the twist drill from going off the centre of the self tapper and through the softer metal around it.

The twist drill could have to be a solid tungsten carbide one (or possibly a C 1150 or D 200, but I have hit a brick wall in finding a source of them. They are considerably harder than a cobalt drill.) and the only way you can prevent it taking the easy way through the softer body metal is to use a hardened bush that can be clamped onto the body metal, to guide it through the screw. Unless you are very adept at making the drill stay on course.

An alternative, but maybe expensive way, would be to find someone who can electrically erode it, by spark erosion.

Good luck. If it was a local job, I would get out my hard drills and do it for you.

Dave

I do have tungsten carbide drills I use for drilling PCBs. But not sure I'd risk them on this - even if I could rig things up to use the PCB drill press.

Thanks for the offer. ;-)

Why do you need to remove them at all? Are there no other fixing points?

The 'if there are four screws two will do' syndrome? ;-)

Suppose they could be repositioned - but not until I'm certain they can't be removed.

drill and use stud extractor maybe.

Personally I'd _angle grind_ (TM) flat and drill 'next door' Or use CARBODYFILLER (TM)

Do I get extra points?

You might be able to drill them and replace... failing that:

cheers

Jules

Have you ever tried drilling a self tapper?

Snag is they are the fixing for a rubber seal - clamped between the body and a steel section. It's already a rust trap so I'd rather not have any extra holes.

large ones yes. Small ones, no.

Going back to your comments about having tungsten carbide drills for PCB's, could you get a pilot hole in the screws and open it up with the right sized cobalt bit, freshly ground, of course?

My thinking is, that if you have one of those 12 V and tiny hand drills, it would be ideal to control where the twist drill can wander. Just angle the drill slightly, at 90 degrees to the direction of error, until the tip is pointing down the centre of the screw and bring it upright again.

That didn't look right. If the twist drill is wandering to the left, you angle it to the left, until the drill cuts back to the middle of the screw.

Dave

In message , "Dave Plowman (News)" writes

Can't you just chip away at the rust until it falls out of its own accord ?