Flathead Drillbit

[Woggle]

Hi there

I'm trying to take off of our external masonry wall a metal box.

The screws are fairly large and have been in the wall for +30 years. They are drilled in without raw plugs.

Using a Bosch hammer drill (rather than electric screwdriver) I have managed to get 2 of the 4 screws out. However, I'm struggling with the other 2 - a couple of the drillbits I have used have broken.

Ideally I need a flathead drillbit - but larger than the set I have given the size of the screw. Any idea where I can buy larger drillbits - or any other thoughts on how I might be able to get the screws out of the wall?

Thanks!

 

[thomp1983]

A picture of the screws will help

 

[^woody^]

Use a wide screwdriver. Hit the screw first with a hammer.

 

[Mike13]

Sometimes if the first attempt is a tightening it can break the rust bond. Use an old fashioned hammer impact driver, one that you set the mechanism to tighten or loosen, then belt the end of it with a hammer. The shock usually helps it start.

If that doesnt work, then use a small metal drill bit and drill though the head down to the shaft, so the countersink ring of steel pops off.

 

[opps]

Impact drivers are pretty good at loosening stubborn screws.

Impact Drivers & Wrenches | Power Tools | Screwfix

Buy Impact Drivers & Wrenches at Screwfix.com. Compact & lightweight design fits into tight areas. Ergonomic comfort-grip handles. Delivery 7 days a week.

www.screwfix.com

They use a "hammer and anvil" to create rotational "bangs".

As @Mike13 says you can get manual versions that you whack with a hammer. And again, as he says, you can always drill out the screwhead.