george (dicegeorge) wrote:

I have some plywood boards to fix to metal frames.
My plan is to use self-tappers.

OK...

Drill holes the width of the centre of the screws.

There's an appropriate hole for each size of self-tapper. This is a
reasonable guide:

http://www.anzor.co.nz/?t=67

Then use an impact screwdriver?

boggle

Is this the best way to do it?

The last is great if you really mean to mash up the screw heads and
shear them off. Use a proper screwdriver or, since there seem to be lots
of screws to fix, a cordless drill with a torque setting.