On Monday, 4 June 2018 09:45:57 UTC+1, Bill wrote:
In message , Bill Wright
writes

Nothing worse than an under-powered power tool, be it a drill or a
planer or a lawn mower or a motor bike. Just leads to frustration and
forcing it, then an accident or a burn-out. Always use a tool that's
over-powered for the job.

I've seen plenty of things worse than an underpowered tool fwliw


I am the OP. Son has a decent Bosch battery drill, so that's good.

But..... I had it all wrong, I'm afraid.

I saw the job yesterday. The problem is not with drilling sheet ali,
it's with adding reinforcing struts to the ali frames he has already
made out of 1" square ali tube. The struts are also 1" square tube, one
being 5metres long, another 3metres.

There are 3 big triangular frames, and the struts are needed because
they don't seem rigid enough. The frame joints are some sort of plastic
inserts into the ends of the tubes. The struts will be bolted to the top
of the frame using studding, which I assume will also hold the mesh to
cover each big triangle.

So the problem is getting 10mm holes through two inch square ali tubes.

My smallest step drill goes up to 12mm, so we don't want to plough
through the lot in one go, but it has to be fairly precise.

I'm suggesting pilot holes, then the step drill from each sides of the
tube. He is worried that this will make the job long and tedious
working, as he has to, alone.

Drilling lots of 12mm holes isn't going to be quick, but the step drill has the huge advantage of a geometry usable on aluminium. If he opts instead for a standard drill bit & doesn't mod it it'll be a curse perfecting experience. Also a step drill will avoid a great number of bit changes.


NT