On 17/03/2019 09:46, Mathew Newton wrote:
I need to affix some insulated plasterboard to the underside of an IG Extra Heavy Duty steel lintel:

https://iglintels.com/wp-content/upl...heavy_duty.jpg
http://www.newtonnet.co.uk/permanent/lintel.jpg

My plan was to glue and screw it in place, using Fischer UX plugs into the aerated concrete blocks above. I therefore need to drill a few 6mm holes through the lintel and was wondering how easy this will be?

The main reason I ask is that I've always found drilling metal hard work, but then all my metal drill bits are those which either came with drills or assorted bit sets. I'm sure in both cases they're the cheapest of the cheap.

Ought something like this suffice?

https://www.screwfix.com/p/bosch-str...6-x-93mm/239fv

Any other tips?

Your basic plan is fine, but get yourself a set of cobalt drills,
Toolstation does a cheap set, or Bosch do them individually or as a set.
A bit more expensive than TS but *very* good.

The advantage over "normal" high speed steel "metal" bits is that they
won't blunt when you go through the metal even if you hit normal brick
or blocks, rather than lightweight.

That type of lintel ought to be easy enough to drill. RSJs are sometimes
more difficult partly because of the section thickness, and you can also
hit non-metallic inclusions.

There's a bit more skill in drilling metal than wood or masonry, you
need to have the right combination of pressure and drill speed and it
all depends on the size of hole. But a 6 mm hole with a normal domestic
mains or cordless drill should be no problem. Slow speed and quite a lot
of pressure, you should be able to "feel" when it is cutting.