Am I being dim?

I first of all drill right through the cavity or one brick external wall using a long 6mm dia. masonry bit (at a slight downward angle to the outside to avoid damp tracking inwards).

Then I use standard masonry bits (up to 18mm dia) with reduced shanks (done using a lathe) to enlarge the hole by drilling in from either side.

 

My house walls are reinforced concrete.
So bought a decent SDS drill years ago, I wouldn't be without it.

I just hate so called hammer drills, they hit a hard spot and move sideways, and they usually rotate too fast burning off the end of the bit.

With a SDS, you get the hole just where you want it, not in the place of least resistance.

 

The the local tool hire place got back to me today and said that an sds drill with a 16mm drill bit would be just over £20 for the day which I didn't think was too bad

 

If your never likely to use it again, its worth it.

If you think you might need it to put up the odd shelf, might be worth buying one.