linkuk wrote:

"Ian Stirling" wrote in message
...
linkuk wrote:

"linkuk" wrote in message
...
Any advice for what sort of drills to use for drilling old very tough
concrete. No holes will be less that 6 mm diameter.

I bought some from B&Q that were supposed to be for concrete but they
were
a miserable failurs so were probably cheap and nasty ones.

I meant no hole will be GREATER than 10mm.

What sort of power drill are you using?
Do you need one hole, or ten thousand?

Sorry forgot the first question:
Its a bosch mains drills with hammer action.

For occasional holes.

Simply taking any masonry bit, and leaning on it with the drill on
hammer action, with the chuck fastened, with more or less any drill,
going round the right way will work.

SDS is not needed - but will make the holes take well under a minute to
drill, instead of well over a minute to drill.

If the holes are vertical downwards, occasionally blowing out the holes
can help.
if they are horizontal, removing the drill from the hole several times
during drilling helps.

You need to lean on the drill enough so that the hammer action engages.