On Jan 15, 9:31 pm, "The Medway Handyman"
wrote:
After 2 years of venting tumble dryers, fitting waste pipes etc I finally
decided to buy a TCT Core Drill set from Toolstation. Cheap enough @£25 ish
so worth a punt and its seems pretty well engineered. www.toolstation.com
part number 41361.
[snip]
I have a 620w Wickes SDS with clutch, powerful enough? Failing that I have
a Wickes High Torque mains drill, around 85Nm torque - but no clutch, just a
large side handle. Don't fancy using that much :-)

If the 620W isn't enough for larger cores, how about the following
approach:
- Drill pilot hole
- Use large core as deep as it will go without jamming on both side
(this gives a nice clean edge to the hole)
- Use the largest core the drill can cope with to remove the centre
(might be worth getting an ~80mm core).
- Go back to the tried and tested ring-of-holes + SDS-chisel to finish
off.