Hi All,
I'm fitting a 4" extractor fan through a solid block wall. Rather than faff around with drilling lots of parallel holes, then attempting to chisel out the middle (as I've done previously), I decided to lash out and buy a suitable core bit.
It's an SDS TCD core bit, with a smaller guide bit in the middle.
110mm outside diameter.Should I use hammer+rotate with this bit, or just let it "grind" on rotate only?
Planning to start on the inside, cut to the 75mm depth the bit allows, drill through the guide bit hole to find the spot outside, then drill back in from outside. If this doesn't join up, and I don't think it will, I'll chisel out the centre of the cut, and go again. Does that sound reasonable?
On the inside, the wall has been faced with 50mm insulated dry lining board, but not yet taped or skimmed. I'll have to cut through that first before reaching the inside face of the block. Any reason not to use the core bit at slow speed and no hammer to make that cut first?
Any other advice or tips much appreciated on using this bit much appreciated.
Regards,
bookieb.