In an earlier contribution to this discussion,
Pecanfan wrote:

If using a core drill, why not drill from the inside out?

'cause a) I'm nervous about the last bits of brick etc. hitting our
downstair's neighbour's window, which is directly under the hole and
b) I need to core a slightly bigger hole on the outside to take the
lip of the access bend.


drill for a core much bigger than 4", my 780W Makita SDS only just
coped with that.

Think I've got the same drill as you - HR2450? Great piece of kit -
definitely my best buy last year :-). So far, this year's best buy
is a £4 angle grinder from ScrewFix - £4 'a tells ya!!! Anyway, not
planning on abusing my drill with this job - I think the local hire
shop do a proper core drill with bits for £20 or so.


In think in your case I would be tempted to core bore a hole big
enough for the pipe (say 120mm), and then open out the final couple
of inches a bit wider to accept the elbow using a SDS chisel, rather
than make the whole length of the hole bigger than you need just so
the coller of the elbow will fit one end.

Yeah - I'll either be doing that or, if possible, I'll use two
separate core drills - using the larger from outside to cut a 1-2"
rebate into the brickwork as mentioned.

Andy

You *really* don't want to be operating a core drill when 20' up a ladder!
You wouldn't be *allowed* to do it on H&S grounds if you were being employed
rather than d.i.y-ing. You really ought to be doing it from the inside -
even if that means having someone else on the ladder to catch any large bits
of brick when you break through.
--
Cheers,
Set Square
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