Which size core drill for a soil pipe?

[ben1979]

I'm sure there is an obvious answer, but I can't find it! What size bit do I need? & where can I get one cheap? Toolstation do a 110mm one for £13, but the next size up costs loads more! Why?

 

[Gasguru]

Get a 127mm - remember the pipe will be at an angle through the wall so give yourself a chance. Even holding a mini level along the extension tubes to get the right angle does not leave much margin for error.

Also bear in mind often the socket of the branch will actually be inside the wall allowing even less clearance.

I paid £150 for my Marcrist but it still looks like new after many many holes.

If you're cutting through engineering brick then stitch drill. Even the best cores with water attachment struggle then.

I hope yopu have a decent core drill with a clutch not some Chinese carp, an 850 Watts a bit small 1400 better.

 

[ben1979]

That's a great help, thanks!

 

[chr15]

I'm sure there is an obvious answer, but I can't find it! What size bit do I need? & where can I get one cheap? Toolstation do a 110mm one for £13, but the next size up costs loads more! Why?

You need a minimum 127mm maybe even a 150mm,no point buying cheap,if your drilling through anything a bit hard the cheap ones won't touch it,the best in my opinion are Nimbus,then marcrist,turbolite etc. but if you've only got one hole to drill then have you considered hiring one?- and remember,the larger the diameter you drill,the lower speed you want,let the drill cut at it's own speed,dont force it and if its a dry drill which I imagine it will be,then make sure you clear the drill of dust regulary or else you'll get a jam up.

 

[ben1979]

Just two holes to drill in to soft brick, so figured a cheap one would be a good option. Did have a look at hire, crazy prices!!!