Tools for drilling a bloody big hole

[Martin Pentreath]

Hi,

I need to drill half a dozen six-inch holes through the paving stones and underlying base in my garden. The idea is to get down to the soil so that I can plant some climbers up against a wall.

I could just hire the stuff. However, I could do with a new SDS drill, and the core drill might come in useful again one day. So how about this collection of bits and pieces? In particular would the drill be powerful enough to cut the hole?

SDS drill

(I'm aware I'd have to turn the hammer off for the diamond core drill.)

152mm core drill arbor etc in I'd be looking at around =A385 including postage, and I'd have the stuff to have and hold for evermore. But would it work?

Cheers!

Martin

[Stuart Noble]

The underlying base might be a problem. Random lumps of hardcore bouncing around and all that. Why 6" holes? IME climbers do best coming through small holes so that the roots are kept moist under the slabs. I've had self-sown passion flowers cover the whole side of the house coming out of a crack in the paving.

The idea is to get down to the soil

[Martin Pentreath]

Point taken, although I want to plant already-established plants in pots from the garden centre rather then sow them from first principles, so I need a hole big enough to get the roots through.

[:Jerry:]

How about - measure the thickness of paving slab, put a depth marker on the coring bit slightly shy of the actual required depth and finish off by breaking though the last 3mm or so with a sharp hit from a hammer?

[:Jerry:]

That is, a sharp hit to the unwanted part of the paving slab, not the coring bit!...

[John Rumm]

I would be slightly wary of trying to do a 6" core with that. It is not a power thing so much as a torque limit. The clutch on most SDSs is designed to let go at a point that is too soon for a big core bit. I have cut 107mm cores with my SDS on several occasions, but it is right on the limit of the clutch. The slightest snag and it will slip on the clutch. So you have to take a very light cut.

Something like:

designed for the job.

You may get away with it if you are only cutting the slabs rather than trying to do an 8" deep hole in solid masonry. You could always use a chisel bit on the SDS to finish the job once you have a nice round hole in the visible bit.

[The Medway Handyman]

Lateral thought. Remove the entire slab, plant green thing, cover brown stuff (I believe its called soil) with fabric & gravel/decorative slate chippings etc.

Easy job, decorative feature.

Only problem is you don't get to buy a new power tool :-(

[The Medway Handyman]

I have the Wickes jobby

£30 less than the Sparky. A complete beast of a machine, I can't think of anything that would stop it.

[John Rumm]

I thought you had the Wickes High Torque rotary drill (about £100) rather than a dedicated core drill?

That would certainly turn the core ok, although I had a feeling that one did not have a safety clutch.

If there is no clutch that would make it a bit of a liability with a big core bit when it snags - although to an extent you can mitigate this a by not doing up the chuck too tightly.

The dedicated core drills don't have huge amounts of torque (high certainly, but probably less than the Wickes beasty), but their clutch is set to release at a torque high enough to keep the core turning through most things, but not so high that you get a twisted wrist of a side handle in the gob when the core snags. Their rotational speed is a bit higher as well.

[John Rumm]

Well, he could with all the money he saved by avoiding the need for a core drill on the flower pot job! ;-)

[The Medway Handyman]

I do.

It doesn't - just a side handle about 18" long :-)

Or hanging on to the side handle like grim death :-)

[Lurch]

On Tue, 17 Jul 2007 03:55:42 -0700, Martin Pentreath mused:

Doubtful. This isn't a job to be done on a budget, unless you do it all by hand.

I've used a diamond drill and stand\rig before for drilling tarmac\hardcore\concrete and it is a piece of cake. SOmething similar to .

[Weatherlawyer]

Nothing like a thick layer of concrete all over the garden to flood everyone else is there?