127mm core drilling error, help please

MikeT · 2006-06-28T17:17:11+00:00

I have a few holes to drill and so does a friend so we bought a 127mm x150 diamond core drill between us, it came with a 200mm sds+ core drillarbor and a 10mm x 200mm tapered guide drill.I bought a Titan 1250watt sds+ drill with safety clutch from Screwfixand today attempted my first hole through single skin brick.I first fitted the pilot drill to the arbor and drilled that hole rightthrough, then fitted the 127mm core to the arbor and attempted to startdrilling.What a mess, it was just like trying to drill the core out without aguide drill fitted at all. The 10mm bit only sticks out 15mm in front ofthe core and after just a few seconds that had opened the pilot hole upso far that the likelyhood of ever getting the core to stay in onecircle is remote to say the least.What did I do wrong?My thoughts are that the pilot drill as a guide with just 15mmprotruding is just not enough to guide the core.I understand that once the core is into the brick by 20mm or so theguide is probably best removed, but how to get to that stage!Having tried it I would have thought a 13mm x 250mm or more guide drillwould be the ideal to keep everything going neatly until the core isdeep enough.Suggestions please.

Jun 28, 2006 23 Replies

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Ed Sirett 20 years ago

Instead of using the a guide drill it would have been better to use the blunt guide rod. The surface you wanted to start in must surely be quite weak (not brick like) to have opened out so much. I don't think the guide rod protrudes much more than 20-25mm from my core drills. Most of the kit was obtained from Screwfix although I've added some stuff to it later.

I suppose you may have been trying to drill from inside. I don't suppose you can get access to it from the other side? Perhaps that was why you were drilling 127mm?

If all else fails and you are really shafted then I guess you can fix a couple of battens on the wall in a V so as to support the drill until it starts.

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marvelus 20 years ago

Thats where the arbor goes.

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Brian Sharrock 20 years ago

Genuine question; when 'producing' a wide hole through a cavity wall ( plaster, brick, cavity, brick, rendering) should one drill a (narrow) pilot hole all the way through -then, and only then, widen the hole using the 'big' bit with its 'guide bit' fitted centrally.?

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John Rumm 20 years ago

If you want to be able to drill from both sides then that is the way to go. Alternatively you can just drill from one side, either using the pilot bit all the way through, or just to get you started after which you remove the pilot altogether and rely on the already cut section to guide you. (the inner leaf acting as a guide for the outer leaf etc)

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