36inch Hole

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Big Kev
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36inch Hole

Post by Big Kev » 23 Sep 2017, 09:09

Hopefully I've posted this in the right place. My brother-in-law has some very ornate table legs he wants to make lamps out of. He needs to drill a hole, from top to bottom (3ft) and is after suggestions on the best way to do this. He's limited to a hand held power drill.
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Stanley
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Re: 36inch Hole

Post by Stanley » 23 Sep 2017, 09:53

It's not going to be easy! He needs to find someone with a lathe that has a long bed (before you ask, longer than mine!) and a drill at least 2ft long so the legs can be drilled from each end as the hole will almost certainly wander because of the grain. You can buy drills that length or make one by welding an ordinary drill on a piece of rod. Best of luck with it!
A general principle to bear in mind is that the best chance of getting a true hole is to rotate the leg against the drill and not the other way round.....
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Re: 36inch Hole

Post by PanBiker » 23 Sep 2017, 09:58

The problem will be keeping the bore central, what's the diameter of the legs?

I know long masonry drills end extensions are easy to come by as I have a few myself. Not sure if you can get the same in a wood drill or auger. In a lathe setup you would rotate the work piece around a centre and use a fixed bit but you would need a big lathe.

I suppose you would be able to go in from either end and halve the problem but I think you will need some kind of jig for controlling the alignment of the drill bit. How about clamping the drill to a surface and arranging a jig to guide the leg accurately onto the bit, you would need an 18" or greater length bit though.

Stanley was posting while I was typing this and of course it would be better to rotate the work as in a lathe.
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Re: 36inch Hole

Post by Big Kev » 23 Sep 2017, 10:28

Thanks for your input chaps, I'll see if we can build a jig. He has a reasonable sized bench we can clamp it onto.
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Re: 36inch Hole

Post by PanBiker » 23 Sep 2017, 11:33

If you were going to clamp the drill, a full box section in front to feed the leg into might be the best bet. That would stop any vertical and horizontal drift of the work piece. Only problem then will be arresting any tendency for the long drill bit to wander.

I take it the legs are not that big a diameter so the hole, if for cable only about 3/8"?

Just had a thought how about a square hardwood block with a hole through the middle same size as the drill to fit inside the box section and slide in front of the leg to keep the bit centred as you push the leg through?
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Re: 36inch Hole

Post by Stanley » 24 Sep 2017, 02:21

If you get a long masonry drill and give it a bit more back rake with a green grit wheel it'll drill wood OK. Perhaps even better than a normal wood bit or twist drill.
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