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Making a 120mm dia hole....

Posted: Tue Feb 11, 2020 9:49 pm
by thatsnotafestool
A friend of mine is the manager at one of the Roman forts up here. They've got a larch that's been felled, very straight and about 400mm dia. They want to cut it into 1m lengths and then make a hole 120mm down the middle and about 300mm + deep. He asked me how to do it and I've not got much of an idea. Huge lathe ? Some machinery a shipwright would have ?

Any ideas ?

Re: Making a 120mm dia hole....

Posted: Wed Feb 12, 2020 4:46 am
by Meccarroll
thatsnotafestool wrote:
Tue Feb 11, 2020 9:49 pm
They want to cut it into 1m lengths and then make a hole 120mm down the middle and about 300mm + deep.
Any ideas ?
Sounds intriguing and I doubt I'd know the answer Roger but I don't quite get the bit about 300mm + deep and 120mm down the middle :?:

Re: Making a 120mm dia hole....

Posted: Wed Feb 12, 2020 9:06 am
by woodsmith
You could get a core bit, they do them 127mm that I know of, and cut more of a tooth shape into each of the tips. If the wood is green I would think it would work as you are going into end grain so you need more of a chisel shaped tooth. You would have to drill so far then chop out the core then drill/chop to the required depth.

Re: Making a 120mm dia hole....

Posted: Wed Feb 12, 2020 12:58 pm
by MJ80
120mm forster bits are available. You could use one with an extension, I'd probably use my core drill to turn it.
The bits are about 80 euros for a cheapy over here.

Re: Making a 120mm dia hole....

Posted: Wed Feb 12, 2020 3:24 pm
by jfc
Do they want to dowel it back together again :lol: