Boring very large diameter holes

Mon, Apr 5, 2004, 2:33pm (EDT-3) snipped-for-privacy@palimountain.com (Nesdon) claims: As I mentioned in a previous post, I have too many big logs. I want to bore a hole approx 12" in diam and 14" deep into the end grain of a big log. Does anyone know of any tools or techniques to achive this?

You can never have too many logs.

Don't see why you'd need a hole that size, but also don't see why you don't try to keep it simple If I wanted to do that, I might just stab a chainsaw in, with several repeat cuts, and make a rough circle. Then hack it out with chisels. Or, get the largest bit I could find, and drill a batch of holes, and then use a chisel. Or, you could always use a section of pipe, set it on the end, and put burning charcoal in the pipe, and let it burn down. Or, if you had lots of time, maybe you could train termites to eat just the part you wanted. Or, you might be able to use a power post hold digger, don't really know how one of those would work on wood, but they seem to work OK in clay. Or, just make a large boring bit, and use it. Or, you could alway cut it off, then in half, and gouge out the center, and join them again. Myriads of ways to do it. Now that I think on it, I probably wouldn't do it at all.

JOAT Don't e-mail me while I'm breathing.

You might find a circle cutter large enough to do the outline, I'd consider buying or renting a power gouge like those used by log home builders to "dig" it out.

How about a large spoon bit and a LARGE drill...Hmmmm Maybe even a gas powered post hole digger. ;-)

-- "Shut up and keep diggen" Jerry

How about a 12" circle template and a plunge router with a 14" straight bit?

A really big lathe and a boring bar?

Drill a pilot hole, thread a bandsaw blade through it, and re-weld the blade?

Borrow some big chisels from a timber framer and go at it with a mallet?

I would use a router and a circular template or circle cutting guide and cut out a 2" deep circle to define your space. That's about as deep as you can safely go with a router (some bits may get you a little deeper, but it's no matter). Then I'd use a hatchet and chainsaw to remove what's inside the circle, going deeper and deeper. Stay clear of the walls, which you can rough out with a chisel if you want to keep the diameter consistent with the circle you defined with the router.

Good question. Timberframers or boatbuilders probably have a better way.

H.

Draw a circle on the end, take any 14" long drill bit you can find, whatever kind is cheapest or available, and drill out a circle of holes inside the drawn circle, and chisel out the rest. Same advice as others but without anything fancier than a cheap old drill. Keep in mind the width of the bit will be inversely proportional to the number of holes you'll have to drill to complete the circle.

You need access to a milling machine or a gun lathe.

Think this operation is what at one time known as trepanning and is performed in a horizontal manner.

The easiest way would probably be to clamp the work and use the power head to turn the cutting tool.

Considering the depth, may need to mount the work on a sled to handle the movement of the piece into the cutter rather than move the cutter.

You definitely need some major equipment to do this task.

HTH

Horizontal boring mill. I've seen them on eBay for less than $20,000.

LOL! Best one I've seen today.

I already gave one option, but I thought of another.

This one involves glueups but makes the cutting much easier.

If you make your cuts neatly and are careful with the glue-up, no one should notice that it's been dissected.

H.

I saw a HUGE lathe used to produce parts for an OTIS elevator a long time back in a newsreel. Handling a 12"+ diam log would be trivial. You couldn't afford the shop space I'd think.

Dan.