Deep Boring

Tom Storey

Member
Messages
12
Location
Qualicum Beach British Columbia
I’m going to ask this question on a couple of forums just to get ideas from a broad spectrum of woodturners.
Task: I must drill a hole about 10 inches deep + into dry walnut end-grain to start the hollowing process for an urn. I’ve not done this before and I’m a little apprehensive because, even when drilling pepper mills to a depth of 7 or 8 inches, I’ve had the drill bit drift significantly and that has caused severe binding, not as in constipation...well maybe that too.
What technique do the ‘deep drillers’ of whom I’ll soon be a member, use to bore deep holes into end-grain?
Thanks, Tom
 
Hi Tom. I'll let the more experienced turners jump in, and while 10" is mighty deep, I run the lathe at slow speeds, draw out the bit to get rid of waste, and continue to move the tailstock forward between cuts.

What size bit do you intend to use?
 
Do the drilling first. Your hole will become the axis. Therefore a little drift won't matter. I prefer brad point bits for this sort of thing. Do withdraw often to remove chips. You can get extensions but, still, 10" is a reach. If you plan to do this often, have a machinist weld an extension to a bit. You will then have a custom tool. I have a couple like that.
If you are really determined to not have drift, the old fashioned spoon bit works about the best there is. Makers of traditional muzzle loading rifles use these to drill the ramrod hole.
Have you thought about drilling only partially, turning out that part, drilling more, turning out more, etc.?
 
Drill from both ends Tom. If you have a 1/16" drift per inch and drill 10"...that's a 5/8", pretty bad. But if you drill from both ends, it's negated in the middle. It just dawned on me that you are doing and urn :doh:. I'll shut up now. :doh::doh::doh:
 
Tom I guess I am the odd man out. I don't drill my Hollow Forms. I just start cutting with my boring bar and hollow it all out. It was how it was shown to me and just never have drilled anything out except peppermills. If I did drill I would stop about a inch from the bottom and when you get there in the hollowing process the bottom should be ok and centered.
 
Removing the bit from th4e work frequently to release the chips. If you don't the bit will bind in the work piece.

This is a for sure....DAMHIKT... I jammed a spade bit in a peppermill blank by not backing out soon enough.... almost lost both the bit and the blank.. took over an hour to dig enough wood chips out of that blank to finally get the bit out... BE SURE YOU BACK OUT EVERY INCH OR SO TO CLEAR THE HOLE.
 
i use an auger held in a pair of mole grips (locking plyers) i've drilled 18" like this with hardly any drift- just remember to stop every inch or so back up and clear the swarf then carry on drilling etc
 
I generally use a Forstner type/sawtooth bit on the lowest speed on my lathe. That last one I did was a 2" hole in Milo. I went about 4" deep but as good as it was working, I could have gone deeper if the wood was longer. I keep the chips blown out with air and back the bit out about every inch or so. This allows the bit to cool a little too.

I have not had any wandering using the Forstner bits, as long as they are sharp.

Aloha, Tony
 
I too do not drill when doing hollowing work, (Why?) always seemed like a waste of time to me. If you insist on going that way. You could use it as a referance point and a "get started" hole as from that point on the process is simple and to the point. I
 
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