Alternative to a Long Through-Bore
Instead of drilling the length of a long piece, route matching grooves into half-blanks, then glue up. September 28, 2006
Question
We need to bore a 1-3/4” hole through 30" and 48" long pieces of poplar. The blanks will then be turned and tapered, 4" depth to 3"depth, for some gas drilling jig. We've got most of the process figured out with the exception of the through bore - any ideas? We only need to produce a dozen so fancy equipment is not practical.
Forum Responses
(Solid Wood Machining Forum)
From contributor A:
If you need to glue the blanks up you could use a router and a core box bit to produce the hole by making the semicircular half on each side before glue up. Then while gluing up stick a 1-3/4" dowel through the halves and this will align them, and remove the dowel so the glue doesn't attach it permanently.
From contributor B:
We do it the way contributor A stated. And we have been able to do it in lengths up to 8+ ft. Tool up a shaper head and cut the semi hole out of the square 1/2 blank first. Then glue together. Mount in lathe and turn.
From the original questioner:
Thanks - that's what I was looking for, a simple solution that’s basically fool proof. Will I need to be concerned with putting a release agent on the centering dowel? Or do you find there is little need for it to remain after initial clamping?
From contributor A:
I wouldn't want to attempt to leave it in there in fear of it getting stuck. If you feel that you must for alignment reasons I would at least wax it well, or maybe put a couple of coats of lacquer on it. Just make sure it is slightly smaller than the actual hole or you may not get it out even if the glue isn't the culprit. You can always ream it out with the correct drill bit to clean it up after it is glued.
From contributor B:
We don't leave the dowel in the hole. We line up both ends with short pieces of dowel and then remove them. We then take a piece of 1/2" copper pipe and push thru a paper towel or rag to remove the glue squeeze out in the inside. It is kind of like cleaning a gun barrel.
