In reading another thread discussing jaws I wondered what other’s favorite chucks/jaws are for coring really large blanks.
I have the Nova Titan with deep grip jaws - they expand to about 5 1/2” but at that expanded width it is not an ideal hold since the jaws are opened so wide. I have used them many times for 18-22” bowl blanks without problem but recently had an issue. I was coring a 23” very wet blank that was a bit deeper than I’ve ever done before (about 14-15”) and the strain must have been too much as the edges of my tenon kind of crumpled or broke down when I was making the last and largest core, causing the piece to come a little loose and wobble and I had to redo the tenon and take down a lot of the depth of the blank.
For the first two smaller cores I had tailstock support using an extension, but for the largest core it wouldn’t reach the bottom of the second to largest bowl due to the blank depth. I usually core from smallest to largest so that I don’t have to remount but maybe in the future I should just core the largest first then put a tenon on it and remount it to do the smaller blanks. That would let me keep tailstock support the whole time but is a bit inefficient.
While it could have just been the wood (cottonwood which is relatively soft) combined with the heaviness due to it being super wet with a large and deep blank, I wondered if a larger chuck would have helped, maybe with a 6” tenon where the jaws were closed enough for optimal holding.
I was looking at the Vicmarc site and they have dovetail jaws for the VM150 chuck that measure at 4.9”, 5.9”, 6.9”, and 7.9” when optimally closed. I only have Nova chucks now and wanted to avoid the expense of another chuck and different brand but maybe for coring it’s worth getting a Vicmarc as I don’t see anything larger for the Nova Titan than what I have.
I’m curious what others use for coring really large blanks or other advice on how to avoid similar failures.
Thanks, Tom
I have the Nova Titan with deep grip jaws - they expand to about 5 1/2” but at that expanded width it is not an ideal hold since the jaws are opened so wide. I have used them many times for 18-22” bowl blanks without problem but recently had an issue. I was coring a 23” very wet blank that was a bit deeper than I’ve ever done before (about 14-15”) and the strain must have been too much as the edges of my tenon kind of crumpled or broke down when I was making the last and largest core, causing the piece to come a little loose and wobble and I had to redo the tenon and take down a lot of the depth of the blank.
For the first two smaller cores I had tailstock support using an extension, but for the largest core it wouldn’t reach the bottom of the second to largest bowl due to the blank depth. I usually core from smallest to largest so that I don’t have to remount but maybe in the future I should just core the largest first then put a tenon on it and remount it to do the smaller blanks. That would let me keep tailstock support the whole time but is a bit inefficient.
While it could have just been the wood (cottonwood which is relatively soft) combined with the heaviness due to it being super wet with a large and deep blank, I wondered if a larger chuck would have helped, maybe with a 6” tenon where the jaws were closed enough for optimal holding.
I was looking at the Vicmarc site and they have dovetail jaws for the VM150 chuck that measure at 4.9”, 5.9”, 6.9”, and 7.9” when optimally closed. I only have Nova chucks now and wanted to avoid the expense of another chuck and different brand but maybe for coring it’s worth getting a Vicmarc as I don’t see anything larger for the Nova Titan than what I have.
I’m curious what others use for coring really large blanks or other advice on how to avoid similar failures.
Thanks, Tom
