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Thread: Tennon problem - New jaws question

  1. #1
    Join Date
    Jul 2008
    Palm Springs, Ca

    Tennon problem - New jaws question

    Following up on the last thread about my problems with tearing tennons when turning alot of times. I have a SuperNova chuck with spigot jaws that i have and will expand out to 2 1/4" if i remember correctly. and down to 1.6" . Being that part of my problem could easily be the tennon is to small for turning the larger pc's 8" diameter to 16".
    I contracted Teknatool and asked for their opinion on purchasing another set of jaws that could accomodate larger turnings. The technical person said that the best he could think of to get is supergrip jaws and it would handle anything. The powergrip jaws contract from 3-3.8"
    Just wondering what other people think of these jaws or the idea of purchasing these jaws which from what i have been told will greatly help solve my tennon problem ?????????????
    Thoughts ??? thanks Dan

  2. #2
    Join Date
    Oct 2006
    ABQ NM
    Dan, I've got a set of the supergrip/powergrip (whatever they're called) jaws, and they are indeed big and stout. If you're planning to turn much big stuff, I think they're a good addition to the arsenal.

    I didn't mention it in your other thread, but in my limited experience, some bowls just don't want to be turned. I had a bowl a while back -- the outer core of a set -- that I broke the tenon off of at least three times while it was still green, and once or twice during the finish turning. (And I'd like to think I was not doing anything wrong in my attempts. I was following all the typical advice.) The bowl finally split in two right down the middle, confirming to me that it really, really didn't want to be a bowl. One other thing to watch for is that you're not cranking down too hard with the chuck. You can crush the wood bad enough to expedite a broken tenon if you overtighten the chuck.
    When the going gets weird, the weird turn pro. - Hunter S. Thompson
    When the weird get going, they start their own forum. - Vaughn McMillan

  3. #3
    Join Date
    Jun 2008
    Atlanta, GA
    What do you mean by larger? Your #2 jaws should be able to hold a 14" bowl in compression mode with no problems on a G3 chuck which is smaller than the SN2, per Teknatools. I would suggest waiting on getting larger jaws until you get a few more bowls turned. The larger the bowl the more it shows up any problems in bowl chucking/turning/finishing. IMHO you are better off turning at least a dozen smaller bowls before you get past 10". You will then have a better feel for whether you really need larger jaws then and which would be your best choice. As you turn more you may find your turning needs require smaller jaws. I have a SN2, G3 and a several sets of jaws including the PowerGrip. I have turned a number of bowls larger than 12". But I turn more smaller work and tend to use the 25 MM jaws more than the Powergrip. YMMV.

  4. #4
    I'm in Mike's camp. I have a SN2 with the stock 50mm jaws and have used them to turn bowls up to 15" without issue. I've only broken one tenon in 4 years of turning, and that was my own fault (bad wood). As long as you have a good clean non-tapered tenon and a flat shoulder, it shouldn't give you any problems. If you're flinging a lot of bowls that are smaller than that, larger jaws may not help.

    I also have the Titan chuck and Powergrip jaws, but just haven't felt the need to use them yet. I've got a monster cherry blank I may try them out on.


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