Jaws for Stronghold Chuck

[Tom Bucanan]

I have a Stronghold and the #2 jaws that came standard with it; however, I have decided that I need a larger set of jaws. When I am coring bowls (about 14 in and larger) The tenon often shears right off. I think this is because the tenon needs to be larger; however, the chuck is maxed out. I would like to begin coring bowls that are up to 18-19", so....

Which set of jaws should I get? Should I get the #3, #4, or the 'Tower Jaws?' (What is up with the Tower Jaws?)

-Tom

[Tony De Masi]

Tom, I move up to the #4 jaws for the larger bowls which have tremendous holding power.

Tony

[Leo Van Der Loo]

Hi Tom
I use the #3 jaws as the #4 are just new now, but another thing, I use a recess to hold the large bowls, it is stronger than the tenon hold, never shears off :-))
I've used the #3 for bowls up to 28" and the biggest problem I run into is not the hold of the chuck, but the flexing of the wood itself.
Next time you have a tenon shear off, remount and cut a recess, you'll find it will hold just fine, but the larger jaws will help to get a stronger grip for sure.

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[Tom Bucanan]

How do you re-true a recess after the bowl has dried and warped?

[Leo Van Der Loo]

Depends a bit on how bad the bowl has warped, if I am unable to hold in the jumbo jaws, I will first hold in the recess as it is, and straighten the rim some, then hold in the jumbo jaws and true the recess, you could also use the vacuum chuck if you have one, I Do but don't use it very often.
I find it easier to use the jumbo jaws most times, when the recess is true, I finish turn the inside and the rim and outside some or all, depending on size and shape, and if needed flip the bowl over and finish turn the outside and the foot.
sometimes I will leave the recess so I can sand and finish some more later, if that's not needed I will finish the foot the first time.
You have to be flexible in what you do/use, shapes and sizes etc are always different, (for me anyway), and you have to apply what will work best.
There are times I have a lot of plastic tape to help secure the bowl, or cling wrap (the packing stuff) better safe than sorry ;-))

[Jim Becker]

Just remember, with a recess, you have limited wood to support the force of the expansion with a bowl form than you do with something like a platter.
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OP, If your tenons are shearing off frequently, it's not necessarily the jaws, although it could be because the tenon is too large for the "sweet spot" of the jaw set you are using. (#2 jaws fully expanded leave little jaw in contact with the tenon...) Be sure that your tenon is not bottomed out in the chuck and that there is a shoulder on the form that the top of the jaws rests on. Without both of those things to be true, combined with a tenon that is sized appropriately for the jaws, breakage and/or flying forms are bound to happen.

Although I use the smaller Talon chuck, I have the #3 jaws to support larger pieces so I can use a bigger tenon and get it "right sized" for the chuck. If I need larger, I'll get a Stronghold with #4 jaws at that point.