Today i called Craft Supplies and talked with a technical rep and explained to him that i have a supernova-2 chuck with spigot jaws (pic below) that will hold a tennon up to 2 1/4. I explained to them i do put a dove tail in the tennon and the serrations seem to grip very well when i secure the tennon in the chuck. I explained to him about me tearing the tennons and he said the same thing as someone else in the previous thread - probably alot has to do with the wood im turning (some of which is douglas fur, pine,
hemlock) but i also have some mesquite,and burls.
So he suggested that a larger tennon would help alot with this (softer woods etc-).........and he suggested one of the following for the supernova-2chuck:
1). Bowl Jaws - 4" with 3 1/16 - 3 3/4 opening
2). Bowl Jaws - 5" with 4 3/16 - 5 opening
3). Powergrip Jaws with 3 - 3 7/16 opening
He said although they sell many different types of chucks etc - he personally uses a VicMarc with dovetail type jaws in expansion mode on recesses. He personally favored that way of turning. He strongly suggested either option 2 or 3 for the larger tennon and larger bowl turnings as i have the supernova.
With kids using the lathe also i have favored the spigot jaws (shark jaws some call it i think) because the dovetail does not have to be exact and the serrations really grip into the wood hard (see pine bowl pic below)......the tech said that using a standard skew at the same grind angle it will create a perfect dovetail with no problem.....that option 2 has no serrations for gripping just a well made dovetail is all that is needed.......option 3 is meant to do both - a short tennon with a dove tail or you can make it a bit longer and the serrations in the back of the chuck would grip down into the wood like i was asking.
My main concern is safety for the kids using the lathe and that i stop tearing out the tennons soft wood or not...........
Thoughts? Wondering which one would be the best choice here....possibly the Powergrip ? anyone using it now??