help for jaws on supernova 2

Ok, Let me clarify. I am a beginner with using chucks. I just got a supernova 2 that came with the 50 mm jaw set. It looks like the only way you use those is to cut a tenon and expand them out. Lots of you guys seem to grab the foot of the bowl from the outside. i am placing an order. will the 100mm jaws do that for me. I have a jet 1642 so will be turning item that may be up to 14" or so in diameter. Also when you clamp the jaws down on the foot will just 2 points on each of the 4 jaw quarters be touching the foot. I am also looking at getting the cole jaws. That will allow me to refinish the foot out when i am done... correct? What determines whether i should expand the jaws in a tenon or clamp them down on the outside of the foot? Is one more secure than the other. Sorry for all the questions but i want to get the order in to woodcraft for the free memorial day shipping. thanks for all the help. doug

There is no reason you can't use the standard 50mm jaw set as recess or tenon hold.
See page 11 to 13 on the manual:

http://www.teknatool.com/products/Ch...May%202004.pdf

Please pay attention in making good contact on the shoulder of your tenon. That is most of the strength of the holding power.

Learning how to use the jaws correctly is more important than getting another set of jaws. The Cole jaw has its limitation as well. It won't handle any natural edge bowl or certain shape bowl rim.

I would suggest you find a local club and have someone gives you some hands-on guidance. That would shorten the learning curve.
AAW Local Chapter Listing - The American Association of Woodturners

Doug,
Turning a tenon and using your chuck in the compression mode is the better way to go. You should size your tenon to be just slightly larger than your chuck jaws when they are tightly closed as this will give you the maximum holding power. If you will be turning your bowl "green" and letting them dry before turning them to final size than your tenon should be a bit larger to allow you to true it up and still be slightly larger than the jaws in their closed position.

I have not found cole jaws to be all that helpful but I'm sure that others here can tell you how well they like them. I have about a 14" tapered jam chuck on a dedicated face plate that I use for finishing bowl bottoms. I pad the jam chuck with a mouse pad and bring up the tail stock to center and hold the bowl against the jam chuck, turn the tenon off, finish the bottom and carve away the remaining nub by hand and sand.

When initially forming the outside of your bowl and turning the tenon be sure to bring up the live center and tail stock to make that dimple in the bottom of the tenon. This tiny centered dimple will not move if (when) your bowl warps on drying and makes it easy to center the bowl on the jam chuck for finishing.

Thanks for the response guys. I didn't get many instructions with the check itself so going to the manual download helped alot. Thanks again. doug

Doug, I have a piece of 1/8" tempered masonite that I made a template to size the tenons. It's shaped like a U with a handle at the bottom. The legs of the U are 2-1/8" apart. That's the size tenon I make for my 50mm jaws.

Doug, you seem to have "tenons" mixed up with "recesses". A tenon is a stub of wood sticking out that you clamp the jaws down onto. A recess is a hole in the wood that you spread the jaws into.

Thanks Allen, that sounds a lot quicker than getting the measuring tape and calipers out each time. thanks, doug

Doug I turn a tenon about 2" in diameter and make sure it is dovetailed. Tighten the chuck on it and you are good to go. I bought the 100 mm jaws and have yet to put them on. As was said above you are talking about a recess.