# Supernova2 chuck problem



## Domenic Dinezio (Aug 5, 2014)

Hey guys, its my first post and I have an important question that I cant figure out. I am new to turning and bought a jet lathe, and a supernova2 chuck and some sorby/crown chisels. Anyways on Saturday I was in the wood shop and I decided to try out my new chuck. Before I put on my supernova2 chuck, I roughed down a small (6in Diameter) piece of pine I had laying around. After roughing, I made about a 2 inch tenon to fit in supernova2 jaws (my jaws are 50mm so about 2 inches.) So I attached the supernova 2 chuck on and inserted the pine and tightened down the chuck jaws. I set the lathe on slow (my jet lathe speed is set from 1-10 (1 being the slowest)). I grabbed my bowl gouge to try to hollow it out some and all of a sudden the piece goes flying off lathe. Luckily I was standing to the side. Anyways this happened another 2 times before I decided to stop and do some more research. Anyways any help would be APPRECIATED. The only thing I can think of is the worm screw but all the videos I watch on youtube, it doesn't look like anyone is using that piece. Maybe the jaws are faulty? I tightened the jaws down realllllly tight to the point where I could feel the wood compressing. Please let me know your opinion and again any help is really appreciated.
thanks and sorry for the long post.


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## bond3737 (Nov 13, 2009)

first you wanna make sure you are making a proper tennon which with the 50 mm jaws I think its 90 degrees and not dovetailed at all then when you tighten the jaws there should be a gap between the bottom of the tennon and the jaw face. You want to make sure the top of your tennon is seated FLUSH to the top lip of your jaws then wrench it down real tight and you are ready to roll... Also check out a bunch of vids on tool orientation It's incredibly important. Make sure your tools are SHARP- also very important and finally turn your speed up some. no need to be at a 1 with a piece that small the slower you go the harder it is to make a clean cut. Make a few test runs and stand to the side in case it flies off. If you are confused about terminology or anything like that take a few pics of how you have it set up and this will help us see what may be going wrong. Im guessing though that it is the way you have your tennon seated in the chuck or its not tightened enough or the tennon is not made correctly... hope that helps, happy turnin, 
Bond


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## bond3737 (Nov 13, 2009)

Oh WELCOME!!! btw... this forum is great lotsa knowledgeable folks on here.... Almost forgot... Grain orientation is also very important. For a bowl gouge you want to be cutting into side grain and not endgrain. If you plow into endgrain with your gouge in the cutting position you are bound to get a catch


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## john lucas (Sep 18, 2007)

If it's coming out that easily then your doing something wrong with the bowl gouge. There could be other factors of course. The tenon needs to be larger than the jaws when they are fully closed. In other words there should be a little gap between the jaws when they are clamped on the wood. 
As Bond said the tenon should be shorter than the height of the jaws so that the wood outside the tenon will sit squarely on top of the chuck. This keeps the wood from rocking in the jaws. 
Not sure what your saying about the worm screw. The worm screw is usually used without a tenon. It goes in the jaws when they are fully closed down on it, and then it is screwed into the wood. The outside of the bowl is usually turned this way along with the tenon for the bottom. Then the worm screw is removed and the bowl is reversed for hollowing the inside.
I usually never use the worm screw. I prefer to start my bowls between centers using a drive center and my live center in my tail stock.


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## NCPaladin (Aug 7, 2010)

As Bond stated, the 50mm jaws call for a straight tenon. Attached is a pic of the jaws with a square. There is a small lip at the top to bite into the wood and the balance is straight. I normally make my tenons about 3/8 long.
The top of the jaws should sit flat against the work piece.
I also suggest three short video's by Stuart Batty found here..
http://vimeo.com/woodturning/videos/page:1/sort:alphabetical/format:thumbnail
They are very detailed and should come up in alphabetical order. The three are:
Jaws & Chucks
Recess Tenons & Preparing Recesses
Tenons Part 2


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## DonAlexander (Apr 12, 2012)

Dominic, I feel your pain. I am fairly new to serious wood turning, too (I've done a bit of it off and on for 30 years, but never seriously tried to understand it). Last week I bought a SuperNova 2 and turned a tenon for a blank I intended to make into a decorative 'wine glass' out of some cherry I laminated. It flew out of the chuck on my first couple of tries, too. Chucks looks so darn easy on the YouTube videos! I too wondered if I had a defective chuck (50mm just like yours). I thought about it and remembered hearing or reading of the importance of the shoulder on the tenon. 

The shoulder needs to ride *flush* with the jaws. When you think about it, that shoulder adds a tremendous amount of stability to the mount. The jaws can only hold so tight as they grab 1/4" of wood on a 6" long cylinder. When you work pushing a tool into the wood away from the jaw there's a lot of leverage at work. The shoulder provides a bearing point that helps keep the wood from prying the jaws open. So as Bond said, you need a *proper* tenon.

Once I sorted that out, the chuck held the wood a lot better...but not perfect. My technique with the bowl gouge was pretty clumsy, which isn't too surprising since I only heard about bowl gouges within the past month. I found it worked best to take very shallow cuts and to really think about how I presented the cutting edge to the wood. So I think John Lucas is probably right also about technique being important. 

I'm looking at all of this as learning exercises to understand the tools, the 'sweet spots' and the limits of both tools and techniques. And frankly, I've learned a lot over the past couple of weeks. ...and the 'wine glass' isn't worthy of posting a photo but I will say my wife was rather surprised when I brought it upstairs. I believe her first three comments were, "You made that?!" in somewhat disbelief.<g> 

Now I've got a question about a problem I have with the spindle gouge and will ask if I can't figure it out and I can figure out how to ask it. Oddly, I saw Tim Yoder have the same problem in one of his YouTube videos...and can almost see the cause...but not quite.


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## Domenic Dinezio (Aug 5, 2014)

Thanks guys, already really informative. I'm going to give it another go this weekend. I think my problem is the tenon not being flush. But I was messing around with the chuck earlier and it seems like the jaws loosen up fairly easily, but again maybe its because the tenon isn't flush. I will post again with my progress on Friday and hopefully with some pictures. thanks again guys.


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## NCPaladin (Aug 7, 2010)

Domenic Dinezio said:


> But I was messing around with the chuck earlier and it seems like the jaws loosen up fairly easily, but again maybe its because the tenon isn't flush.


The jaws do have some movement (wiggle room) until they are tightened.
If you are turning green wood you need to stop and check every so often as the wood will continue to compress. With green bowls I probably check 2-3 times and I normally can tighten them a little each time. Once tightened the jaws should not loosen by themselves.
You did not say how deep the bowl is; the deeper it is the more leverage is applied to wedge it out of the chuck. I believe Nova states 6" maximum depth/length with the 50mm jaws.
On page 21 they also suggest a spigot (tenon) length of 5/8". I usually go 3/8 -1/2.
http://www.teknatool.com/products/Chuck_Accessories/General/downloads/Accessory Jaw Manual_Nov07.pdf

If/when you have the time this is a very good video by Mike Peace on almost all holding methods. The wormwood screw is about the 1 hr 5 minute mark and you should be able to slide over to it. Total video is about 1.5 hours.
http://www.youtube.com/watch?v=aUXil-5dEeo


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