Nova2 Chuck Problem

[Michael Short]

I recently purchased a Nova2 Chuck with 50mm jaws and have been having trouble getting it to grip a tenon.

Today I purchased the 25mm jaw set and with a 1" piece in the chuck, I bearly touch the work piece and it starts to work it out of the chuck.

If I do a recess in a piece for a bowl it seems to work fine for outward pressure but I can not get the chuck to hold using the compression on a tenon. Any one else have this chuck having the same issues? I am at a loss on this one, any suggestions? Thanks.

Mike.

[Ken Fitzgerald]

Michael,

I use a SN2 chuck and haven't had any problems. I use it got grip tennons on bowls and HF without any difficulties. IIRC you don't want any flare to the tenons...they should be straight not dovetailed.

[Ken Fitzgerald]

Michael,

Another thing to watch out for. Your tenon should never touch "bottom" or rather bottomout within the jaws of the chuck. You want to grip the tenon and the pressure of turning is actually applied to the area where the outer surface of the jaws meet the "shoulder" of the bowl.

[Michael Short]

Thanks Ken. I am using a straight tenon and the length of the tenon is the same as the jaw depth. I am just trying to hollow out a 1" stock piece for making a small bird house and the as soon as I touch with very little pressure the end the piece starts to work out of the chuck. Thoughts on a defective chuck?

[Ken Fitzgerald]

Michael...it's possible....Try shortening your tenon a little to make sure it's not bottoming out. And make sure that the outer face of the jaws have a good surface to rest on where the tenon meets the work piece. I have turned some things where I only had a tenon about 1/8-3/16" long and didn't have the problem you are experiencing.

Good luck!

[Gordon Seto]

Michael,
It sounds like you need some instructions on using the chuck. The SN2 has dovetail jaws (not straight tenon). As Ken said, the length of the tenon should never bottom out. The shoulder sitting on top of the jaw is what gives you the holding power, not the force alone. You should cut the tenon or recess with clean intersecting corners roughly matching the shape of the dovetail. The size of your tenon or recess should be as close to the diameter of your closed jaws. That way you will have larger contact surface rather than just the 2 corners of each jaw digging in crushing the wood fiber.

[Don Carter]

Michael:
I use the SN2 with no problems. Have you been having the problem all along (before the new jaws were installed)? Did you install the jaws in order by numbers 1-4? It seems strange that it would hold on the recess and not compression.

All the best.

Don

[Leo Van Der Loo]

Hi Michael.
Maybe you are using the wrong type of jaws, I never have problems with holding pieces like for bird houses, mind you I do drill them out first, than complete the hollowing with a tool.
Here's the jaws I use for holding smaller stuff and the other ones for larger.

[Don Carter]

Leo:
Not to hijack Micheal's thread but, do you use the spigot jaws with serrated jaws or the smooth ones. I think the Oneway jaws will fit the SN2 chuck, do you know if that is correct? I am thinking of ordering Oneway spigot jaws for my SN2 chuck.
All the best.

Don

[Bernie Weishapl]

Gordon hit the nail on the head. Don't make your tenon to large. I make mine no larger than a 1/4" bigger than the jaws when they are fully closed so that you have full coverage of your jaws on the tenon. You need a dovetail on the SN2 the same as my Vicmarc.

[Andrew Derhammer]

If the jaws are smooth you need a dovetailed tenon.

Nova also sells spigot jaws with serrated teeth designed to hold a straight tenon.

[Michael Short]

Ken -- I tried the shorter tenon. I was using 1/2" in length and shorten to 3/16" to no avail.

Leo -- I have the 50mm jaw set and the 25mm set, both are smooth. The 50mm has a dovetail, but the 25 mm looks to be straight.

Gordon / Bernie -- On the 25mm set about 1 inch in diameter I am using about 1/2 to 7/8 inch diameter. I will have to try a smaller diameter tomorrow and let you know if that solves it.

I talked to a guy in the local turning club that does alot of tenons and he is going to stop by tomorrow evening and see if it is the tenon, the chuck or me that is the issue.

Thanks for the input. I will update you on what I find out tomorrow.

[Wayne Kuhn]

I typically turn my tenons as large as the jaws will accept, this allows me to turn the tenon round again after drying (and warping.)
When you turn your tenons to the minimum diameter, do you have enough to turn the tenon ropund again after drying?
I have had no problems with my method.

[Jeff Nicol]

Mike, Does each jaw have one screw or two screws holding it to the body of the chuck? I have noticed that if there is only one and with the small jaws gripping to tight can flex the jaws and not hold well at all. If you could post pictures of what you have then we can make a better diagnosis. How long is the piece of wood that you are using to make the bird house? If it gets out there to far the leverage created could cause you trouble also. If the wood is green/wet the smooth jaws don't hold so good either. One more thing the dovetail should be as close to the dovetail on the jaws and the face of the jaws should touch the wood on the flat or relief of the blank. If the jaws have nothing to seat against it will tip and come of like it is doing. Here is a quick diagram.

Hope it helps,

Jeff

[Michael Short]

I asked a guy from the local woodturning club by tonight to take a look at what I was doing.

He looked at the tenon and told me is cut correctly and fitting into the chuck properly. Jeff - Thanks for the posting the pics of this as well.

The guy told me that with the straight smooth tenon that I would have trouble holding the stock in place. He suggested that I get a set of serrated jaw like Leo had pointed out or a smooth set with a dovetail on the inside at the very least, he recommended the serrated type.

One person suggested whether the jaws were one or two screw held. They are one screw per each jaw and we did notice the flexing as suggested. Thanks for that information. Thanks for pointing that out.

All in all the chuck is fine it appears that I made a bad choice for jaws for what I am trying to accomplish. I will be heading to woodcraft tomorrow for a different set.

Thank you to all that responded with great input and examples I appreciate it.

[Steve Mawson]

Sounds like you are making progress. Hope the new jaws do the trick. I have two Nova chucks but have not had the problem you describe, probably just lucky. Still not to say that once in a while something does work loose or gets launched.

[Gordon Thompson]

shoot.....i'm having the exact same problem with the 25mm jaws.

i can't get them to hold the tenon. the work, works out almost immediately.

was your problem solved with new jaws?

did woodcraft let you return used jaws?

thanks...

[Ken Fitzgerald]

Is it possible that those jaws were made to go inside a recess rather than grasp a tenon?

[Mitchell Cholewinski]

Michael Short
You have gotten good advice here and I want to add my suggestion. One thing I didn't see that anyone suggest here that you must do if your using wood from the woods. You need to square the face of the wood before you turn a tenon,when you use store bought wood the face is already square. Square the faces, Turn a tenon between 1/4"and no more than 3/8" long,dovetail the tenon and then you do want to bottom the tenon out up against the bottom of the tenon, your jaws are 1/2" deep so your never going to hit the bottom and skew the fit in the jaws. Do this right and your problems are history. Mitch

[Allen Neighbors]

Don Carter: No. The Oneway jaws will not fit the Nova SN2 Chuck.

When I turn a tenonfor my 50mm jaws, I make the tenon 3/8" long (it won't bottom out on the jaws), and make the sides straight with a sharp corner, and a good flat, so the outer surface of the jaws will sit flat and evenly.
I then take my small skew, and make a shallow, pointed groove around the tenon (right next to the shoulder) about 3/64 of an inch wide, for the dovetail on the jaws to grip.
I should add that I do this on hard wood. On soft wood, or green wood, I don't make the little groove.
Works well. I hold forms for hollowing that way.

[Leo Van Der Loo]

Sorry Don, I never saw your question, I don't know if the Oneway jaws do fit a Nova chuck, I have 3 Talons and one Stronghold chuck, and just use what I think will work best, I have all the jaw sets and a couple double, I would not consider buying a nova chuck, there have been to many problems with the novas, and I consider the Oneway chucks much better quality, yes they are more expensive, I guess you get what you pay for.

[Mike Peace]

I am confused. My SN2 uses two screws for each of the 50mm jaws not one. The smaller 25mm and 35 mm jaws use one screw. You did not mention the size of your bowls.

IMHO, I do not think the issue is one of chuck quality. I find that most folks tend to like the chuck they have and I guess I am no exception I have a SN2 and a G3. I have no problem with the Nova 50mm smooth jaws with the dovetail design holding bowls upd to 12-14" with either Nova chuck.

I do have a set of Nova spigot jaws with serrated edges but they are designed for gripping a tenon of end grain like the end of a log for hollow forms. They are good for what they are designed for but I would not use them for a bowl as they will scar the tenon more than a smooth jaw and are more likely to crush and cause a tenon failure on a typical face plate type bowl.