Chuck Basics

[Lyle W. Kerr]

Ok, I am back again.

I went to this last Tuesday's meeting, finally, for the Central CT Wood Turners and they were doing a demo that night on Christmas ornaments. Looked pretty easy, but I have never hollowed out anything and I have not had much luck with pieces staying in my Nova Midi chuck. The demonstrator at the end showed me how he sets up his pieces with a dove tail on the end and uses the corresponding jaws for that.

Well not sure what I am doing wrong but after making some pieces to practice on in the chuck, 3 went flying.

I got the bottle topper issue resolved with lots of help here and I am hopping some one can list some basic set ups when using a 4 jaw chuck.

Pictures would be great if possible. Thanks.

[Ryan Baker]

You need to cut a dovetail that matches the angle of the jaws as much as possible. The dovetail should not be so long that the piece hits the bottom of the jaws. It should make contact with the outer ends of the jaws and the dovetailed sides of the jaws -- not bottom out. The surface where the outer ends of the jaws meet the base of the blank need to be smooth and square, so there are no gaps at all between the blank and the jaws, all the way around. For the best hold, the tenon (or recess) diameter should be just slightly bigger than the diameter of the jaws when closed all the way. That allows the jaws to grip all the way around. If the jaws are opened way up, they only grip at the tips of each jaw.

How are your pieces going "flying"? Are they breaking off the tenon? Not having a good tight fit with the face of the jaws will almost guarantee breaking it off and sending it flying, especially if you get a catch.

A picture of some of your flyers would most likely reveal the problem.

[Bernie Weishapl]

Ryan hit the nail on the head. I helped the neighbor with his problem of flying pieces. He had the tenon so big the jaws were almost max'd out open. His shoulders weren't sqaure and his dovetails weren't really dovetails.

[Allen Neighbors]

When I cut a tenon for my SN2 50mm jaws, I make the tenon diameter as Ryan spoke of (I don't measure, I have a spur center that fits into the chuck and the jaws are nearly closed, and I cut the tenon on the chuck end of the piece, so I can see just how large or small to make it.) After cutting the tenon, I use the point of my 1/2" Skew and just scrape a tiny groove for the dovetail jaws to fit into... less than a 1/16", tiny, groove. Rarely ever lose a piece, and then it's because I was getting to radical with my cuts.

[Kyle Iwamoto]

Make the chuck tight tight tight.

The blank should also rest on the jaws. If the tenon is too long, it will have way less support. I found that out the hard way. Some make a shoulder for the blank to rest on. Try to use the tailstock as much as possible.

[Lyle W. Kerr]

I will see if I can get some pictures up today, I think I threw most of them in the fire last night. . . a little frustrated. :D

If I understand what you are saying, I think that is what the demonstrator said at the last meeting about how the dove tail should sit in there. My pieces were bottoming out in the chuck last night and I was about half way open on the jaws.

None of the pieces broke off at the base they all popped out when I was rounding over the end to start making the ball portion to practice hollowing it out. They were all about 4-5" long.