Couple of questions

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Forum topic by Gixxerjoe04 posted 06-25-2014 04:12 PM 799 views 0 times favorited 8 replies Add to Favorites Watch
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833 posts in 998 days

06-25-2014 04:12 PM

I’ve been turning for a full 3 weeks now and got a question about using a chuck. I got one off psi, seems pretty decent but def not top of the line. I’ve made a couple small bowls and made tenons for them but wasn’t sure on the size they needed to be but was told a little bigger than the jaws closed all the way, is that correct? When hollowing small bowls it’s work pretty fine but it’s caught a couple times and became wobbly, is that normal? Had to take it out and retighten it and just hope it didn’t do it again. Tried a longer vase and made my tenon too big and my jaws kept coming loose so had to redo it, found it odd it would loosen like that, luckily it didn’t come flying out. So what’s proper tenon size, barely bigger than jaws closed and long enough to touch the bottom of chuck?

2nd question is about turning thin plate bowls etc. I bought some blanks from a website that are probably 2.5-4 inches thick. Figure making a tenon would take an inch or so away so you’re left with one tiny bowl or whatever. Is that how you all turn thin stock or another way? Saw a video from captain eddie where he glued the bottom to a wood faceplate he made but that just seems like it would have a good potential of coming off but don’t know since I haven’t tried. How do you all do it? Don’t know anyone who turns bowls or larger things to ask so figured
I’d ask the experts.

8 replies so far

View Mike67's profile


97 posts in 2757 days

#1 posted 06-25-2014 04:47 PM

Yes, the circumference of the tenon should be just large enough for your jaws to grab when fully closed. It doesn’t have to be perfect, but get it close. I assume your chuck has serrated jaws (like the PSI chuck I got some years ago) rather than dovetail jaws. The height of the tenon should be enough to reach the serrations on your jaws but not enough to bottom out in the jaws. You also want to leave a flat area on the outside bottom of the bowl around the tenon where the top edge of the jaws will contact the bowl. That should give a pretty solid grip. However, a good catch can break a tenon. My PSI chuck has only let go of bowls when a tenon broke. Otherwise, they stay in there. Even when you have a good tenon, periodically checking that the chuck is tight is always a good idea.

As for the shallow bowls, you can use a glue block safely. Just make sure you clean up the mating surfaces before gluing and give it time to cure. Another method is to use a mortise on the bottom of the bowl into which you can expand your chuck jaws. The mortise should be deep enough to get the serrated part of the jaws in, and should have a slightly larger circumference than your jaws when fully closed. The challenge with this method is remembering that you have less wood thickness at the bottom when hollowing.

And some encouragement – turning can be a bit frustrating at first but as your skills improve, you’ll have fewer and fewer catches. Keep at it.

View Frank's profile


40 posts in 3084 days

#2 posted 06-25-2014 05:02 PM

Well it has been several years since I last turn anything, but from what I remember, the tenons should be long enough to seat flat on the bottom. The size can be anything that fits in the jaws either, in or outside, depending on what you are doing. If you get a catch, yes, the work can be pulled out or skewed. This is why you should always wear a face shield. Just reseat it, tighten the jaws, and go for it.

Glue blocks work fine, although a catch can pull them off too. You should always try to work between centers as much as possible.

Have you check to see if you have a turning club near you? It is a great way to learn for those with experience. The club I used to belong too, had a mentor program and would pair up new turners with experienced ones, so they could learn.

-- Some rescue cats, some rescue dogs. I rescue tools. Feel free to send me any tools you cannot take care of or don’t want and I will foster them until I find a good home for them.

View Gixxerjoe04's profile


833 posts in 998 days

#3 posted 06-25-2014 06:19 PM

Thanks for the info, there is one around here that meets once a month, meant to go to the last meeting but forgot about it.

View dirtycurty's profile


44 posts in 1000 days

#4 posted 06-25-2014 08:36 PM

I have only been turning for 5 or 6 months now and just got my first chuck which is a PSI chuck about a month ago. Previous to the chuck I did all of my bowls between centers and with a glue block with a face plate mounted to it. To understand the reason for making your tenon a little bit larger then your jaws at fully closed position do this little experiment. Take a scrap piece of ply wood or something relatively thin and cut it out with a bandsaw, scrollsaw or jigsaw the diameter that is just a little bit larger then the closed jaw diameter. Then cut another piece the diameter at which your jaws will grip it with the jaws fully open. With the smaller disc of wood in the chuck look at how much of the jaws contact the disc. Take the larger disc and put it in the jaws and look at the contact of the jaws to the wood. You should see that with the jaws opened up there is very minimal contact between the jaws and the wood mainly only on the inside corners of the jaws.

Catches are really hard on any way that you mount the wood but the more you practice and turn you will get less catches. Don’t think you will get the point where you will never have catches because that ,more than likely, will never happen. Expert turners and professional turners still get catches once in a while.

If you have access to a bandsaw, cut your blanks round, this will help with less time sharpening your chisels and will help with less stress on the chuck jaws. When start with a blank find the center on both sides. Mount the blank between centers and turn the blank round, rough out the outside shape, and make a tenon. Install the chuck and mount the blank to the chuck using the tenon. Using a live center in the tailstock, bring the tailstock up to the blank and tighten it up to blank. This will help the jaws support the blank. Hollow out the inside of the bowl as much as possible. When you have as much of the wood as possible removed (I like to think of it as extra weight) you can remove the tailstock, remove the piece of wood that is left in the center, and finish your bowl. This method can also be used for a vase but usually a vase requires the use of a steady rest to properly support it while turning.

View gwilki's profile


119 posts in 895 days

#5 posted 06-25-2014 08:44 PM

When you talk about your plate blanks, you say that you will lose 1” for the tenon. The tenon only needs to be 1/4” long, max. You never want the tenon to bottom out on the jaws. The grip gets much of its strength from the face of the jaws being flat up against the bottom of the bowl. Go onto the Oneway site and watch their videos about turning a tenon. You don’t need to have a Oneway chuck for their instructions to be worthwhile.

Also, if your are turning any wet/green wood, remember that the tenon will shrink as you turn the bowl. Stop the lathe and tighten the chuck frequently.

-- Grant Wilkinson, Ottawa ON

View Gixxerjoe04's profile


833 posts in 998 days

#6 posted 06-25-2014 10:54 PM

Well I guess it’s a half an inch, to the bottom of the chuck. I’ve got carbide tools from captain eddie, pretty good stuff compared to nothing else since I haven’t used traditional ones haha.

View TheDane's profile


4938 posts in 3084 days

#7 posted 06-26-2014 01:54 AM

”... the tenons should be long enough to seat flat on the bottom.” I would not do this. The shoulder of the tenon needs to fit flush against the rim of the jaws. If you bottom the tenon out by making it too long the rim of the jaws may not get a firm grab which is a sure way for the piece to come off the lathe at an inopportune time. I seldom make a tenon more than 1/4” long.

-- Gerry -- "I don't plan to ever really grow up ... I'm just going to learn how to act in public!"

View Gixxerjoe04's profile


833 posts in 998 days

#8 posted 06-26-2014 02:59 AM

I posted some of my first turnings in the project section if anyone would like to look at beginner work haha. I really want to do bowls and vases for some reason. Think they look good and all but would like to figure out what sells so I can hopefully work on stuff that won’t just sit in my house or shop. My fiance thinks no one will buy a bowl or vase for some reason so I dunno. Thought about making deer calls, i hunt and a nice looking burl grunt call would be cool.

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