any advice on tenons?

[Bob Bachynsky]

Hi all,
Just thought I'd see if anyone has any tips on making tenons easier. I'm pretty new at this but it seems like no two of mine are alike lol. Sometimes I nail it and my project stays on and steady other times i feel like I'm picking my piece off the floor a half dozen times. Are there any tricks, maybe a jig or something, to help a newbie make good tenons?

[John Keeton]

It may be helpful to know which brand of chuck you are using?

[Bob Bachynsky]

I have a Barracuda 2 (PSI). Same style as a nova for the most part although it doesn't have the dovetail angle.

http://www.pennstateind.com/store/CS...zCkxoCy0Lw_wcB

[Peter Blair]

Bob. Check out this thread
https://www.youtube.com/watch?v=5KHkkws9lWA
Reed Gray does excellent videos.
Wish he was doing them when I started turning.
Would have saved me a bunch of time on the old 'learning curve'!

[Peter Fabricius]

Bob, there is a UTube video by Mike Peace and he goes through all (?) the possible methods of "work holding" I think that is the title of the video.
Normally for your Profile style jaws the tenon should be about 3/8" long and a "slight" taper / dovetail will not hurt, it might improve the hold. Just be sure the work piece is seated against the face of the jaws and DO NOT bottom out inside the back of the jaws. Tighten the jaws occasionally to make sure they are not working loose, especially in softer woods.
If you are loosing your work across the shop floor it is possible that you are taking too deep cuts or you are getting catches??? Review your tool presentation with a mentor and always stay out of the line of fire.
Peter F.

[Thom Sturgill]

I had a lot of problems with the Barracuda chucks when I started. There were two issues - me and the jaws. Learning to get the tenon face FLAT and making the tenon shallow enough to not bottom out is important. The other was swapping the default jaws for the optional dovetail jaws PSI sells. The default jaws have two small ridges on the inside. They are just not deep enough to get a good bite, IMHO.

[Dan Forman]

I think I can see the source of your difficulty in the pic in the link you posted. This is a takeoff on the Oneway profiled jaws, however there is a big problem here, as they have omitted the primary characteristic that makes the Oneway jaws so successful. If you go to this link, and click on the zoom icon, and compare the geometry of the jaws interior surface to that of the Penn State jaws, you will be able to see the difference, and what Penn State omitted on their version, which may be a patent issue. Oneway Talon Chuck System - Rockler Woodworking Tools

The Oneway jaws have two relatively flat sections milled into the interior face, which allow for a very firm grip on the tenon. These do not seem to be present on the Barracuda jaws, which appear to be just milled in a circular fashion. This means that unless the tenon is cut to the exact size of the jaws, the jaws will only be able to make contact with the tenon on the very corners, giving a very small surface area of grip. Even if you could manage to cut to exact size, the wood would compress and become loose eventually, and if turning green wood, you would have to return the tenon after it dried, and it would no longer hold.

The Oneway design has a much greater grip area and thus holding power, regardless of the tenon size. Dovetail jaws have the same limitation - only contacting the tenon at the jaw corners, but because they are dovetailed, they will have more holding power than your Barracuda. If you want to keep the chuck you have, and keep pieces on your lathe, I think you will have to exchange the profiled jaws to dovetailed jaws. If you like the idea of making straight tenons, I would highly recommend the Oneway Talon with their profiled jaws. You will find they are a world apart from the jaws that are currently on your chuck.

Here are a couple of photo's to illustrate.

The first is what I would expect a tenon coming from your chuck jaws to look like, (only paying attention to the pencil marks). I suppose in reality they would actually be a bit farther apart. The second pic is the same tenon from my Oneway with the jaw marks highlighted in pencil. You can see that no matter the size of the tenon, they will have a lot of contact area, and hold quite firmly.

Dan

[Michael Mills]

I don't know of many jigs. The video by Reed Gray (ref Peter Blair) shows laying out a tenon or recess using divers which a lot of people do; this is about the 7min 30 second point.
Here is the link to the video referenced by Peter F by Mike Peace. If you haven't watched it already, it is worth the time (about 1.5 hours); at about the 1 hour, 5 minute point he shows a "go, no go" jig which is the max and minimum for each set of jaws. Similar to a set of open end wrenches.
https://www.youtube.com/watch?v=aUXil-5dEeo

Terminology may vary for the jaws. For me the "face" is the interior/exterior which tightens against the wood, the "top" of the jaws are what seats against the wood. The top of the jaws should sit flat and tight against the work. If the curve of the bowl continues all the way to the tenon then it can rock and not be supported making it much easier to orbit. IMHO this fit is more important than the fit of the jaws size.
In Mike Peace's video above he shows this about the 59 minute point.

Before everyone screams I do think the fit of the size tenon to the jaws is also very important. If you only have one set of jaws you may need to make the tenon 3/8" larger than optimum for the initial turning in order to re-true it for final turning. I have different jaws so I may cut the tenon to optimum size for 70mm on rough turning and resize down to 50mm for final turning. This allows a complete grip for each turning.

Another group of excellent video's which are about 10-15 minutes each are by Stuart Batty. Look for the ones on chucks, tenons, recesses, and similar...there are three in this group of about 35. He is very detailed as to how and why.
https://vimeo.com/woodturning/videos...rmat:thumbnail

[Reed Gray]

I think it was on a Glen Lucas video where he had marks on his tool rest for tenon sizes, very efficient. There are many ways to mark them. Most of the time, I think there is not much of a trade off with a 3 inch tenon that is grabbed by jaws that close down to 1 1/2 inches. However, you have to be more delicate in your cutting, and no catches. Over sizing is necessary in twice turned bowls, or you have to have multiple jaw sets to cover every situation.

robo hippy

[Bob Bachynsky]

Great! You guys have given me plenty to look at and I will (plus a couple of youtubers I hadn't stumbled across yet). Thanks so much

[Thom Sturgill]

Capt Eddie also has a video, but the main thing is his go/no-go gauge for sizing the tenon or recess. If I remember correctly, it simply a notch on one side that the tenon should fit into giving the maximum opening for the jaws and the maximum depth without bottoming out. The other side is a 'tenon' of minimum width and maximum depth for recesses.

[Mark Greenbaum]

I just watched Robo Hippy's video, and learned quite a few new things. Thanks.

[robert baccus]

Or just buy a bottle of thick CA!!

[nelson lasaosa]

Hi Dan,
Excellent tec review , and for us newbies a free tutorial. Thanks !

[Dan Forman]

You're welcome.

Dan