It's now a shorter bowl

[Lawrence Tarnoff]

My 10" diameter by 4" deep bowl is now shallower thanks to a recess that failed to hold and a tenon that did likewise. Cut a new tenon and am proceeding to hollow the bowl. A few dings from its ride on the shop floor, but I am learning. Too cold to turn here til maybe Weds. Pix to come.

larry

[John Keeton]

Larry, I am going to go out on a limb and say that your problem is not tenon vs. recess, but more an issue of tool technique. In either event, I do hope you are able to complete the bowl. Perhaps the best teacher is experience, so you will gain from this in many ways.

[Peter Blair]

Hey Larry.
As unlikely as it may seem that John might be wrong, I just watched a very good video about tenons and recesses by Stewart Batty
http://vimeo.com/album/2603933/video/68649135
Hope I'm not out of line posting this link. If so, the video can be found by googling Stewart Batty video.

[John Keeton]

Pete, Stuart does some excellent videos and you may well be right regarding Larry's method of forming his recess or tenon. Without knowing that, and assuming he has followed the advice previously given in his thread on "Recess or tenon" and watched Stuart's video that was suggested in that thread, there is still a good chance he is encountering some catches that are launching his work.

I actually hope you are right, as that would mean a problem much easier resolved!!

[Lawrence Tarnoff]

John and Peter ...

I suspect it was a combination of a less-than-satisfactory tenon and recess and a misapplied tool. In any event, I appreciate the comments and the link. My new tenon is holding up nicely and I am en route to completing this bowl.

Larry

[Brian Kent]

John, Peter, and anyone else, what tool do you use to make the dovetail recess angle match the jaws? I have been using a spear point scraper that fits pretty well if I lay one side flat with the recess and cut in the dovetail. Same way the other direction for tenons. Is that what you do or recommend?

[Reed Gray]

Stuart's video is very well done. For cutting the dove tail, I prefer a dove tail scraper (look at my bowl turning clips on You Tube, type in robo hippy). The dove tail used in joinery like drawer sides is about 7 degrees. The specialized dove tail tool I use is pretty close to that, and to make sure, I let it hang plumb (straight up and down) from my fingers next to the chuck jaws to confirm. Easy to adjust with the grinder, especially with the CBN wheels. There are single sided and double sided dove tail tools. All you have to do is line the shaft of the tool up with the ways of the lathe, and plunge straight in. I cut just inside the line first, then just barely take the line second. You do not have to plunge in and then move sideways to get the angle, it goes sideways all by itself. The compass/divider that I use is a dedicated tool and is super glued into place so it doesn't vibrate open. I have seen another dove tail tool, but instead of being dove tailed, it has a nose kind of like this ^. Maybe less than a 90 degree angle. One tech at Craft supplies was insisting that it was easier to use than the version I use, and I just don't see it. Much easier to line up with the ways and get it perfect than to come in from the side and guess. I also do not tool in a recess for turning the bottom of a bowl. I use a forstner bit. Even though the sides of this recess are straight, the chuck jaws will give much better drive force than a spur drive. If the tail stock is engaged, the blank will not come off. Then there is no need to tool a recess, put the drive spur in the headstock, remove the drive spur, then screw on the chuck. My big Vicmark has 2 5/8 inch diameter jaws. This works great for bowls up to 14 inches or so. Over 16 inches, which I seldom do, it is getting pretty risky, so I will still use the standard jaws for turning the bottom, and then turn a bigger recess for coring and turning the inside of the bowl. To clean up my recess/finished bottom, I use a detail gouge on the angled part of the recess, and a fluteless gouge across the bottom (I show this on my fluteless gouge clip).

robo hippy