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tenons

2K views 30 replies 10 participants last post by  Karda 
#1 · (Edited by Moderator)
If it were not for tenons I would have fun woodturning. If i ruin a turning it is usually removing the tenon. When I turn towards the center I get a lot of noise and vibration and I never am able to flaten the center I always have a high spot. That where I ruin the bowl
 
#4 ·
I have Jerrys steady, this is not a holding issue this is the tool. I have the same problems with the steady. I didn't have the vibration issue until recently, I have always had a high center problem. I may go back to a recess except I can't use them on first turned bowlsa
 
#5 ·
When you say you "ruin the bowl" do you mean because it won't sit flat when you're done? If that's the case, it may be the way you are creating the tenon in the first place. I like to create the base (which is not the bottom) of the bowl with the tenon surrounded by a recessed area. When I remove the tenon, I only need to remove enough of it to make sure it is lower than the base. If you need a link to a video, let me know.
 
#6 ·
Hi, Phill I know how you do your tenons, I watch your videos, a lot. I am going to try your method of tenons buy I always forget. Right now I am more worried about the vibration and the noise, I can't figure it out and it is new. What am I doing wrong. I had the opportunity to show a very experienced turn what is happening but i forgot to ask. Now it back to dumb old me
 
#7 ·
Maybe it might be that the tailstock is cranked in too hard. It puts everything under high stress, and that might cause a vibration against the friction fit against your inside-the-bowl piece - IF that is how you do the final tenon removal. It has happened to me. Maybe back off the tiniest bit, or change the pad inside to something more compliant, even a sheet of silicone rubber…

On a completely different note, I often turn the bowl mounted to a face plate the whole time when there is enough wood or when I can glue on a sacrificial block. Then I turn inside and out without ever remounting. After sanding, I use a parting tool to cut away the bowl with a little angle inward so that there is a recess. I part down to about 1/2" if the wood is good, saw it off, then just clean it up with a gouge.

Hope this helps, sorry if it doesn't
 
#14 ·
Hi, Phill I know how you do your tenons, I watch your videos, a lot. I am going to try your method of tenons buy I always forget. Right now I am more worried about the vibration and the noise, I can t figure it out and it is new. What am I doing wrong. I had the opportunity to show a very experienced turn what is happening but i forgot to ask. Now it back to dumb old me

- Karda
It may be your tool rest height. I experience a little of what you are talking about if I don't have my tool rest high enough. Then it's chisel angle may be the culprit. Go slow, there's no rush. It'll come!
 
#16 ·
You may be running too low rpm. I use jam chucks - various sizes - that fit the bowl ID. I make sure the tenon has the original live center spot from when the tenon was formed. A thin 1/16" piece of leather is the best cushion. I just put the point of the live center into the original center hole, and tighten until there is sufficient friction to keep the bowl turning. Depending on bowl size I run 750-1000 rpm for tenon removal, using light cuts. No tail steady or other special tools required. Some of the bowls are only 1/8" wall.
 
#18 ·
thats what I do but no leather

- Karda
What tool are you using? I usually use a 5/8" bowl gouge to get the majority of material, then a 1/2" spindle gouge to slick it up and remove most of the button under the TS point. Have you tried a freshly sharpened tool? Tool rest set to be able to drop the tool handle a bit and have the cutting edge at center.
 
#19 ·
Sometimes a donut chuck IS the simplest way. You can get the tailstock completely out of the way and the risk of it coming off is zero. It is also easy to make. Cole jaws or Longworth chuck are also handy to have as well.
 
#20 ·
I use a 5/8 1/2" bowl gouge ground to 55 degrees. I can usually get good cuts moving forward it is the back cutting or scraping to remove the high spot near the tenon that I have trouble mean while the noise goes on. very distracting. I am turning a large box. when I parted it of the did a pull cut the a scrape from the center to lip it still made noise
 
#22 · (Edited by Moderator)
Sounds like you are using the wing for a horizontal scraping cut. Not surprised you get vibration. Drop the handle so the edge cuts at an angle. Drop the tool rest as needed, cut should be just above center.

Assume you are using an Ellsworth type grind with ~3/4" inch wings? Drop the tool rest and then drop the handle down. Ideally the handle will be 45 deg to the tool rest, and the edge ~45 deg to the cut, right wing making contact and the left wing ~1/16" from the wood. This is the classic shear scrape. The angles can be less, but hopefully you get the idea. I also use a bevel touching slicing pull cut, used by Ellsworth. Cut is on the left bevel, drop the tool handle, flute straight up, tool touching wood, rotate handle to the left, ccw, until the bevel and then the edge contacts wood. Cut occurs about 1/3 way back from the nose. I use it to refine the OD after roughing and to remove a tenon.
 
#25 ·
i have watched the videos its a matter of doing exactly whats in the video. I am missing something and wasting a lot of metal. example: why is the tip of my tool pointed and why can't I get the point out. I had an old gouge ground for a bottom tool, I reground it for 40/40. The tip was broad and it cut good. but as I sharpened it it developed a point and I couldn't get the point out
 
#26 · (Edited by Moderator)
I have found using a worm screw will do the job on even my biggest pieces to work down. If I was fearful of that, I'd just use a faceplate. I've seen guys be very successful with a jam chuck. But I know the worm screw is going to hold for my bowls. The tailstock is usually used for the roughing… just not in these pictures.

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