Knowledge You Can Build On — Est. 1998
What did I do wrong?
Carole in VA
>After watching Bill's video about 4 times, I finally got up the nerve to try a bowl out of a chunk of paulownia. Turned the outside and turned a tenon to fit my Nova Midi and chucked the bowl and started on the inside. I got a very small catch and the tenon separated from the bowl at the shoulder. What did I do wrong? Does this happen often? The paulownia is very soft and "pithy"...tools that cut other woods smooth as silk still leave this stuff fuzzy as heck.
Re: What did I do wrong?
John Lucas
>Carol
can't say for sure because I haven't seen a photo of you bowl. I have turned a lot of that wood and it's fairly strong in the long grain direction but kinda weak in the short grain. I'm guessing your tenon was somewhat small and sheared off parallel to the grain. I've turned lots of mirrors and ornaments with the stuff but never used it to turn ornament finials or bowls.
Re: What did I do wrong?
MikeinCapeMay
>How long was the tenon? It should not be so long as to bottom out in the chuck. The chuck jaws should rest on a squared up shouder next to the tenon. In other words the tenon should not be so long/deep as to have tenon protruding from the jaws with the bowl itself sitting up away from the chuck jaws. I hope I made myself clear.
Re: What did I do wrong?
Barbara Gill, Remlik VA
>I have never had a tenon fail. You are starting with a wood that can be difficult. It tends to tear out. The good side is that it sands well.
Not a beginner's wood
TD
>Carole, pawlonia requires a very sharp tool and perfect technique. While learning I would suggest poplar or soft maple. Was the catch on the inside or outside of the bowl?
TD
Re: What did I do wrong?
Carole in VA
>Here's a pic. The tenon was 2" in diam. And don't laugh at the shape...I consider myself lucky to get semi-round at this stage! LOL
Re: What did I do wrong?
Carole in VA
>The tenon was about 1/4" deep and did not bottom out. I had the shoulder tight against the top of the jaws. This wood just seems a little punky.
Re: What did I do wrong?
rprevett
>Carole, I've seen these many times in my shop :-). What I've done is to run a bead of CA around the tenon right at the base. This hardens up that section and has decreased my sheared tenon accidents.
Re: What did I do wrong?
Ruth in S.Cal
>This happened to me more than once...then i turned the tennon a tad longer and also at an angle, can't remeber the direction, but when I looked at the chuck there seemed to be a raised edge on the part that grips the tennon....and I figured I didn't have enough surface gripping....so I turned it so that I would have grip beneath the bit that stuck out.........that's my very technical description!! :)
Re: What did I do wrong?
Jim Pugh, Ohio
>Carole, it is just possible you didn't do anything wrong. Sometimes the wood is weak and sometimes..... Anyway, you can probably salvage the bowl. Use your chuck as a jam chuck, place the open side of the bowl against it, bring up the tail center and put it as near the actual center as you can. Re-cut the tenon. 1/4" long seems adequate for the size of the bowl. Try not to make the junction of the tenon at the bowl smaller than the tenon itself..in otherwords, don't taper the tenon smaller unless you are using a chuck that requires it. Anyway, you haven't lost much, try it again.
Re: What did I do wrong?
Wally Dickerman at Green Valley, Az.
>True up the bottom and put on a glue block. Works really well for soft punky woods. Cut a tenon on the glue block for your chuck, or better yet, use a faceplate.
Wally
Re: What did I do wrong?
Bruce McElhaney Spring Lake, MI
>It's happened to me a couple of times. Even if you do everything right, some woods can break a tennon with a catch, but usually it's a big catch.
Never turned Paulownia, in fact never even heard of it. What kind of wood is it?
Re: What did I do wrong?
Carole in VA
>I think you are talking about the dovetail? If so, yes, the Nova chucks take a dovetail tenon. I took great pains to match that when I turned my tenon, but maybe I did it wrong.
Re: What did I do wrong?
Carole in VA
>Thanks, Wally! I have not given up on it yet. The good news is I had the lathe set at it's lowest speed, so the thing didn't fly around the shop...just sort of fell off. ;-)
Re: What did I do wrong?
Joseph
>Try to get some slow grown Paulownia. The plantation wood is poop.
There was a thread about Paulownia about a week ago. I make turkey calls and after reading that thread, decided to see what I could do with a few logs I have laying around. All the logs had anywhere from 5-12 rings per inch (from a tree that was grown under a dense canopy of mature oaks). It turned like butter. It took a while to get all the fur balls off it, but it was worth the extra effort.
Re: What did I do wrong?
Carole in VA
>This is definitely plantation grown. Very, very wide spacing between growth rings...an inch or more in places. I have decided it is really not good for much of anything...too darn soft, but I decided to play with it anyway. I re-turned the tenon on the bowl, saturated it with CA and let it dry. Chucked it up and pulled up the tailstock for support. Got about an inch into the inside of the bowl and had a catch...the wood severed from the bottom of the bowl, well away from the chuck. Through this process, I at least had the fun of turning the outside of a bowl for the first time (I got it much better on the second go round) and gained some experience with shear cutting, etc. Not the least bit discouraged, but rather excited to find another blank of a decent wood and have at it! :-)
