Bowl catches

[David DiOrio]

Hello all, I am new to this site, by way of background I have been turning a little over a year but have been working with wood for many years. I have made a variety of bowls some more successful than others. My thought is the more I make the better I can get, hopefully. Recently I have been having a problem on the final cut on the inside of the bowl. The outside is shaped and inside is 99% finished with even wall thickness, then on the final pass, the bowl gouge seem to want jump back and ends up splitting the wall of the bowl. The wood I am using is green with a 5/8 fingernail bowl gouge, last 3 bowls have been ruined, any suggestions would be great. Thanks everyone!

Dave

[David E Keller]

Welcome, Dave. Couple of thoughts... It's trouble going back to the rim if you've already taken the walls down to final thickness especially if they're thin. A standard grind bowl gouge is often easier for me to get the transition and the bottom. Some photos of your tool presentation would be most helpful.

[Jon McElwain]

I find that most of my catches are due to improper tool presentation. From your description, I am guessing that you are working from the rim to the center of the bowl when your catch occurs. I cut this direction as well. Make sure that when you start the cut that the flute is closed (flute is oriented like the letter C, not the letter U). Once you have cut far enough for the bevel to rub, open the flute slightly, no more than 45 degrees - a little less is better. RIDE THE BEVEL all the way to the end of the cut. Opening the flute too much and you will get a catch every time. Hope that helps, if not, please describe how you are presenting the tool to the wood and we can work from their. I went through this frustrating problem too. I learned a lot from videos and youtube. There are several turning videos out that will give you some great advice!

[Prashun Patel]

Where are you getting the jump back?

My gouge (i've also only recently found the vortex) usually skips in the middle of the inner wall, if there is an abrupt change in direction; i.e., if the walls are too steep or the bottom is too flat, and there is an abrupt change from from one to the other.

[Robert McGowen]

From your description, it sounds like you are turning green wood all the way down to it's final thickness, if it is thin enough for you to split the wall of the bowl. One possibility is that the wood is moving. The green wood is actually turning oval at the rim and as you work you way down since it is thin. When you go back anywhere near that area, you will probably turn air for a quarter revolution, then wood for a quarter revolution, then turn air for a quarter revolution, then wood for a quarter revolution. You may not even realize it, but it is there. You might not be doing anything wrong, but you might just need to change the way that you are doing them.

[Faust M. Ruggiero]

Give this a try: Roughly hollow the bowl down about 1/3 the final depth. Cut the first inch or so to the final thickness but leave a sharp shoulder where you stop. The sharp shoulder gives you a definite place and depth to begin when you continue to hollow below the first 1/3. Finish the first 1/3 to perfection including the shape of the rim. When you are done there, don't go back. Your final cut will only be the last segment of the bowl near the bottom. This is a good technique for thin walled bowls, especially "once turned" bowls.
faust

[David DiOrio]

Thanks everyone for the help I appreciate it. My tool orientation is closed (letter C) but what I am doing different is taking my cuts from the rim to the bottom with every pass, therefore it's thinning the walls evenly and also probably drying it faster making it unstable? I used to do it in thirds but didn't like the transition at the vortex, so I started to go all the way, with little luck. It does seem to be a skipping action and perhaps it's turning oval. I was turning Red Gum and was at 1/4 inch and trying to take one more pass, is it possible I was trying to get too thin? Thanks for the advice, i will try again this weekend and let you know.

[Jeff Myroup]

Thanks everyone for the help I appreciate it. My tool orientation is closed (letter C) but what I am doing different is taking my cuts from the rim to the bottom with every pass, therefore it's thinning the walls evenly and also probably drying it faster making it unstable? I used to do it in thirds but didn't like the transition at the vortex, so I started to go all the way, with little luck. It does seem to be a skipping action and perhaps it's turning oval. I was turning Red Gum and was at 1/4 inch and trying to take one more pass, is it possible I was trying to get too thin? Thanks for the advice, i will try again this weekend and let you know.

First, I would recommend you find a club to join. You will progress a lot quicker. You don't mention the size of the bowl. The bowl could have been warping on you or flexing. I would also recommend you practice on shallow bowls first before you go deeper. It will help you see what the tool is doing.

[John Beaver]

I agree that it seems like the bowl is turning oval at the rim. Also, with a 1/4" wall thickness - especially with green wood - if you use any outward pressure with your gouge it can distort the wall and have the same effect as warping, usually causing a catch.

[robert baccus]

Going through that angle transition area and on to the bottom is tough. there is an easy solution i stumbeled on 20 years ago. it seems to be a secret among turners though. simply buy a cheap 1/2" "U" flute bowl gouge and grind it almost flat. something like a 75 deg. angle. you will find the bevel rides nicely on the bowl bottom and the tool is completely behaved. it even does a great finish cut on bowlbottoms and platter faces.-----foolproof-----------old forester

[David DiOrio]

thanks everyone!