Inside-Out Turning problem

[Royce Meritt]

I am trying to teach myself the technique of "inside-out" turning. In a nut shell, for those of you who might not be familiar with this techinque, you start by temporarily assembling 4 pieces of stock, turn your inside shape, re-assemble the 4 pieces at 180 degrees. What you just turned now becomes the inside of the hollow form. Then you turn the outside shape.

At any rate, I am having a problem. Because the flat surfaces must be quite perfect for the re-assembly, the transition between the flat surfaces and the start of the curved surface has to be as perfect as one can get them.

I am getting some unacceptable tear-out at the start of the curved portion. (Is any of this making ANY SENSE?) Aside from using VERY sharp tools, can anyone think of something I can do in terms of technique that will give me better results?

The crude sketch I've attached might help. Thanks.

[robert hainstock]

How did you get the wood to this point? Not knowing the size of the pieces or the Recess Dia. Hard to tell what you are trying to do. Try clamping the two pieces together and turning the recess through them, that usualy works to reduce tearout in flatwork.:confused:
Bob

[Rich Stewart]

Probably have to use a skew. I think that'll be the only way to get rid of the tear-out. Good luck.

[Gordon Seto]

It is basically a pommel cut.
Sharp tool, light cuts, speed up your lathe within your safety zone. From the drawing, you are doing a cove, a skew won't work. Aim your tool bevel towards the direction you are going, from large towards the center and no scraping.
Try the technique on some solid square first. If you still have problem, post a picture of your gouge tip. May be your angle is too blunt.

[Mike Golka]

If, like me you only had the tearout problem right at the corners then as suggested before a skew to slightly score the edge of the cut works very well.

Mike

[Jim King]

Maybe these photos will help

[Royce Meritt]

Thanks for all the suggestions.

Gordon: Your suggestion about the gouge angle may be right. I'll try again with a different gouge.

Mike: I'll also try a light scoring with a skew.

Jim: I like that inside-out hollow form you posted.

Thanks again everyone.

[Bill Wyko]

What I have done to prevent this is to make a saw cut before you turn the piece. Then turn inside the saw cut. Good luck.

[Gordon Seto]

Royce,

Your tear out is on the exit faces of each corner. Because there are no fiber supporting the cut. Change your attack angle of your gouge, aiming towards the center, rather than upwards (tangent to the cylinder). If your gouge is cutting towards the center, even the corners fibers have support behind them. You will have a cleaner cut shearing each strand of the wood rather than breaking them. You rotate your gouge counter-clockwise to open up the cut after you have started the cut.

[Royce Meritt]

Thanks for the tips everyone. I tried several of your suggestions last night with much better results. Now I need to work on refining the shapes I am trying for. I'll keep you posted. Thanks again.

[Larry Marley]

It is basically a pommel cut.
Sharp tool, light cuts, speed up your lathe within your safety zone. From the drawing, you are doing a cove, a skew won't work. Aim your tool bevel towards the direction you are going, from large towards the center and no scraping.
Try the technique on some solid square first. If you still have problem, post a picture of your gouge tip. May be your angle is too blunt.


Yep, what Gordon said. I have turned several of these and just used a spindle gouge. sharp, light, and a little speed helps.

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