Hollow Form Failures

[Joe Bradshaw]

More of my hollow form failures


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[Steve Schlumpf]

Failures? I see design opportunities! Especially the second from the left!

[Wally Dickerman]

Woodturning is a learning experience....Question is, do you know why these bowl busting things happened?

As Steve says....Consider at least a couple of them to be "Design change opportunities".....get 'em back on the lathe.

I like the saying....Make your mistakes look like that's what you intended to do in the first place.

[John Keeton]

Joe, you could take the second one (really nice form) and create a flowing cut into the side all the way to the bottom and create a very contemporary piece of art. A fellow at our club turned a similar form and made an "S" shaped cut, painted the interior and edges of the cut black, and it was a very dramatic piece.

[Jim Burr]

Ouch Joe! Maybe a little thicker and your vision will stay intact. Lot's of opportunity for saves in those pictures. All of 'em look like great pieces.

[Chip Sutherland]

All of them are savable. I'm still fixing things from years ago. And keep your makes a secret. For some reason I want to tell every woodturner about the mistakes in each piece but I learned to stop telling potential buyers and gift recipients.

By chance were you touching up the rim when these failed? :confused: I only ask because I have a couple of mistakes that look suspiciously like yours and I can trace it back to touching up the rim or side wall too close to the top. I've learned now not to do that and instead use sand paper to achieve whatever I'm obsessing over.

Looks like that wormy piece of mesquite(?) in the 3rd piece probably had some structural weakness. On any piece that is really wormy or has voids, inclusions, cracks, I either use painters tape or shrink wrap to wrap the outside to mitigate the flex than will occur when hollowing. My wall thickness gauge isn't as accurate but luckily I'm not from the school of thin wall-ism...unless I intend to pierce it. This is also a safety measure in case the piece explodes, too.

Even a bowl steady might have helped. I've set mine up plenty of times when it probably didn't have to.

[Nate Davey]

I have a failure similar to the 2nd and 3rd pics. Wasn't paying attention on exit and slammed the shaft into the rim.

[Michael James]

Wasn't paying attention on exit and slammed the shaft into the rim.

I really hate when that happens! :eek:

Silently mumbling to myself....ok turn it off, put down the sharp object and walk away....walk away now and do not look back!

[Bill Boehme]

Joe,

At the very least, they are learning opportunities and in many cases they will also be design opportunities. Here are the two cardinal rules of hollow forms:


The inside diameter absolutely positively must be less than the outside diameter.
Never go back.

Everything else is negotiable.

It look like you came petty close to breaking rule #1. That would have been OK, but as you know you violated rule #2 by touching the rim. I would be lying if I said that I never did that also. I think that it would be a good idea to stop the lathe before retracting the tool.

[Bob Bergstrom]

Boy, you've got the outside down perfectly. Now let's talk about Steve idea of design opportunities. Time to get out the coping saw and carving tools.

[Bernie Weishapl]

I agree with the design opportunity for sure. I could see couple things that could be done.