What is a torsion box?

[Silas Smith]

I know this question shows my newbieness, but could someone walk me through what one is, how to build it and what the benefits are?

[Jim O'Dell]

Silas,
There have been some good discusions here at the Creek about torsion boxes. Do a search on it and you will come up with a wealth of information, much better than I could relay here. But think of a hollow core door, or even more visable, a piece of cardboard. Thin skin on both sides of a webbed structure. Using plywood or MDF for the cross pattern inside, not wavy like cardboard. It becomes much stronger than the individual components, and if built of a flat surface, stays flat. Great for benches. Jim.

[Chris DeHut]

Jim's got it right, but keep in mind that if you make it out of a wood product, it has the chance of warping. I have had two of them warp in the shop, both made entirely out of Birch plywood. It should be noted too that in both cases, the torsion boxes were subjected to wide swings in moisture.

They are great structures with a lot of applications in woodworking.

Chris

[Dan Stuewe]

Just to bring it up since I haven't heard it mentioned for a while (and it was a great bit of info when I first heard about it). If you scroll down all the way to the bottom of this thread, you'll find links to similar threads (all threads have this feature). In this example there is a link to a great piece written by Todd Burch that should answer your questions (of course Jim did a great job of answering it already).

[Silas Smith]

Thanks for the lead guys, I'm going to try and build one for my table saw extention.

[Jim O'Dell]

Just proves you can learn something every day!! I didn't know about the similar threads box at the bottom. TOO COOL!! Jim.

[Keith Christopher]

I use my torsion box assemble. It's level and flat and that way I can better determine the look of my project. I saw a DMarks episode where he talked about torsion boxes and I thought what a grand idea. But then again it's no secret I'm a DMarks fan.

[Louis Haremski]

I'm planning on making a set of torsion box shelves for an entertainment center and bookcase. Are there an rules or formulas to calculate the relationships between the thickness of the shelves and their projection from the wall to determine how much weight they will hold? Since I'm expecting a new plasma TV, I don't need to support several hundred pounds off one ledger. Maximum projection for components won't be more that 14". But there will be shelves for books and pottery.
I've read through the prior postings on this site and have seen the old Fine Woodworking article by Ian Kirby. Any help?

[Chris Padilla]

Folks,

Scroll to the very bottom of this thread and look at the "Similar Threads" window/box. You'll find good stuff there.