Torsion box

[John Branam]

I think it is time that i have a truely flat surface for glue ups and assembly so I am going to build a torsion box. My shop is in my basement and like most people I have limited space, so I am looking to make a box that can be place on top of saw horses while in use and then stored away when not in use. Has anyone built anything simular to this? I am also looking for input on materials to use for the construction of this torsion box. Anyhelp is appreciated.

[Keith Starosta]

Hi John. This is a topic that's been talked about quite a bit before. Check out this thread started by our own SketchUp king, Todd Burch. He provides some really good information about torsion boxes and their ueses...

http://www.sawmillcreek.org/showthread.php?t=6088&highlight=torsion

Hope this helps!

Keith

[Bartee Lamar]

David Marks did a show on this.

David Marks Web site with picture (http://www.djmarks.com/woodworks/409.asp) (click on the pictures for a larger picture)

I think he used all 1/2" MDF with lots of glue and nail gun action.

Then he wrapped it in mahogany ( I think ).

I think the interior strips were about 3" The interior stips were not cross joined. He used long strips and cut small blocks which were nailed and glued between the long stips to form the lattice interior structure.

Maybe some other's will remember more about the show. David does not have any plans posted for this project.

I have comtemplated this for my basement workshop and I think I would hang this from the ceiling and lower when I needed it.

[Jamie Buxton]

Here's notes to a talk I did about torsion boxes for my woodworking club several years ago. http://www.geocities.com/bawanewsletter/jun02/torsionbox1.pdf Eighth-inch plywood works just fine for the spacer grid. You can gang-cut the slots with a standard-kerf blade.
The only change I've evolved since then is that when I'm gang-cutting the spacer strips, I no longer clamp them together; clamps near the table saw scared me. Instead, I now bundle them together with that Saran-Wrap-like packing material, and cut right through it.

[Greg Ladd]

John,

As mentioned earlier, wood works did an episode on torsion boxes awhile back. It is explained very clearly on the DIY website (DIYnetwrk.com). The pictures explain it very well.

Here is a link. http://diynetwork.com/diy/shows_wwk/episode/0,2046,DIY_14350_26946,00.html It is episode WWk 409 in case the link doesn't work.

Greg

[John Branam]

Great info everyone! Thanks for the help.

[Michael Ballent]

I watched that episode, and it was excellent... Too bad that they do not sell the videos for his shows... I think that they would sell pretty well.


John,

As mentioned earlier, wood works did an episode on torsion boxes awhile back. It is explained very clearly on the DIY website (DIYnetwrk.com). The pictures explain it very well.

Here is a link. http://diynetwork.com/diy/shows_wwk/episode/0,2046,DIY_14350_26946,00.html It is episode WWk 409 in case the link doesn't work.

Greg

[Chris Padilla]

Mike, I agree. If the put Woodworks or any of The New Yankee on DVDs (like 5-10 shows per), I think they would sell quite well. Heck, if Netflix carried them, I'd rent them!

[Chris Padilla]

The most important thing to remember about a torsion box is that it will only be as flat as the surface you build it upon. I think MDF is a great material for a cheap, yet flat (and heavy!) torsion box. MDF is dimensionally stable and its thickness tolerance is very, very tight so 3/4" is pretty dead-on.

[Roger Everett]

John:
I built one 13 years ago for the same purpose as you're looking to use for. Mine is 44X95 W/ 1/4" birch ply on one side and 1/2" birch on other, the frame and grid I made out of 3/4x1 3/4" poplar, which I ran over the joiner and then thru the planner , then glued up on a true flat workbench I had built. The poplar and thickness of the ply keeps the weight down, as I just lean it against the wall behind my roll around ply rack, and yes it comes in very handy when needed. When I built it, I was in part testing the idea for another project that would need to have a torsion box base built for it, so I put it on 2 sawhorses and had 2 guys next door set on it to check for deflection. About a pinch over 1/16" at center, and thats with 2 healthy well feed guys with a beer in hand setting in middle.
Roger

[Michael Perata]

The torsion box can get quite heavy if overbuilt and then difficult to put away.

I bought a 4'0" X 8'0" hollow core interior grade door from a big box and then glued a sheet of 1/2" MDF top and bottom. The door weighed about 25# so the entire assembly was relatively light, and very, very strong.

[Chris Padilla]

Mike has a good point. My torsion box made out of all 3/4" MDF is pretty heavy but it forms the base of my workbench so no biggie.

As in everything, it all depends on what you want to do with it.