# Plywood for Torsion Box



## Dchip (Jun 30, 2009)

Given the size of my shop, I would like to build an all-in-one workbench/assembly table. Since this will include a vise, I'm favoring plywood for the box construction due to its greater holding power of screws and bolts and such, with a 3/4'' MDF and hardboard top. Will I face any problems using a combination of MDF and plywood? Would using plywood as the grid material jeopardize "absolute flatness", and is even plywood prone to subtle movement due to its grain structure? All input is appreciated. Thanks.


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## a1Jim (Aug 9, 2008)

Hey Dan
MDF is much flatter and more stable and can be backed up with solid wood for mounting a vise.


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## a1Jim (Aug 9, 2008)

I've seen David Marks build and now Marc make torsion box table tops. I really don't see the point other than saying I have a torsion box table. This is not meant as a criticism to Prairiefire. David Marks or Mark.


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## Rick Dennington (Aug 27, 2009)

Greetings Dchip: I agree with what Jim said about a torsion box table…. you really don't need one if you build a good solid top for it. I've got 5 workbenches in my shop, and 2 have MDF tops on them. My main w.b. is a Douglas Fir frame w/ a 3" layered MDF top glued and screwed together. It is dead-flat, and I have 2 vices mounted to it with lag bolts, and them puppies ain't going nowhere. Good layers of a good finish, and you're good to go…... forget the torsion box…. it's just braggin' rights…....


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## Dchip (Jun 30, 2009)

Thanks for all the input. I'm not exactly gung-ho on the idea of building the torsion-box, but I am adamant about long-term flatness. My main concern is that this top will be fixed to an old dresser as the base (until I get time and money to build a proper base) and pushed up against the wall. This will leave about an 8'' overhang that will eventually hold a vise, and it just seems to me that the internal vertical slats of the torsion box would support this otherwise unsupported weight better than laminated sheets of plywood or MDF. Solid wood is still an option, though lack of a power jointer and planer makes this option less appealing


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## Sawkerf (Dec 31, 2009)

I've built a few torsion boxes. but only four of them really needed to be torsion boxes. They're neat, but you really gotta have a good reason to justify the effort required to make them.

My work bench also serves as the outfeed table for my TS. It's made with 4" x 4" legs, 2" x 6" framing, and a piece of 3/4" ACX for the top. It's still stout, stable, and flat after eight years of pretty hard use.

I've had a couple of issues with furniture wobbling, but those were due to uneven floors (tile or hardwood) and not my workbench.

Dan, if I were you, I would forget using an old dresser base as a workbench cabinet. I doubt if it's anywhere near strong enough to survive the thumping and bumping it will get.


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