Flat Portable work bench top?

[Andrew Wayland]

I posted earlier this year about MFT alternatives, and received a lot of good feedback.

Since then I’ve been back to the drawing board and I’ve been researching options/evaluating my needs.

The Paulk bench really seems like the perfect blend of functionality and price: but storage is a concern for me: I’m not sure where I would be able to store a couple of 10-12” deep boxes in my garage.

But, it’s my understanding that you need the torsion box to maintain a flat work surface with plywood.

Would MDF maintain the flatness over time? Or would that too need a frame?

[Dave Seng]

MDF would definitely need a framework to support itself. And it would be a lot heavier than the same size and thickness plywood.

[Paul F Franklin]

MDF usually stays flat if it's stored flat, but it's not rigid enough to be a work surface without a supporting structure under it.

FWIW, a torsion box doesn't need to be 10-12 inches thick to be sturdy and stay flat. Many folks build them 3-4 thick and they do fine.

I happened to be at Hartville Hardware a week or two ago. They had a big display of the Bora Centipede and their new top for it. I was impressed enough with the quality of the top that I bought one (I already have a centipede or two). Frankly, if you need portable and easy to store and can live with 2' x 4' (or a multiple) it would be hard to beat for the price.

[Jim Becker]

A torsion box doesn't have to be 10-12" thick to be stable. If you want something portable, go thinner...you'l just be giving up the convenient cubbies, but have the same benefits, especially for a smaller, more manageably portable bench size.

[Andrew Wayland]

MDF usually stays flat if it's stored flat, but it's not rigid enough to be a work surface without a supporting structure under it.

FWIW, a torsion box doesn't need to be 10-12 inches thick to be sturdy and stay flat. Many folks build them 3-4 thick and they do fine.

I happened to be at Hartville Hardware a week or two ago. They had a big display of the Bora Centipede and their new top for it. I was impressed enough with the quality of the top that I bought one (I already have a centipede or two). Frankly, if you need portable and easy to store and can live with 2' x 4' (or a multiple) it would be hard to beat for the price.

I should have added: I would be using a centipede or a couple of Kreg worktables as the base.

The centipede top is one that I brought up before. There was a question about how the center hinge would lay flat if the ground beneath the centipede wasn’t perfect: I was thinking of using a parf guide to build a top to sit on the centipede: thereby bypassing the need for a torsion setup?

[Jim Becker]

I use my Centipedes with some portable surfaces that are sorta-torsion-boxes-but-not-built-as-well-as-they-could-be. A nice surface on them would work fine although they do wiggle a bit...but you likely know that already.

[Andrew Wayland]

I use my Centipedes with some portable surfaces that are sorta-torsion-boxes-but-not-built-as-well-as-they-could-be. A nice surface on them would work fine although they do wiggle a bit...but you likely know that already.

Jim: can you expand on what your surfaces are?

I have two 2x4 centipedes currently: I was thinking I could fab up a 4x6 or 4x7 MDF top for them. My thought was the MDF would be decently supported by the two centipedes.... and the 6-7’ length would be a bit of a weight savings making the top easier to handle than a full 4x8.

My mistake was going with 36” high centipedes: so using a 2x4 for added strength is only raising my height to uncomfortable levels.

[Jim Becker]

The existing, quickly made surfaces are just skins of .5" plywood with scrap solid wood to make up the internals. For your idea, you don't need to use the same thickness MDF for the bottom skin or even to use MDF so you can save weight if you prefer. The Centipedes can handle a LOT of weight top to bottom. For thickness, if you are just using typical dogs on the worksurface, you only need clearance for a an inch or two below the top surface. I would say that you could likely be fine with, say...2" thick internal grids with the the .75" MDF top and a .5" quality plywood bottom. If you do want more mass, use the .75" MDF for the bottom, too. Sand any MDF surfaces that will be glued to insure good adhesion. Use solid stock or decent plywood for the internal grid for stiffness and good glue/screw characteristics.

[Andrew Wayland]

I’m thinking MDF in such a fashion would certainly be too heavy for maneuvering.

I’m curious how stable Baltic birch is by comparison?

[Jim Becker]

BB is very good for stability (the real stuff) and if you build the torsion box on a known flat surface, such as your table saw, once the glue fully cures, it's going to stay pretty darn flat. One thing to consider is to build the whole torsion box out of, say, half-inch (12mm) BB plywood and have a replaceable MDF grid top bolted to that. If you put open grooves in the top surface of the BB that match the grid pattern, you'll still have the strength without affecting use of the dog holes on the work surface.

[johnny means]

My favorite portable surface is the lowly Masonite hollow core door. They weigh nothing, yet, are flat and stiff and stay that way. Laminated they make an excellent glue up surface. Of course, any dog holes have a finite lifespan. But they're cheap enough for me to toss them when they get too beat up.

[Andrew Wayland]

Ah: that hadn’t crossed my mind. Might do that the next go-around.

For now, I ended up grabbing a sheet of lightweight MDF. We’ll see how long it lasts....

Worked nicely for my weekend projects though!

[Tom Trees]

Here is some food for thought, not mine but grabbed from the biggest collection of benches on the net, by a longshot,, from a thread called....
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