Why so little triangulation for strength under a workbench?

[Owen Lawrence]

Everybody goes to great lengths to make their woodworking benches heavy and strong for stability. But one thing I've always wondered is why there are no obvious angled supports between the legs and stretchers. The only triangulation would come from within the widths and thicknesses of the legs and stretchers.

When I built my drillpress stand, out of 2x4s and 2x6s, I put in additional boards on the sides going from the front bottom to the back top. It was very strong front to back, but wobbled a very little bit side-to-side. I put an additional angled piece on the back (couldn't do the front because of the drawer and retractable wheel mechanism) and now it behaves as if the whole thing is made of one block of steel. Super strong! Cabinets work this way, too, by having the triangles inside the sheet goods used to surface the frame (if there is one).

So how come nobody adds angled supports to the base, say with angled mortises and tenons? Lee Valley's bench has this elabourite system of steel truss rods. I wouldn't think those would be needed at all if there were a few well placed wooden pieces added to the design. All chance of racking would be completely eliminated.

When I build another bench I plan to add these pieces to the design, but since I've never seen it like this before I seriously wonder if I should. You thoughts please?

Thanks.

- Owen -

[Bruce T]

I've often wondered the same thing and, like you, have added angled braces in many structures. The only thing that I've changed over the years is to fortify my attachment points (more screws. bolts, or whatever than normal). Other than that, they work extremely well.

BruceT

[David Merrill]

As a retired structural analyst, I've noticed the same lack of wracking resistance. It would seem especially important if the bench is to be used for tasks such as hand planing where the forces are applied parallel to the top surface and not important if the bench is being used primarily for tasks where the forces are oriented vertically.

I would also suggest, as an alternative to angled members, the use of plywood shear panels on the back, sides (and front if no drawers or shelves are planned). The panels, when rigidly attached to the legs, would provide wracking resistance in the same manner as does plywood sheathing on house framing. Many other workshop tables, tool bases and stands could benefit from the same treatment, e.g. router tables; many of the designs I see in woodworking magazines, and commercial offerings as well, appear to completely ignore wracking resistance. Shear panels can easily be retrofit to existing benches and stands that lack them, greatly increasing their rigidity.

David Merrill

[Lew Hodgett]

See my comment about 1/2" CDX gussets in "wood for work bench" post.

Lew

[Steve DeMars]

I believe the reason you do not see triangles on the back of well built benches is the same reason you don't see a large 2" pipe bumper surrounding a new Jaguar. After all, this would prevent dings, which we all know Jag owners fear more than death it self.

It's looks, looks, appearance, style, staying with the old look, etc . . .

[Duane Bozarth]

And w/ most old, original benches, well crafted, significant sized mortise/tenon joints that eliminate the need...

[jo4hn]

My bench was built from 4x4 legs and 2x4 everything else. I used M&T joinery throughout. The top is bolted to the undercarriage with 3/8" bolts (just happened to have a supply). No angled supports at all. After 8 years, still no movement of any kind. mahalo, jo4hn

[CW]

You say "staying with the old look". Why didn't people centuries ago incorperate those things? They knew of the advantages then.

surrounding

[Ellestad]

I think that the massive approach builds a bench that is strong, steady, and . . . dead! The cross-braced approach tends to build a bench that is lighter, strong, steady, and . . . resonant! I like a bench that doesn't vibrate so that when something bumps everything on the bench doesn't dance around. A real monolith would be ideal.

Tim Ellestad

[Guess who]

Because they are heavy enough and strong enough already. Mine's solid maple, 9' by about 2' 6", 12 drawers, plus two upper wide thinner drawers, handed to me when I was moving one time. In fact, I'd made myself a couple of lighter models, and when this was offered, threw them out to take this one in the moving van. What more do you need if you have what you need?

[Guess who]

I must be weaker than you? My planes are sharp enough to not meet so much resistance and are used with a smooth application; certainly not even remotely close to the forces needed to pull my solid, well-built workbench apart. If your planes are dull and you try to gouge off half-inch thick shavings you might have a point.

[CW]

Are you really an asshole or do you just play one on the internet?

[Guess who]

No, but you surely are. I was being serious, and my reply was not to you in any case, so mind your own damned business. He seemed to think that it was necessary to state being a structural analyst, as if that made a difference. That was not at all necessary, since the forces are in fact so relatively small, so what in hell does force of planing have to do with the strength of a well-made workbench, and why do you need to be some sort of expert to explain it? I have a degree in math and physics, and that makes no difference either. Anyhow, I need not explain myself to someone so obviously too stupid to understand. Stick to your woodworking, if in fact you do any. I'm done here.

[WillR]

I added those shear panels to one bench I made -- they actually formed a =

"drawer box -- complete with drawers :-) " -- and they certainly do=20 increase the rigidity of the table. I also added them to the saw=20 out-feed table -- it allowed me to use light materials and have a rigid=20 table.

It makes a big difference if the bench is built with "light" materials=20

-- 2X4's and MDF as was my original work bench. The panels do increase=20 the "stiffness" greatly. Not so sure it would do much for a properly=20 made work bench -- which my first one wasn't.

--=20 Will R. Jewel Boxes and Wood Art

power of accurate observation is commonly called cynicism by those=20 who have not got it.=94 George Bernard Shaw

[CW]

Yep, you really are an asshole. Thanks for the confirmation.

[Guess who]

You are merely confirming your own character. Now, I'm not here for your rubbish; you're kill-filed.

[CW]

Now, I'm not here for

[Prometheus]

Yep. As a poor boy, most of my benches are made from framing stock, and the racking resistance comes from using a 1.5" x 3" through tenons mounted through the legs (doubled up two by fours) that are bolted into place with big lag screws. Solid enough for just about anything- a M&T joint that size doesn't submit to racking forces very easily.

That being said, I've got some older ones that do have cross-bracing because I just screwed some single two by fours to the corners of the tops, and the things wobbled like crazy until they were braced. It all just depends on how you've built it in the first place, and whether or not you like the look of the bracing in the back- everything has it's place.

[John D'Errico]

Those diagonal braces interfere with the nice cabinetry that you build under the bench. Its storage space, in the most convenient place. Mortise and tenon construction makes it stiff. I used that, plus the Lee Valley threaded rods under tension to keep it stiff for my lifetime.

John

[Obfuscated]

Here's the reason ... the full reason: the braces and sheer panels aren't used because they aren't needed. The massive construction typically used provides inertial resistance to sudden loads and the rigid joinery privides resistance against sustained loads.

If you build a light weight workbench you may need braces. If you build a bench with so much wood that it leaves a gap in the forest visible from space, bracing is probably wasted effort.

Since the wood is subject to a lot of different stresses, such as being used as a vise from various angles and having lots of things whacked on it, I opt for a workbench so heavy it leaves marks in my concrete floor.

Bill