Torsion Box Portable Workbench

[Bolster]

Torsion Box Portable Workbench

Lots of you have wonderful, stationary shops, and I envy you. A fair amount of my work is at remote locations, and I have to shlep seemingly uncountable toolboxes to the worksite to get the job done.

One thing I really miss at these remote sessions is a sturdy workbench, with a vise. At any particular location you’re likely to see me bent over on the earth like an inchworm, trying to hold down a piece of metal or wood with my feet and knees while I cut or grind it to size. Ow, my back. Unacceptable!

When I’m lucky, I can throw a discarded door or piece of plywood across two sawhorses for a makeshift bench. Also unacceptable.

I recently read and article in Fine Woodworking, about a guy who swears by his shop-built torsion-box bench…which he uses for his main shop bench! (I uploaded the article here so you can see it.) I fell in love with the idea, but wanted to make it lighter (= more portable; all those 2x4s would heavy it up real fast) and not have that tangle of 8 legs under it (which would all need shimming to get it level).

So my goal is to make a STURDY, LIGHTWEIGHT, PORTABLE bench that breaks down for travel, that’s roughly 2’ x 8’ in size. I’m shooting for a load capacity of 300 lbs. (What good is it if you can’t take a nap on it? Huh huh huh.)

I asked my clever BIL, a commercial architect, to design it (see his drawings here and here). He came up with the idea of metal studs. So that’s where I’m headed. Succeed or fail, I’ll post updates here as I make my way along.

Materials to date:
5x 8ft G-section steel 3.5" beams, 2x 10ft C-section 3.5" beams…$28
1/3 lb. 1-1/4" drywall screws...$3
100 1/8” pop rivets…$5
1 sheet 1/2” (ok, 15/32) BC Fir…$37
1 pair Enco Workbench Legs…$27
-------------------------------------------
Current total, $100

 

[KEH]

You should come out all right, don't know about how light it will be. You are using a full sheet of plywood plus a bunch of steel, but it will be strong. I think it will hold more than 300 pounds.

Theory of operation of a woodworking bench is a little different than a mechanics bench. Woodworkers don't want steel in the work surface for sharp tools to hit.

Are you going to have a vise? If so, I suggest reinforcing a corner with a small square of steel plate, maybe on both sides to mount the vise on.Dosen't have to be very thick, 1/8 inch should be plenty. Footprint maybe twice the mounting area of the vise.

BTW, the torsion box system gets it's strength from having the framework covered with an outer skin, which the 1/2 inch plywood will provide amply.

KEH

 

[2chipped]

I've often thought about,but never came up with a plan to use a ambalance stretcher as a base. It would pop up and move, but i don't know the weight cap.

 

[mrholeshot]

Build the frame from aluminum with folding legs that lock. make the top from 3/4 plywood. Mount a small vice on one end. Put a handle on the side at the balance point

 

[Bolster]

Great suggestions. I'm taking breaks from building, to read your comments. I knew that putting the collective wisdom of GJ on this would be worthwhile!

I'm conservatively cutting the steel studs 1.5" short of my final desired dimension, I don't want the frame to go over the 8' panel size, that would be a disaster. I'd rather trim the plywood to size.

Here joining a C-section to a G-section with pop rivets, staggered up and down, about every 6".

Now how to join the face of G to the face of another G? It's just for convenience, because no strength is needed. The strength comes from the ply panels being screwed on. Honestly, packing tape would probably do the trick. I opted to tack solder about 5 times along each length. [EDIT: Packing tape is actually a better idea. It's more flexible and the solders won't break.]

 

[Bolster]

Progress. Frame complete. About 75 rivets. Eight foot frame weighs 17 lbs. Remember the 10 ft C sections? They provide enough extra that they make up the 22.5" end sections of the frame. The other cross members are G sections. With the 8-ft design you pretty much use it all up.

Now fastening top plywood. Wafer head screws require each to be countersunk with a forstner bit! Slow going. [EDIT, I toss the waferheads, not working.]

 

[iandh]

I have two personal dreams since I also work in situations like yours... these I've been thinking about for years. Now that I'm working for myself and have freetime, they may actually happen.

1) A toolbox integrated to a wheel dolly. When in mobile mode, the toolbox would roll around just like one of those roller suitcases. Once on site, the toolbox would slide up the two dolly uprights, locking into place at a comfortable standing working height. When you're done, you step on a foot pedal to unlock, and then slide back down.

No more bending over to the ground to grab tools while on a job. You walk right up and open a drawer just like you're at home with your top box on your rollaaway.

2) Similar to what you're doing, a portable workbench. Mine would fold and attach to the front of the toolbox dolly, and would act to lock the drawers in place when in mobile mode.

Once you reach the jobsite you remove the folding workbench, set it up, and then raise the toolbox to working position.






I've thought about it for some time and I think it could be made into a wonderful ergonomic setup.

 

[Bolster]

Sweet dreams are made of these....!

Sounds like you hate bending over a hundred times a day, as much as I do!

 

[iandh]

Sweet dreams are made of these....!

Sounds like you hate bending over all day, as much as I do!

Yeah, it might sound convoluted to some, but I have nerve damage in my back and dominant arm from a car accident, and bending down to dig through a tool bag for something is my worst nightmare.

If I could have a working setup like described above, it would change my life.

 

[Bolster]

Iandh, do it!

Project update: Not happy with these waferhead screws I'm using to mount the plywood. They don't take much torque, and some have already stripped out... seems to me the thread is too fine and the minor diameter too large.

Wonder if plain ol' drywall screws would do better (with a pilot hole)?

[EDIT: They do. Fine thread drywall screws took much more torque.]

 

[KEH]

Looks good, I repeat my comment about it hilding up more that 300 pounds.

On screws, suggest you fing one of the places that builds or assembles those little steel buildings out of tin panels screwed to thin steel framing. You might get some advice from them about the self tapping screws. Minor diameter does look a little large.

Side note: some cheaper hollow core doors have the inner torsion supports made from thick honeycomb cardboard with the skin glued to the cardboard.

KEH

 

[Bolster]

Gracias. My 300 lb ceiling number is coming from Enco, who say that's how much the legs are rated for. We'll see.

Wife stuck her head into the garage, considered it for a moment, and said, "But will it fly?" Funny girl. Does feel I'm building an airplane wing.

Tossed the wafer-head screws, went to plane jane 1-1/4 fine thread drywall screws (drilling a pilot hole first). They allow much more torque, and don't require difficult forstner countersinking. Still I would not want to depend on any single screw too much; this is definitely a "more is better" sort of fastening project. Each side taking almost 70 screws. Maybe one step above cardboard and glue shocking.

Project stalled, as paying work has come in.

 

[Bolster]

Sorry for the slow update. Finally got back to work on the torsion box bench. I did a mid-course correction and shortened its length from 8 feet to 6. I changed my mind and decided I really did want to be able to close the tailgate after I put it in the truck, so I had to go back and re-engineer the frame a bit. The metal frame netted out at 13 lbs when done.

The legs arrived from Enco. They were not cross-braced as Enco's catalog illustration showed, and thus quite wobbly. A cheesy explanation from the manufacturer of the legs (which I discovered to be Ebco Products of St. Louis, after the legs had arrived) explained how they had "removed the cross braces to make the legs even sturdier." I understand that manufacturers occasionally spit in your coffee, but why do they have to tell you it's creamer? So +$20 of hardware and 3/4 aluminum for cross bracing the legs set it right; they are once again rigid. The legs bolt into the bottom of the table, into threaded nuts for repeated ***'y and disass'y. I also added cross brace cabling between the legs, which required some additional reinforcement of the legs, and added an aluminum stretcher.

I am complaining about the legs, BUT they are now strong and lightweight. The result is a remarkably rigid, lightweight bench at a cost of around $140. When I hop on top of it, it shrugs off my weight as if it were nothing. I have no idea what its weight bearing capacity is. Seems remarkably stable against pushing the ends of the table, as will happen when doing vice work.

The bench netted out at 63 lbs total and disassembles easily (8 bolts & 2 turnbluckes). It's not featherweight, but it's easy enough to heft the 50 lb top around by myself. Especially after I attach the handle to the side.

Now it needs a finish, I'm thinking an outdoor urethane.

Any ideas of upgrades or improvements at this point?

 

[jrod60]

Snazzy bench. Leveling feet with a pretty large pad might be good if you don't want to haul around a bunch of shim packs.

 

[WheelsNT]

Does anyone make leveling feet that would allow you to connect a cordless drill to the upper end of the leveling pin? One of those hex-shafted quick connects would be great. I'm just trying to think of a way to adjust the feet quickly with a power tool. Leveling feet are always a pretty fine thread, which does allow precise adjustment on a flat surface. But on a less-than-flat outdoor surface, it always takes a good deal of twiddling each foot by hand to get them flat.

 

[Bolster]

I forgot to add: Happy 4th of July! This is a photo I snapped last night at Long Beach. It has absolutely nothing to do with this project.

Adjustable feet would be nice. If I find any lightweight ones I may do that. I wonder if just ONE adjustable leg would do it? The other three would act as a tripod.

 

[Garage_Mahal]

1) A toolbox integrated to a wheel dolly. When in mobile mode, the toolbox would roll around just like one of those roller suitcases. Once on site, the toolbox would slide up the two dolly uprights, locking into place at a comfortable standing working height. When you're done, you step on a foot pedal to unlock, and then slide back down.

No more bending over to the ground to grab tools while on a job. You walk right up and open a drawer just like you're at home with your top box on your rollaaway.

2) Similar to what you're doing, a portable workbench. Mine would fold and attach to the front of the toolbox dolly, and would act to lock the drawers in place when in mobile mode.

Once you reach the jobsite you remove the folding workbench, set it up, and then raise the toolbox to working position.

This and this may get you close to your dreams. (OK, the vinyl table is a joke . . . but they are pretty tough.) I'm planning something similar. I want to mount a top box to a elevating cart, like the one shown in the link, to serve as a mobile service cart for when we go racing or around the shop. It should roll up and down the trailer ramp and be secured quite nicely.

 

[beardking]

I may have missed it, but are those legs folding or static?

 

[Bolster]

Static bolt on. I can't imagine a lightweight folding option with sufficient rigidity for a bench. The bench disassembles with 6 bolts holding on the legs, 2 holding on the spreader, and loosening the 2 turnbuckles. Takes under 5 minutes to reassemble.

I also have considered the hydraulic lift carts, but couldn't find them light enough. Lightest ones I could find were around 100+ lbs, they would hold only 300-500 lbs, and they'd be difficult to chock sufficiently for bench work. Also the surface tops were small, around 2-1/2 feet. Would require stooping as work surface would be low. Also insufficiently rigid for bench work when raised. They're really not designed as bench substitutes, they are lifting devices.

 

[scarrylarry]

Bolster

Bolster, that is an excellent work bench you have made for yourself!
Congrats!
scarrylarry

 

[Mr.Nutcase]

I asked one of my instructors for recommendation, on making workbwnch, he said
that wood is not good choice for a shop. He recommend a metal 3/16 to 1/4 on top of the wood product....

 

[y'sguy]

I don't even need a portable workbench and NOW I wanna build one. HA

Couple of ideas I got while looking over your great idea!. why not build the whole top from arch aluminum channel, say 3" width or maybe 4" and instead of steel studs (more costly I know) and then sandwich all together with Lords gLue and don't use ANY screws. Just bonded, aircraft style! use formica laminate for the surfaces and fill it with urethane foam. Would that work.

 

[fireguy]

The folding table legs are available separatly. Then you could make your own table top to whatever size you need. I have had tables made of steel to hold appliances. The legs made of angle iron, with flat stock on the end that rests on the floor. The flat stock was drilled and tapped for a 3/4 carriage bolt. The round head makes the table adjustable for level and does not dig into soft vinyl floor covering.

I kept finding I needed a work table in resturants. It needed to be small, portable and cheap. I found 2 of plastic folding sawhorses. I then used a piece of plywood, about 2 x 3 feet. I put 2 runners of 1 x 2 on for stiffness, cut hand hold on all 4 sides. I can grab the top and both sawhorses and make one trip into the kitchen. It is not very big, but working space space is often limited in a resturant. My portable tool table will hold my service manuals, or my tool box and pipe fittings. The runners also allow me to put the table top directly on an appliance. A bungee cord keeps it and the legs against the sidewall in the van. If I need access to the shelving behind the table, the bungee cord allows me to tip the table top for access. When the table gets dirty enough, it will be recycled into firewood.

Mine is not as fancy or as strong as yours, but it fits my needs.

 

[TireTracks]

You could if you felt so inclined, add a set of rubber wheels, and a handle on the other end, so you could fold it up and roll it back to your truck.

 

[beardking]

The folding table legs are available separatly. Then you could make your own table top to whatever size you need. I have had tables made of steel to hold appliances. The legs made of angle iron, with flat stock on the end that rests on the floor. The flat stock was drilled and tapped for a 3/4 carriage bolt. The round head makes the table adjustable for level and does not dig into soft vinyl floor covering.

I kept finding I needed a work table in resturants. It needed to be small, portable and cheap. I found 2 of plastic folding sawhorses. I then used a piece of plywood, about 2 x 3 feet. I put 2 runners of 1 x 2 on for stiffness, cut hand hold on all 4 sides. I can grab the top and both sawhorses and make one trip into the kitchen. It is not very big, but working space space is often limited in a resturant. My portable tool table will hold my service manuals, or my tool box and pipe fittings. The runners also allow me to put the table top directly on an appliance. A bungee cord keeps it and the legs against the sidewall in the van. If I need access to the shelving behind the table, the bungee cord allows me to tip the table top for access. When the table gets dirty enough, it will be recycled into firewood.

Mine is not as fancy or as strong as yours, but it fits my needs.

Fireguy, could you post or PM me pics of your portable table? That sounds about perfect for something my brother could use on his kitchen installs at his job.

 

[scheu]

Sweet!

 

[Stuey]

Looks great!