There are lots of great projects listed here on Instructables, but what fun is that if you don't have a work area on which to try building them?
If you're like me, then you're probably working at the kitchen table, or at the computer desk and that doesn't cut it. I needed a bench. Not a bench to smash things against, or to hammer on... something light duty with a small work surface, good lighting, lots of AC outlets, and most importantly - compact.
That's where the idea of a folding hobby bench came from.
Step 1: Constraints
I had a place where I could put my bench, but it couldn't stay there permanently. I needed the option of tucking it away in a closet to "neaten up" for company etc.
My space was 30" wide, so I would design my bench to be 29" max width. Tabletop height would be comfortable to work at while seated - I based this on the height of my computer desk at 29" from the floor to the top of the table. I figured a decent sized working surface would be at least 12" deep. I also had a powerbar that I wanted to mount, and I thought some shelves would be handy for small parts etc. I wanted this thing to fold as thin as possible, and I figured if I could design it to be 4-5" thick when collapsed, that would be reasonable.
Those were my basic requirements.
Step 2: Materials
Another motivating factor for building the bench was a free supply of 3/4" "wood" I had access too. The wood looked like a balsa core plywood with a thin veneer (junk), but it held screws rather well and it was extremely light compared to similarly sized plywood. I salvaged a few sheets.
1. * 3/4" sheet wood - cut to size according to prints
2. Three piano hinges (24" lg, 1/2" band or close)
3. Wood glue
4. Supply of 1/2" and 1-1/2" wood screws
Step 3: Design
My basic design was to have folding legs and tabletop that would allow me to collapse the bench.
In the 1st picture you can see that the left leg is hinged inwards, and the right is outwards supporting the tabletop. Originally I thought I would have more shelving, but I didn't see the need for it in the end.
The 2nd picture shows the legs and top collapsed and in this state, the bench is only 5" thick making it easy to store in a closet, or under a bed.
Step 4: Assembly
I first made an assembly that I called the base. It consisted of the frame for the bench including:
a. rear legs
b. top shelf and back section of tabletop
c. cross beams at table height, and along bottom
d. backing panel (to mount power bar etc. to)
All of the joints were first glued and then wood screws of the appropriate length were used.
The folding legs were then attached using two piano hinges screwed to the inside seam such that they would hinge inwards.
The top was then attached using the third piano hinge mounted to the underside such that the top would fold downwards and hang. When folded up, the top will hold the legs against the back of the base to keep them from flopping around.
When mounting the piano hinges, the edges of the wood should first be schamfered by about 1/8" or so at a 45 deg to give some clearance for the hinge pin. You'll see what I mean when you put it together.
Step 5: Finished Product
Even though I used low density "wood" of fairly low quality (although it looks good!), this bench is really stiff and doesn't flex at all. You'll find that the piano hinges are fairly flexy, but once screwed into place, they're rigid. I only put screws in every other hold on the hinges (about every 4" or so).
I do have some finishing touches to implement, but I haven't gotten around to it yet.
1. I have a nice piece of masonite (1/4" thick, smooth surface finishing wood) that I'm going to use as a writing surface if I need it. The idea is the piece can be slid into place when needed, and then stored on the back of the bench by hanging.
2. Although this hasn't happened yet, the legs can fold outwards if kicked. They usually snag on the carpet before moving though. This can be prevented by installing some dowel or small blocks on the underside of the tabletop's side edges to keep the legs from over extending.
3. I plan on cutting a hole in the back to run the power cord through to get it out of the way.
4. If I find a small florescent light, I'll install that as a permanent light to get rid of the lamp on the tabletop.
Good luck with yours and I hope this helps someone looking for a nice little hobby bench!