Legs for assembly table?

[Aram]

At some point, I really should make an assembly table. I want it to be flat and durable, but simple and something I can build in a day or so. Let's say 3' x 5', 30 - 36" high or so. I will want to clamp things to the top, so no aprons allowed. I'll want a shelf partway up the legs to store stuff. For the top, I'm thinking a very simple torsion box. 1/2" ply on top and bottom, plywood strips on edge for the sides/ends and the ribs on the inside. Wax on top, done.

What would be the simplest, easiest ways to make legs? Figure I'll need adjustable feet for a non-flat floor. Also figure that sooner or later, I'll climb up on this thing. It would be bad if it broke.

My initial thought was 2 x 4 (or 2 x 6, whatever), laminated to double thickness, and cut to length. Adjustable feet on the bottom, maybe the kind where you tap in a T nut. How to attach the legs to the top? Maybe L-brackets and screws. Maybe screw oversized plywood to the tops, then screw the plywood to the underside of the tabletop. Adding a shelf would be easy. But I'm not convinced any of that would stand up after being climbed on.

Thoughts?

Thanks in advance.

[DaveR1]

I expect it would work as you're thinking although probably built like a brick outhouse.

I might do something like this. Plenty of overhang for clamps, easy enough to add a shelf and if you're really worried about support, run a middle stretcher between the long rails. Instead of monkeying around with laminating 2x4s I'd just use 4x4s.


Actually, I think you could make a sufficiently sturdy table with plywood legs if you wanted.

[Mike 55]

At some point, I really should make an assembly table. I want it to be flat and durable, but simple and something I can build in a day or so. Let's say 3' x 5', 30 - 36" high or so. I will want to clamp things to the top, so no aprons allowed. I'll want a shelf partway up the legs to store stuff. For the top, I'm thinking a very simple torsion box. 1/2" ply on top and bottom, plywood strips on edge for the sides/ends and the ribs on the inside. Wax on top, done.

What would be the simplest, easiest ways to make legs? Figure I'll need adjustable feet for a non-flat floor. Also figure that sooner or later, I'll climb up on this thing. It would be bad if it broke.

My initial thought was 2 x 4 (or 2 x 6, whatever), laminated to double thickness, and cut to length. Adjustable feet on the bottom, maybe the kind where you tap in a T nut. How to attach the legs to the top? Maybe L-brackets and screws. Maybe screw oversized plywood to the tops, then screw the plywood to the underside of the tabletop. Adding a shelf would be easy. But I'm not convinced any of that would stand up after being climbed on.

Thoughts?

Thanks in advance.


On a outfeed table I used 3/4 black pipe and flanges. The one at the top was screwed into the table and one at the bottom for the foot. It was very sturdy and adjustable at both ends. It was quick and cheap to build. 

[jteneyck]

When I was thinking about building an assembly table I based it on two 1/2 width Paulk type tops, sitting on rectangular plywood boxes, whose sides were of different width.  That would give me a large top, a small top, or two tops with a gap between them, on a low base or a higher base, in any combination.  Never built it, but it was perfect in my mind.  

John

[Aram]

I expect it would work as you're thinking although probably built like a brick outhouse.

I might do something like this. Plenty of overhang for clamps, easy enough to add a shelf and if you're really worried about support, run a middle stretcher between the long rails. Instead of monkeying around with laminating 2x4s I'd just use 4x4s.


Actually, I think you could make a sufficiently sturdy table with plywood legs if you wanted.

I ruled this out at first, because it kind of violates the apron rule. But you know what? You're right, this would work and is probably the easiest solution. Thanks.

Mike 55, I couldn't quote you but thank you for the suggestion.

[iclark]

For the top, I'm thinking a very simple torsion box. 1/2" ply on top and bottom, plywood strips on edge for the sides/ends and the ribs on the inside. Wax on top, done.

If you are going to build a torsion box top, why not build it with 4 square holes in the bottom for legs to slip into?

Cut a tenon on the top of each leg so that the bottom of the box sits on the shoulders and build the interior webbing so that it forms a snug mortise for the tenon to fit in.

If you are considering standing on it, I might chicken out and use something a bit heavier that 1/2" for the top of the box.

I might also use a heavier plywood for the outside edges if you might put a lot of clamp pressure on the edge.

It would probably be a good idea to mark the edges/outside with the web locations so that you can line the clamps up on a web.

Cutting the legs off a few inches below the shelf would let you use the pipe-with-2-flanges on the bottom of the legs to adjust for uneven floor (or, you could just make the legs the same length and use shims under them if you are not going to move it around a lot).

[Aram]

If you are going to build a torsion box top, why not build it with 4 square holes in the bottom for legs to slip into?

Cut a tenon on the top of each leg so that the bottom of the box sits on the shoulders and build the interior webbing so that it forms a snug mortise for the tenon to fit in.

If you are considering standing on it, I might chicken out and use something a bit heavier that 1/2" for the top of the box.

I might also use a heavier plywood for the outside edges if you might put a lot of clamp pressure on the edge.

It would probably be a good idea to mark the edges/outside with the web locations so that you can line the clamps up on a web.

Cutting the legs off a few inches below the shelf would let you use the pipe-with-2-flanges on the bottom of the legs to adjust for uneven floor (or, you could just make the legs the same length and use shims under them if you are not going to move it around a lot).

I did consider the corner cutouts. It could be strong for sure. Also seems like... work....


You might be right about the the plywood thickness, but torsion boxes are pretty strong. I dunno. 

The pipe idea is appealing, thanks.

[iclark]

The cutouts do not have to be in the corners. If you want, you can put an overhang on the corners.

yeah, it does add more work to do the mortise and tenon approach for the legs, but it does simplify all of the attachment stuff. You could also not glue the legs into the top. That way, you could break it down for storage or moving if needed.
You are making me think.

[mike4244]

At some point, I really should make an assembly table. I want it to be flat and durable, but simple and something I can build in a day or so. Let's say 3' x 5', 30 - 36" high or so. I will want to clamp things to the top, so no aprons allowed. I'll want a shelf partway up the legs to store stuff. For the top, I'm thinking a very simple torsion box. 1/2" ply on top and bottom, plywood strips on edge for the sides/ends and the ribs on the inside. Wax on top, done.

What would be the simplest, easiest ways to make legs? Figure I'll need adjustable feet for a non-flat floor. Also figure that sooner or later, I'll climb up on this thing. It would be bad if it broke.

My initial thought was 2 x 4 (or 2 x 6, whatever), laminated to double thickness, and cut to length. Adjustable feet on the bottom, maybe the kind where you tap in a T nut. How to attach the legs to the top? Maybe L-brackets and screws. Maybe screw oversized plywood to the tops, then screw the plywood to the underside of the tabletop. Adding a shelf would be easy. But I'm not convinced any of that would stand up after being climbed on.

Thoughts?

Thanks in advance.

4x4 legs, pick lumber that is straight grained and light in weight. Mortise each leg for two stretchers at 90° . One stretcher for the length and the other for the width. You need 4 pieces total. Cut double tenons on 2x6 stretchers. Make tenons 1-1/16" thick and 3/16" short of the mortise depth. Bore 3/8" diameter holes in the posts only. One hole per tenon   is for a peg ,explained later. Install the pieces dry. 
Make sure the joints are tight. That is the reason the tenons are 3/16" shorter than the mortise, so you have room to pull joint tight.
Now mark the hole you drilled thru the leg into the mortise with either a 3/8" transfer punch or a 3/8" auger or brad point bit to mark the hole.
Undo the pieces. Bore a 3/8" hole thru the stretcher 1/16" off center away from the leg. Very important that the hole center is offset away from the leg. When you install the stretchers into the leg you will see that some of the hole you bored is not centered. Now drive a 3/8" x5" dowel with a dull point ( I use a pencil sharpener) into the leg and thru the stretcher. This will pull the joint tighter than a cows butt at fly time. 
repeat for all the posts and stretchers. This construction is called " draw peg" construction and has been used for hundreds of years. 
When done, cut the excess pegs off . You can leave the pegs 3/16" proud of the leg and round over the peg with a sandpaper stick if you want.
When the peg enters the hole it bends a bit as it pulls the joint tight. Some people put glue on the draw peg, I do not think it is necessary.
The top can be fastened in several ways. First make your top overhang the frame so you can use clamps on the edge . You can use angle irons with holes on each leg like some Simpson hardware. T type fastens to inside of the leg and the top's bottom surface.
I used wood buttons , rather than explain this do it the simple way with hardware.
The frame will hold a lot of weight. If the table is for woodworking I would make the length 72" and the width 28" or less.
Make the height so it is comfortable for you. 30" should be good for a person 5'-10" or less. 36" for taller men. 
I used to make assembly benches for manufacturing companies. Most of the employees were women. Benches were 28" high and laminated softwoods for tops. These benches were 28" wide and 78" long. Foot rests were built into the frame. 
It will take several days to build  bench like I described. I could do it in one day, I have the tools, knowhow and experience. At least 200 benches over the years not counting 7 woodworkers benches with dog holes, one or vices  and built in tray in the top.
Don't be discouraged if it takes longer than you expected. You can buy maple or beech laminated tops if you want, not cheap but would save you time and they look good too. 

mike

[DaveR1]

I ruled this out at first, because it kind of violates the apron rule. But you know what? You're right, this would work and is probably the easiest solution. Thanks.

You're welcome. In case you haven't built it already, here's another option. Probably a little faster to build and it would get you more overhang on the sides if you felt the need for it. A little less likely to bang your shins on the long stretchers, too.
Middle stretcher optional.