Assembly table

[Jaromir Svoboda]

I am building new assembly table and need help with table top.
Table is about 30 x 60",legs are 3 x 3",rails are 1 1/2 x 3 ".
I like these three options:

1.Old grow pine,its 3" thick,from old barn build in 1887.

2.Torsion box,with white melanine on top.

3.Torsion box, with 3/4" hardwood floor on top.

I like the idea with hardwood floor.I can get brazilian teak or cherry from Craigslist for few dollars.

[Jim O'Dell]

Jaromir, for an assembly table, you want flat. So if the old growth wood would stay stable after you flatten it, that would be neat. But possibly a lot of work. I'm also contemplating an assembly/finishing table now that I've got that room finished out, and cleaned out. I will likely make my table a little larger, mobile, and with High Pressure Laminate on top. It will probably be a torsion box design using 3/4" MDF. Hope to find a not too expensive way to adjust the height, and a way to make a system that I can clamp parts down (T-track most likely) for assembly and a corner and two sides that have a lip to help square face frames. Your idea of using laminate flooring sounds nice, but will it stay flat? You would also have to make provisions for movement as it will contract and expand at different rates than the sub base material. Jim.

[Robert Chapman]

When I built my work bench about 10 years ago I used three laminates of 3/4" particle board and covered that with 1/4" tempered masonite. This makes a flat, heavy, durable and stable top which has served me well.

[David Giles]

Mine is a roll around assembly table with a granite top. Dead flat and weather resistant for outside storage. Scrap granite pieces are common and relatively inexpensive if you're not picky about the color.

[Jon Endres]

I'd build a torsion box out of MDF with a sheet of melamine or tempered hardboard on top. The melamine is nice because you can mark on it with dry erase markers or pencils.

[Dave MacArthur]

Remember for a "torsion box", also known as a "stressed skin box", you must have a top and bottom skin that is a SHEET, that will allow transmission of downward force into sideways force to equalize the load. If you're just putting hardwood flooring ON TOP of a fully built torsion box... well, it might work, but it might also expand/contract and if glued down to top skin would likely cause it to warp out of flat.

If you're thinking of using the hardwood flooring as the top skin itself, no, this won't work. Also, just like a veneered sheet, you must have the same skin on top and bottom of torsion box so any movements are counteracted. If you put two materials that expand/contract at different rates, you'll have built what is usually known as a "Warped Box", generally used for firewood.
Good luck

[Kent A Bathurst]

........Old grow pine,its 3" thick,from old barn build in 1887.........

I don't now what the condition is of the old growth pine, but it must be relatively OK for you to consider it for the bench.

Except - if I had that wood, I would never use it for the workshop [this coming from the guy with a back bench of hard maple - 2" x 26" x 14', clamp racks made from walnut, plane + saw till from QS sycamore & walnut.............]

The old growth pine is a rare breed. Maybe use it for something else............

[Jaromir Svoboda]

Top and bottom skin is 1/2 MDF,torsion box is made from 3/4 plywood 1 1/2 wide,and then I'll put 3/4 melamine on top.

[Brian Tymchak]

.... and a way to make a system that I can clamp parts down (T-track most likely) for assembly...

Jim,

+1 that a torsion box is the way to go for assembly tables. I've never built one and don't fully understand all the physics involved, but I'm wondering about something. Assuming I'm understanding your comment to be that you would cut a dado into a skin for T-track, won't that defeat the purpose of the skins to balance the stress top and bottom? Not a criticism, a real question that I might learn something.. If it works, I'll likely do the same.

Thanks, Brian

[bradley strong]

I recently built an adjustable height assembly table with torsion box top with laminate backer sheets that were free from my plywood supplier. They come on top and bottom of every order of laminate they receive. They usually get tossed, but they gladly saved them for me. They have a little texture to them, but I like it.

The most important thing, other than flat, for an assembly table is that glue doesn't stick to it.

[Dave MacArthur]

Hey that's looking like a nice table! I've got one right now that is two full doors side by side... it's huge, and I need to break it down and use the parts to build up something more reasonably sized for my 2 car shop. Got it thrown in with a SawStop purchase and it's matched for it as an outfeed table though, so hard to get cutting... You're getting me motivated though!

[Jim O'Dell]

Brian, you are correct that it would change the engineering needed for a torsion box to stay stable and flat. Maybe I'll change the t-track to be in the pieces that form my lip, and make it wider and maybe out of hardwood. Good catch! Jim.

[Keith Weber]

Not sure if there's a practical reason for using the pegboard on the sides, but your table looks nicer than what the pegboard offers. I would replace that with a couple of nice 1/4 plywood panels. It wouldn't cost much. But, that's just me -- I hate the look of pegboard. Other's opinions may vary! I agree, I wouldn't cut a T-slot in the top sheet -- it would compromise the structural integrity. You could glue 2 sheets of 3/4" to the top, and only put the T-slot in the top one as an option.

Keith

[Steve Jenkins]

I have several torsion boxes I built over the years for different uses. My assembly bench is 4x8 and I built it 18 years ago. Still flat and it just sits on a couple sawhorses. If I neeed a raised edge I simply screw a piece of 3/4 ply to the side of the bench and let it stick up however much I need. That way I'm not having to deal with a raised edge all the time which can get in the way.

[Brian Tymchak]

Maybe I'll change the t-track to be in the pieces that form my lip, and make it wider and maybe out of hardwood.

Ah! I like that idea. Thanks!