Building Torsion Boxes

For the last 20+ years or so I have had this huge assembly table I seem to always be running in to!  It's been good but since size is limited in my shop I had to revise my lay-out.  I used to be able to leave it down and park my truck on top of it but garages and vehicles have changed.  It's supported by 2 of the old style, Black & Decker Workmates.  Recently Fine Woodworking magazine had a feature about using 2 sawhorses and two narrow torsion boxes for your assembly table and even your work bench.  Another thing is that Larry Yule from A.G. Yule and Sons Woodworking here in Las Vegas gave a demonstration at  our Sin City Woodworkers meeting and showed how to make torsion boxes.  These things prompted me to make some changes in my shop.

Here is a shot of the grid before the top and bottom pieces were attached.  I covered the table saw to protect it from the glue but some went through anyway -- time to wax it again!

I decided to make the torsion boxes out of 1/2" Ultra-light MDF.  The first step was cutting all of the pieces to make the grid.  The overall size of the box will be 4" x 16" x 86".  I tend to overbuild and over plan all of my work so I took the time to lay out all of the lines to help locate the nails.  Even though I'm a die hard, hand tool kind of guy I sure was glad I had a nail gun to drive all of the brads.  Each box has 4 long pieces (86") and then all of the cross pieces.  I basically made two "ladders" for the outside grid sections and then toe nailed the center pieces to tie it all together.  Once that was completed the top and bottom pieces were glued/nailed together.  Usually I curse hot weather but with all of the glue I had to spread I was glad to have a 50 degree or so shop.  I used Titebond III and a roller to slather all of the glue on.  I chose it because it advertised the longest open time which I knew I'd need.

So, here's the completed box.  I knew it was important that it be assembled on a flat surface and the table saw is the longest, flat surface I had.  All that's left to do now is screw on a sacrificial piece of masonite (easy to clean off glue) and make pieces to rest it on so that it will also function as an outfield table for the saw.  The other thing I'll do is trim the top even with the sides, left it slightly oversize so I could do this.  I may get crazy and give it a coat of shellac too.