The Dragonfly

Last Update-03/13/2010 01:40 AM      

Up until now I have been able to create the parts I have needed on a small bench mounted on a few movable saw horse's.  I find that most of the time smaller benches work well as they can be moved and adjusted to any position needed.

After many hours of thinking of a good way to build the nice flat, sturdy 4 x 12 bench needed for the rest of the plane from the stuff that Lowe's and Home Depot calls "Wood", I had an epiphany. 

I have built benches in the past constructed from steel stud and the matching track they use to build commercial walls.  Usually I had a solid object, like a stud wall in my garage, to attach the stuff to that would enable it to be sturdy and straight.  In this situation, I didn't have a solid structure to attach it too, nor did I want it against a wall. 

Then the Epiphany!  Why not build a 2x4 frame unit that was in itself as straight and sturdy as possible without going overboard and then "float" a table constructed of steel studs and track inside the upper frame.  This way, the "frame" could flex and take the shape of the concrete beneath it before the table was placed in the frame, then leveled and securely attached.  This saves me from spending hours wedging and fiddling with individual legs.  Here's what I did.


I first started with some 2"x 4" x 12''s I cut to 141 inches in length.

Then I added two 48" Ends to form a frame.  The 8 legs are 31.75 inches long, attached to the corners and every 3 feet on center down the length.

Two more 141" 2x4's  are attached 5 inches off the ground  to the lower legs for the bottom support.




 Here is what the frame looks like squared up and ready for the "floating table"             






I bought four pieces of 10' track.  I needed the track to be 141" in length so I cut two more pieces 27 inches.  You'll notice in the pics that I cut the flanges back something like six inches.  When you do this, you can lay the short piece into the long piece and the ridges will self along making it straight.  I used six 1/8" Avex pop rivets to secure the pieces together.




Here I clamped the track to the inside of the frame with about an inch of track above the frame edge.






Next, I cut 10 studs to 44 7/8" and installed them into the track on 16" centers just like a wall laying on its side.






Using this method almost self aligns.  I attached the stud to the track using self tapping screws on the bottom and countersunk pop rivets on top so the MDF table top will lay flat.





The track and stud are so stiff, you can simply loosen the clamps and level the table in all directions.  You will quickly notice that the frame is not flat at all, but the table is perfect. (If you leveled it right). I drilled some 1/8 in holes inside every other bay in the track and attached the track to the  frame with 1" screws.




I like to use 3/4" MDF as a table top because it is hard and flat.  The MDF is actually 49" x 97" so it will overhang one edge about one inch. I will attach the top to the table with some 1/2" wood screws.




This thing is amazingly flat.  I'll add the other 4 foot piece to the top and some 1/2" plywood across the bottom for storage to complete the 4 x 12 bench.




Here she is all covered up.  I decided to add some .025 aluminum strips on the top of the studs in between the track on each side. The tracks are about  .025 thick so it only causes a very minute(mi-noot)  sag (if any) in the MDF.  It just made me feel better.  I also added four diagonal braces to the upper frame corners on the end to help stiffen the frame a bit.  That stabilizer skeleton looks right at home and ready for its skin!