XYZ Corner Piece

This Skektchup file is an idea for a modular, reusable corner connector that brings three square, hollow framing tubes together at a common point. It might, for example, be an improvement for the present style of corners in the frame of Lifetrac.

I am only a beginner in Sketchup using the free version, so the dimensions are not correct--just giving the concept.  Each of the three "legs" is at 90 degrees to the other two.  The blue circles are holes drilled for bolts;  they would go all the way through each leg but I only drew one "end" of each bolt hole.  You would have to weld the three legs together, slip the long metal tubes over each leg of the corner piece, and then bolt the tubes to the legs.  If through-bolts that go all the way through the tube and the leg will not pull the tube walls down onto the leg tight enough, there are two alternatives:  (A) add metal shims and drive the metal tubes onto the legs with a sledge hammer, drill through the shims,  and insert through-bolts.  (B) You would need to use twice as many bolts--but each is just long enough to hold two thicknesses of metal together.  You would need to insert a nut or bolt inside the leg and then put a matching bolt or nut on the outside of the tube.  To insert these nuts or bolts inside the legs after the tubes are in place, you would need three large holes (shown in red) on the three outside corners of the frame. These red holes have to be big enough to admit a wrench or socket.  
   

Ken Morton