Chassis/Cage Tube Clamps (notch style from Summit Machine)
 

http://www.summitmachine.com/index.p...tomParts&cp=tc

Summit Machine part # SM-TC-1500 For 1-1/2" ID .120 wall tube - will fit 1.75" .120 wall

Ordered the wrong size (need 1-1/2" OD, not ID). I have 8 available

"Tube Clamps are used to create strong removable sections of tubing. Tube Clamps give you the ability to move or remove sections of tubing, while retaining strength and durability when mounted. Comes as 2 pieces with hardware."

http://www.summitmachine.com/images/...TubeClamps.jpg

Located near Portland, OR. $30 shipped each (two halves & fasteners for one joint- same as picture)

sold.