Cheekbender—Pittsburgh
The Cheekbender turns a 90 Flange that serves as the Male Pitts on a Square Throats of a Rectangular Duct Elbow.
Square elbows have two sides, referred to as “cheeks”. While those cheeks are still in the flat, the manual cheek bender turns a 90 degree flange on each of the two sides of the throat. One side turns the flange for small Pittsburgh (1/4” high) and the other side turns the flange for large Pittsburgh (7/8” high). This flange will serve as the Male Pittsburgh.
Radius and Square back elbows have 2 Cheeks (sides), one Wrap (the backside of the Elbow), 2 Heels (the upper seam of the Elbow) and a Throat.
The Throat can be either radius (so it’s basically just a short version of the Heel) or it can be square. Interestingly enough, to make a Square Throat requires that a shop have a Cheekbender. This machine, usually sold as a 24” long and hand operated has two sides each with a handle. One side turns up a 90 degree flange 1/4” high and is used for standard 20 ga Female Pitts; the other side turns up the 90 degree flange 7/16” for “larger” female Pitts seam, usually an 18 ga Pitts machine.
Why is it only 24” ? Throats of Square elbows are typically small; it would be rare to have any longer than the 24” that the machine accommodates.