For those that are interested, here is a picture of my Bishop adjustable Model 10 Backsaws. Originally patented by Wuest Jan. 9, 1906 (#809485), it covered a saw plate filed crosscut on one side and rip on the other with an adjustable back. On the toe end is another set of "teeth". These were called a rack and were not sharpened. They were to keep the adjustable back from moving at the toe. These saws came in a variety of sizes. The shorter saws have finer pitch.
The back can be adjusted so that it regulates the depth of cut. A simple lever releases the handle and the blade assembly slides out.
Disston also made a similar model. Patented by Smith Jan. 27, 1914 (1085503). It was basically the same as the Bishop, except the toe end did not use the rack teeth.

From top to bottom:
16" L x 4" W 8PPI rip, 12PPI X-Cut
12" L x 3 1/8" W 10PPI Rip, 14PPI X-Cut
12" L x 3 1/4" W 10PPI Rip, 14PPI X-Cut (Marked E.C. Simmonds)

Bishop Saw Group.jpg

The center saw has a handle I made out of walnut. The saw I bought had a broken handle so I got it cheap. I made the handle so it would fit my small hands.
Here is a picture of the broken handle so you can see some of the weak points.

Bishop Saw Handles.jpg