I like the looks of sway backed saws so one of the tasks is to turn this straight backed saw into a sway back. Here is the result of the first pass, and you can see that, compared to the 20” D-8 panel saw, that the handle half of the blade needs more curvature.
You can also see the how much higher my handle hang angle is. A boo-boo. I don’t know enough about saws to know what effect that will have.
Addendum: I played around with some saws and I think the D-8 hang angle is optimized for sawing on a sawbench (see Christopher Schwarz’s Using a Sawbench). No surprise there I suppose. I saw with the wood vertical (like cutting dovetails) or clamped to the bench, so the the hang angle is too low for me and I have to tilt my wrist down more than is comfortable. So a higher hang angle is better for my use, even though I should get with the program and get a sawbench.
I chopped off the toe of the saw to remove the hang hole (for aesthetics) and rounded the top of the toe. I eye balled the curvature of the sway, drew it with a sharpie and rough cut it with tin snips. Then I used my bench grinder to get close to the line. That left a pretty bumpy back, so I “jointed“ it with a file. This is the same idea as using a jointer plane – a long surface to even out the high spots. It works nicely (and quickly) on this curve. That got the bumps but there are some waves left. For that, I use an even longer “bump detector”, a metal meter stick. I just hold it flat on top of the blade and press down. The stick will conform to that area and the low spots are easily seen and can be corrected. Repeat over the length of curve and it will be very smooth.