J.D. Darlington Backsaw - Not Usable

J.D. Darlington was a line of saws by Harvey Peace. It's a nice little saw. Everything, including the split nuts, is in good shape. However, the teeth kept breaking while I was sharpening it. I jointed the teeth down several times and the same think kept happening. The metal must be too brittle. It's still a nice example for a collection.