Simontonco balance

Thanks for posting with images. Our 15-199 pivot shoe looks similar to your shoe. Take a look. There are some cases with Simonton pivot shoes, that you may have to reuse the metal center cam to work with your sash pivot bar.

They will be 1/2"-wide Series 160 coils. You need the spring weight number stamped on the coil when ordering, so take a look and try to find the stamps.