It's getting harder to find traditional bowstring makers locally. Your best bet is to order custom strings online from a specialty shop that caters to traditional archery.

Companies like 3Rivers Archery or Lancaster Archery are great resources. You'll need to know the exact bow length (which you do) and the brace height to get the right string length. They make high-quality Flemish twist and endless loop strings that will be perfect for your classic Bears.

These shops understand traditional gear and will be able to help you get the right strings for your great old bows.