The most common steel ground adjustable prop for the Stearman is the McCauley D-5926. This is also known as the Army Hub. The other McCauley prop which is approved for the Stearman is the D-1093, which is known as the Navy Hub.
The D-1093 is approved for two different steel blades. The SS-135-6M (a modified Army Blade) and the SS-138-6 (built for the Navy hub). The D-1093, pictured, has balancing sprockets on each end of the hub. These sprockets are screwed onto the hub and held in position by the pin at the bottom of the clamp. The pin goes into one of the depressions on the sprocket. Notice that the clamps are both positioned directly forward, and both will be turned the same way if required for vertical balancing.
With the bottom pin moved back, the sprocket can be screwed in or out a bit, and the clamp repositioned up against the sprocket to give an adjustment in weight balance of either blade. The movement of the clamp and it’s bolt in or out allows a vernier adjustment in horizontal balance. This is much easier, faster and more accurate that disassembling the prop and peening a little bit more lead down the hole in the light blade.
There aren’t very many D-1093s around, because production numbers were much lower. But they are a great propeller.