I see the Robertson bagpipe to the right and think "Whoa. Something is happening here." The severe profile of the tuning chambers is gone. Beading is becoming more rounded and the projecting mounts are huge! Now, was this in the 1930's or sometime later? Truthfully, I don't know however other features of those earlier Robertson bagpipes seem to be gone or diminished.
The projecting mounts are changing from earlier Robertson pipes and we have a mix of casein mounts and catalin rings. Of course, the catalin would have been pure white when new and very difficult to distinguish from the casein. Robertson bagpipes with catalin are uncommon.
This is the Robertson bagpipe clearly in transition. The sides to the tuning chambers are straightening. The projecting mounts are "delicate" relative to what we find later, but still retain the detail next to the bead. The sides to the stocks are straight rather than the bulbous stocks in the 1960's. Also, you can see the beading and combing has changed.
Silver & Ivory above. I love the silver with the raised shield. Black casein and catalin above. Catalin below and then some with wood or black casein mounts.
You'll recognize this from Jim McGillivray's website. Jim and I talk constantly. This was an interesting set. The silver is hallmarked 1938. The drones are a bit earlier and the stocks are 1960's. Still a great horn.
James Robertson 1930's & 1940's