Mercian
I live for the CABE
Hi Brett.
If you've located a Coffin ring, I'd use that until you locate a Sweetheart (they seem rarer).
The question as to when they changed from Coffin to Sweetheart is why I started collecting frame numbers in the first place. At the moment, the last known Coffin is about MG120000 (Feb/March 43), and the first Sweetheart MG134000 (March/April 43). Columbia didn't build all G519's in a block of numbers, they are mixed with other bikes, so in this gap there is less than 14000 G519 bikes. I suspect the change is at the end of one contract, and the start of another, and I am trying to figure out the contracts at the moment to see how this and other ideas work. Your bike is later than this change, so I think probably a sweetheart ring.
In Early 1944, MC (Marine) bikes were produced with the Coffin ring, and it seems some very late MG (Army) may have been too (one example known).
Your bike is a straight bar, and these certainly used the Coffin rings earlier (and later), so it won't look out of place, and someone would have to be a true rivet counter to know the difference. Moreover, if a bike was repaired, it's probably more likely that a replacement sprocket would be a Coffin type, no matter what it was originally.
I look forward to the finished bike.
Adrian
If you've located a Coffin ring, I'd use that until you locate a Sweetheart (they seem rarer).
The question as to when they changed from Coffin to Sweetheart is why I started collecting frame numbers in the first place. At the moment, the last known Coffin is about MG120000 (Feb/March 43), and the first Sweetheart MG134000 (March/April 43). Columbia didn't build all G519's in a block of numbers, they are mixed with other bikes, so in this gap there is less than 14000 G519 bikes. I suspect the change is at the end of one contract, and the start of another, and I am trying to figure out the contracts at the moment to see how this and other ideas work. Your bike is later than this change, so I think probably a sweetheart ring.
In Early 1944, MC (Marine) bikes were produced with the Coffin ring, and it seems some very late MG (Army) may have been too (one example known).
Your bike is a straight bar, and these certainly used the Coffin rings earlier (and later), so it won't look out of place, and someone would have to be a true rivet counter to know the difference. Moreover, if a bike was repaired, it's probably more likely that a replacement sprocket would be a Coffin type, no matter what it was originally.
I look forward to the finished bike.
Adrian