Glad that you're making progress, and I hope a couple of suggestions will be helpful.
1) I'd ask Greg Parker, Sheldon Brown, and Peter Jon White about getting what you want.
2) IF you are able to find the final drive ring, grab it regardless of whether it has the holes at 55 mm. It is no big deal (particularly if you have access to a drill press) to carefully center your transfer cog and use it as a guide to drill the requisite holes. Even countersinking the outside can be done with a drill press and some care. I've done an extra circle on TA cyclotouriste cogs sometimes, since otherwise they tend to "warp" backwards.
3) If you can't find the 1/8" cog, in my experience with a Stronglight on a fixed gear, you can get away with running a 1/8" chain on a 3/32" chainring for lots of miles. If you don't point it out, it is not very obvious.
3) Today's weird factoid: Somewhere buried in my box of chains there are two really odd items. One is a chain that is between 1/8" and 3/32", if I recall correctly, and seems to have been made to allow some French mfgs. to use thicker steel crank sets with newer FW and derailleurs. Never saw a designation for it, but I don't think my memory is failing on this. The other odd bit was a half-link, but I can't remember whether it was 1/8" or 3/32". One end was an "outer" plate set, and the other was the "inner." For getting that rear wheel within 1/4" of exactly where you wanted it. Who says we're fussy, huh?
harvey sachs mcLean VA
+++++++++++++++++++++++++++++++++++++
Duncan Granger wrote: OK, I know this is a long shot, but what the heck.
The Hobbs of Barbican Blue Riband Tandem project is moving along well. Thanks again to all of you who followed along as I had it shipped here from the UK back in May.
The tandem has the original (1952) Stronglight cottered cranks with TA rings. The seller actually gave me a nice supply of spare rings, but what I need ain't there...
I am running a 4-speed cyclo-benelux freewheel on the rear (with a cyclo-benelux derailleur). The freewheel is 1/8 inch... so I would like to find a final drive ring in 1/8 inch. The stronglight cranks use the traditional 5-bolt pattern, but the ring needs to have holes to which I can mount the timing ring...
The six holes for the chainring bolts to which the inner ring will be mounted are 55mm from the edge of the inner center hole of the chainring...
I hope this is all clear - if not, I can send a pic. I'm sure there are plenty of 3/32 rings out there, but I have a 1/8 chain and the 1/8 block - it would be sloppy indeed to put a 3/32 final drive ring on there just to get the project completed...
So, if anyone can help, please let me know.
I am looking for good to average condition - I am restoring the tandem with original paint, and the original components, no NOS here...
If you can help, please contact me off-list.
Thanks everyone!
Duncan Granger
Mountville, PA