The history of roller chains seems to be a gradual narrowing, I'm sure driven by improved steel and manufacturing. The 1898 Davis triplet I referred to yesterday had 1" x 1/4" block chain.
Later (certainly between WW I and WW II, up into the 60s in some cases, 1" x 3/16" was all but standard for track machines. It came in two flavors: block and roller. The roller chain is several ounces heavier, and clunkier looking, but more available than the block chain. Roller chain looks like modern 1/2" chain, except with two rollers and a space, two rollers and a space,... Block chain uses (surprise) a shaped block in place of the double rollers. Looked at closely, my Wipperman blocks are three stamped plates pressed together. They seem to have been machine-ground or cut to the final shape. I know of no advantage of 1" chain over 1/2" chain, and one disadvantage: only half as many gearing options, since the cogs have only half the number of teeth.
1/8" chain is predominantly single-cog, but was used for up to 4 fw. Some 60s derailleurs were still wide enough for either 1/8" or 3/32" chain. Somewhere I have a length of chain that is half-way between the two widths, and seemed to work with 1/8" CW and 5-speed FW. Clearly a bike-boom specialty item!
hope this helps, and I won't mention that OT 9- and 10-speed units are 5/64", I'm told...
harvey sachs mcLean va
++++++++++++++++++++++ Fraser Cunningham wrote that he had a 1 inch x 3/16 block chain and was looking for a chain ring to match. Prior to this I had assumed that all single speed chains were 1/8 wide due to the supposed extra strength.Although it is hard to imagine that climbing some of the hills in The Tour don't stress a chain just as much,just in a different way.None the less I am interested in the fact that track chains in both 1 inch and 1/2 inch, block or otherwise may vary in width.Can anyone enlighten me on this topic.I would also add that until recently I thought all 1 inch pitch chains were block chains.Thanks to this list I now know differently Geoff Duke in wintery Melbourne Australia