A couple questions about a Dynohub
 

I just got a 1949 or 50 English roadster with 28" wheels and rod brakes. The rear hub is a 3 speed dynohub that is dated 49. The hub is only marked with the date, "Dyno 3 Three" inside a diamond and patent numbers. Here's the questions: The hub has an 18T screw on cog. I would like to install a larger cog. Is there a source for threaded 20T and 22T cogs anywhere? I know I can swap in a new style driver and use 3 spline cogs, but would like to keep it original if possible. If I do swap drivers, which one do I get? I have never seen a Dyno3 before. What cartridge is in it? It looks like a Sturmey Archer AW, but I don't know them well enough to be sure. Sorry if these questions have been answered before. I did quite a bit of research, including Sheldon Brown's site and couldn't find an answer to either. Thanks for any insight you can give.

The threaded driver will accept standard track cogs, which are available with 22 teeth. You will not need a lockring, since the hub does freewheel. The problem is getting the cog off the driver, which requires partially disassembling the hub. You can replace the threaded driver with a standard AW splined driver and use a splined 22T cog instead.

Thanks. So, does that mean the Dyno 3 is actually a Sturmey Archer AG?