Hi Peter,
"Freehubs" were not uncommon among top-of-the-line cyclotouring bikes in France in the 1940s. The idea was to be able to remove the wheel without wrestling with the chain - most derailleurs back then wrapped the chain around the rear wheel 3/4 of the way, so you could not "drop out" the wheel downward until after you had somehow got the chain between dropout and hub axle... Later, they solved that problem more elegantly with the chainrests brazed onto the frame. (And the advantage of being able to replace drive-side spokes on the road was solved with Maxi-Car's keyhole spoke holes, or by using huge flanges that cleared the entire freewheel, like on E. Csuka's Alex Singer tandem in our book "The Golden Age of Handbuilt Bicycles.")
Is it really a Moyne hub, or just a Moyne freewheel on another hub? There were lots of designs, starting in the 1930s - Maxi-Tank, Cyclo-Tank, Maxi-Car-Tank are the more common ones, all using a Tank/Merveille "cassette" on various hub bodies.
Are the axle threads metric? If so, it's probably a French orphan.
The Rene Herse in VBQ Vol. 3, No. 1 has a hub somewhat similar to the one you have. The article didn't show the disassembled hub, but it had Rebour drawings that showed the function. That hub used standard freewheel threads, it appears - unlike the various "-Tank" designs, which resembled modern freehubs.
A photo of the bike is at
http://www.vintagebicyclepress.com/
Outboard bearings: Most French 1930s Cyclotouring hubs had the rear right bearing all the way on the outside, and they used a freewheel with a bigger "hole" - but you were limited to 14 or 15 tooth cogs as a minimum. Still - it's not a bad idea. The "-Tank" hubs don't have the second bearing far outboard - they are more like modern (OT) Campagnolo hubs in this respect, not like Shimano freehubs. But with 4- or 5-speed and solid axles, axles bending or breaking wasn't a huge issue anyhow.
Threads or lack thereof for cogs: That one is a new one for me, too. All my Moyne hubs have screwed-on cogs, but some screw on from the front, others from the back - so there was some experimentation going on...
Jan Heine, Seattle Editor/Publisher Vintage Bicycle Quarterly c/o Il Vecchio Bicycles 140 Lakeside Ave, Ste. C Seattle WA 98122 http://www.vintagebicyclepress.com
>Among a box of parts I have acquired is a J Moyne hub that I have not
>seen before. It is a rear hub, and appears to be similar in function to
>the 1940s/50s Baylis Wiley unit hub which I am more familiar with, in
>that the freewheel is built into the hub. The main difference to the
>B-W hub is that instead of threads for sprockets, it has an octagonal
>block onto which either suitable sprockets or some form of adapter fit,
>to be held in place by a lockring. The hub can be viewed at
>http://ntlworld.photobox.co.uk/album/1571123 . Any information about
>this hub would be appreciated.
>Peter Brown, Lincolnshire, England