well I just ordered the 46 tooth blank sprocket from cycletreads.co.nz for the princely sum of 44nzd, I'll tell the engineer how you've done it muscrat and hopefully be able to post pics of the finished job in due course.
I guess depending on your location it might be cheaper to buy a new hub complete with sprocket for the crinkle hub wheels but in my case where the sprocket/drum/hub is effectively one piece (riveted together) refurbing with a new sprocket is pretty much the only option anyway.
Whilst this is an A10 thread here is a pic of the b31 hub - basically a cheaper version of the A10 hub but with 520 size sprocket, I did consider trying to adapt the plunger wheel onto the rigid b31 but whilst it is the same width the sprocket and rim alignment is wrong for the b31, and it would also need a custom axle made up.
