[HAM] BC tremulant oil threads (again)

[Hugh]

Maybe a picture will jog someone's memory. Here's the tremulant drive 
case opened up showing the brass tube coming in the top and the brass 
fitting with a hole near the bottom left. Would anyone know how the 
tremulant oil threads (if there are any) are routed? There's no 
groove around the motor bearing to retain the thread, so it's a bit 
of a mystery. If anybody out there has a BC or a D, I'd appreciate it 
if they could have a look if a thread goes down that tube.

http://members.shaw.ca/brooo/tremulant.jpg

Thanks,
Hugh