Aveling piston valve bobbins 4 nhp engine
 

I have two used cast iron piston valve bobbins from a 4 nhp tractor, which I think are the same as those from a 'C' or 'D' type 8 ton roller 1920 to 1929. O.D. 2 3/4", machined length 1 3/8". Available free of charge (but plus postage) to anyone interested, PM including your email contact details for more information. Sandy Ross