[Amps] YC156 fitting screws

[Neil Carr G0JHC]

I am  trying to get hold of some screws for the YC156 tube,
 the 4 cathode and the 1 filament screw.
 
Anything that isn't metric is hard to find these days over here. 
 
I have tried all the local Hams "non metric" screw junk boxes to no avail.
 
Anyone know the thread?  Or even have some?
 
They are different to the 4 on the grid ring. 
 
Happy to pay for them +shipping.
 
Help appreciated.
 
73 Neil G0JHC.