I solved a similar problem in my Russian 8R clone using emery compound generally used to grind 4 stroke valve. Put a little bit of compound on the cone tip of the spindle, then gently screw the spindle in the valve body putting attention to center it correctly to avoid grinding compound to go on the thread, then close-open gently 50 times. Unscrew the spindle and flush thoroughly the whole valve inside and the spindle and reassemble with graphite pack and nut. It should seal correctly.
Might just try a piece of steel rod, drill rod or heavy music wire and grind a matching cone and go with that after trying the bluing to see what is wrong. Just wanted to make it a bit more precision but I could probably find a close enough size rod and just go with that. Probably need to disassemble the entire burner so I can clean the grinding compound out when done.
Hmm, using the spindle is a thought too. Sort of bed one into the other. Being brass it should not take much. Great ideas !
