Here is the finished bolt reinstalled in the manifold. It's loose enough to turn easily by hand at this point. Another solution from the VCCA site: A mate of mine had a 1938 Business Coupe that came from New Zealand,and it had a pronounced exhaust leak from between the heat control valve shaft and the exhaust manifold. After taking off the manifold,we found the valve plate itself was in real good order,we just had to figure out how to eliminate the leak. After marking the position of the plate in relation to the pin that retains the bi-metallic spring,I drilled out the spot welds holding the plate to the shaft.The shaft & the manifold were both badly worn,so I set the manifold up on the milling machine table,and put a cutter through that was 7/16" in diameter. I then made 2 cast iron bushes as it would expand and contract at the same rate as the manifold.A new shaft was made out of high tensile high temperature stainless steel.The shaft & valve plate were then "timed" to the pin for the bi-metallic spring,and a couple of spots with the mig had the valve plate fixed to the shaft securely. I then hooked up the bi-metallic spring and checked to make sure it hold the plate in the "on" position when the engine was cold,and used a hot air gun to heat the spring up,and watched to make sure it gradually opened up as it heated up,which it did. Then I liberally applied a chain & wire rope spray lube that contained a lot of graphite & moly-disulphide anti seize compounds,and problem solved. No more exhaust leak,and a working heat control valve.

Trust Series 500 is versatile and has more than adequate capacity and safety for all practical hand cutting jobs. It is designed for usewith Dissolved Acetylene or fuel gases with appropriate nozzle and also capable of cutting mild steel upto a thickness of 300mm and cast upto 75mm. The body and head of the cutting blowpipes are made from forged quality brass and precision machined for trouble free performance. Applications: MS CUTTING, CAST IRON CUTTING, SAMPLE CUTTING Advantages: Improved design of the injector ensures the optimum flashback resistance and ideal Location of mixer prevents popouts and backfires. The PTFE control valves provide fine control of flame while proteching against unintended flame fluctuation. The colour code knobs (Forged Aluminium) are provided for safe operation. Supplied with 1 No. of Gas Cutting Copper Nozzle and 1 No. Spare Check Nut for Nozzle as a package. Conforms to IS, DIN, BS & other standards. Optional : 2 Nos. Fire Preventors (Flashback Arrestor)