The cylinder pivot is made from a silver steel rod of 4mm diameter.
It should be machined to ensure that there is a square shoulder at the root of the 5BA thread. This helps the pin to pull square to the cylinder port face when tightened.
A piece of 4mm silver steel should be cut over-long by a couple of mm's and the ends squared off in the lathe.
Next a sharp pointed tool can be used to turn a section of the shaft to 2.7mm diameter. This reduced section can be longer at this stage to aid the threading process.
To cut the thread, the tailstock can be used to keep the die square to the work and apply a light push force. The tool post being positioned to stop the die holder rotating and then the chuck can be turned by hand to cut the thread up to the shoulder.
To cut a square edge at the root of the thread, a very narrow, sharp tool should be used as shown.
Then the completed thread can then be reduced to final length using the cylinder tapped hole as a guide.
Finally the M4 thread must be added to the other end of the pin by reversing the part in the chuck and using the same threading technique.
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