Lucas distributor cap repair 1929 7Hp DS2 1495/ 529

[Dhbangham]

I have the above distributor on my Long 4 7hp and noticed the other day that the spring on the top of the rotor cap was not really connecting with the center bush of the distributor cap. It appeared that over the last 90 years it had worn down. This distributor cap does not have a sprung loaded graphite slug that can easily be replaced, like more recent distributors. On investigation it appeared to have a white metal slug (cylinder) that is soldered to a brass mount that is in turn attached to the center of the cap. See image attached.
To rebuild this part of the cap I was able to mount the cap on my myford lathe (Using 3 jaw chuck on inside of cap, very carefully) Then using a 3.85mm slot drill in the tail stock, machine out the original rivet head, this allowed me to push out the rest of the brass mount.
After measuring the original. I turned up a replacement mount in brass. tThe inital problem was how to create a long exposed slug of white metal that was securly attached to the brass holder. The answer was to incorporate an extra long cup on the holder with a 7mm internal diameter then fill that cup with white metal (using bakers fluid flux) When solid, I was then able to turn away the excess length of brass cup leaving the exposed white metal protuding from the brass holder, where it was securely soldered in place. Finally I used a 9ba screw and brass washer to secure the new holder in the cap.