and one other thing, was chatting to a couple mates about it. a few issues are, the clearance internally is very small so be careful, 2 ss may be a problem as the casing is alu and the two metals will likely create electrolysis causing rusting which is a major problem, 3 the 2 metals have different expansion qualities which could either create binding leading to potential treading or 2 it may weep when the two metals are at different heats. 4, its much cheaper to put in a fresh plug every time you re-grease it. apparently they make them that soft to ensure its the first thing that damages as it is easy to throw away and replace.
if you think it is worth proceeding after considering these issues let me know, if not im happy to just buy a couple spares and treat them as throw away pieces.
let me know your thoughts