The stud has a specially machined top so it can not be easily replacedThe part it was screwed into was an aluminum manifold that has since been replacedObviously the hole stripped out leaving aluminum in the threadsI can't get it outThe threads are very fineI have tried a wire wheel, picking it out with small, sharp pointed tools but most of it still remainsI tried finding a tap but these are oddball threads and none of the taps I can find match.
You need to rephrase your questionIt doe snot make sense.
Practice more, knit faster.
If the part is very old it may have hand cut threadsI have seen this beforeWhat I would do is soak the part in muriatic acid for a few hoursThe acid will dissolve the aluminum but not the steel.
