US Civil War cannon ball fuze

looking for the dimensions facts for a US Civil War water cap fuze, i.e… what are the threads per inches or mm, i do have one and it looks as if it is 1.5mm pitch. just need to confirm what i think is correct. i want to run a tap thru the brass bushing in the cannon ball. would this be a standard tap or do i have to make one ? if i have to make one what should i make the tap dimensions to. so i can run it thru the bushing . i want to be sure i do not retread to the wrong thread pitch. joe gatz