sear screw and rear sight screw tap size

[jim simos]

does anyone know the sear screw thread size and know were I can find a tap. I bought a musket with a broken screw in the lock and it will not drill out. I also have a broken screw in the rear sight/barrel spanner screw and I believe I read somewhere that was A 8-32 tap size , is this correct.
Thanks
Jim oops forgot ! the musket is a 1862 original Springfield 3 band

[mikea]

Better specify exactly what kind/type of musket you have, who made it, etc. Repro's don't necessarily use the same thread sizes as originals.

[R. McAuley 3014V]

does anyone know the sear screw thread size and know were I can find a tap. I bought a musket with a broken screw in the lock and it will not drill out. I also have a broken screw in the rear sight/barrel spanner screw and I believe I read somewhere that was A 8-32 tap size , is this correct.
Thanks
Jim oops forgot ! the musket is a 1862 original Springfield 3 band
S&S Firearms carries a "musket and trapdoor lockplate tap" (SA183) for cutting new or restoring original threads. They also sell a 1" die for recutting or restoring the threads for lock screws and ramrod tips. Rear sight screw is very short, and only has about four to five threads, so if you can extract the screw without injuring the threads, you may not need a tap to refreshen the threads. Most all of the thread count used on the U.S. Springfield rifled musket were 26 tpi (threads per inch), which does not match any modern thread standards.

[jim simos]

Thanks for your reply , I called S&S but they only carry the tap for the lockplate screw but none for the sear,bridle screws .