U.S. Artillery fuze threads

An earlier thread indicated that most U.S. Army artillery fuzes were threaded 2 inch x 12 TPI.

I have a few projectiles that had been mistreated and the noses slightly messed up so fuzes will not screw in. Any suggestions other than grind out the damaged threaded areas? Are 2" x 12 TPI taps available at reasonable prices to freshen up the threads?



What I have done is use a Moto tool or other high speed hand grinder and a small (1/2") diameter “V” shaped grinding wheel to freshen up the thread that has been damaged. Only takes a few minutes and is certainly far cheaper than buying a tap. USN and USA fuzes are found in more than one size and having to buy two or more taps would be cost prohibitive.


OTC (Otawanda Tool Company) makes a large thread clean up tool (thread chaser), that’s shaped like the letter “F”. One “jaw” rides aganst the piece, the other holds a cutter to clean up the threads. I picked up the one I use at work at my local Grainger’s outlet.
grainger.com/Grainger/OTC-Th … Pid=search
Note that it comes with the inserts for a number of “inch” threads, and that you can pick up a set of metric inserts also (if needed)