An interesting fuze. No idea what it’s for. It’s stamped “DELAY” next to the recessed screw.
No. It’s me with the bad eyesight (for real.) But it is stamped “DELAY” right beneath the screw-like actuator (center of photo.)
The screw head on the side is used to select either “Delay” or “Super Quick (SA)” function.
" The M48 series point detonating fuzes offer selection between superquick or 0.05 second delay action, and are used primarily to detonate Smoke, WP ammunition in calibers 75mm, 90mm and 4.2-inch.
The M48 series fuzes have a PD head assembly containing a firing pin held in position by a firing pin support which prevents initiation of Detonator M24 until impact. The fuze body contains an M1 delay plunger assembly and an interrupter assembly with a setting sleeve which provides a means of setting or selecting fuze PD (Super Quick Action) or delay functioning The delay plunger assembly includes a firing pin and Delay Element M2. The delay element includes Primer M54, a black powder delay charge and Relay M7. The delay plunger assembly of the M48A2 fuze comes with delay times of 0.05 seconds or 0.15 seconds, the time delay being stamped on the fuze body. The head assembly is attached to the body by means of the flash tube which also positions the fuze windshield or ogive. The ogive is a thin-walled steel stamping utilized to provide an aerodynamic shape to the fuze."
(Info from the excellent heavy ordnance site http://Bulletpicker.com)
Note that while primarily used in the 75mm, 90mm and 4.2 inch ammunition, these use standard 2 inch x 12 threads per inch and will fit on nearly all modern U.S. Army projectiles.
Thanks for your help. I knew there’d be somebody out there who’d know exactly what some of these things are…