Over-all length: 2 7/16 inches.

Maximum diameter: 2 5/8 inches.

Threaded length: 1/2 inch.

Number of threads: 4, right-hand.

Construction: This fuze is made of brass. A central spindle and base section are made in one piece. Two powder time rings (the upper fixed, the lower movable) are fitted around the spindle and held in place by a nose cap, which threads onto the top of the spindle. The time-ring primer is housed in the nose cap and before firing is supported by a safety pin which passes through it and the nose cap. The primer is also supported by an arming sleeve. A partition in the hollow spindle has a firing pin on both sides. A second movable primer (impact primer) is housed in the base of the spindle. It is held in place by two centrifugal detents and separated from the firing pin by a coiled spring. A base plate threads into the base sec-tion and contains a black-powder magazine. The movable time ring graduated from 0 to 22 seconds in increments of 1/5 second.

Operation: Before firing, the safety pin is removed and the time ring set. On set-back the time ring primer moves down onto the firing pin. The flash from the primer passes through a flash channel to the upper time ring. The powder train leads through the time rings down to the black powder magazine.

Centrifugal force causes the detents to move out, freeing the impact primer, and, if the projectile hits before the time setting has elapsed, the primer carrier moves against the spring onto the firing pin. The flash from the primer sets off the black-powder magazine.

Figure 332 – Type 3d-year Combination Powder Time and Impact Fuze.