Mk 34 Mods 0 and 1

Projectiles used in

Over-all length, inches

Diameter, inch

Threaded length, inch

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Material

Description: This fuze consists of one housing containing the firing pin and rotor units. Above the firing pin is a plastic firing-pin extension. The firing pin is held up by two detents, which are held in place by a circular copper band surrounding them and acting as a spring. Beneath the firing pin is the rotor, with the detonator at an angle of about 55 degrees from the axis of the fuze. The rotor is held in the unarmed position by a set-back block connected by a copper shear wire. In this position, the detonator is out of line with both the firing pin and the booster.

Operation: On set-back, the set-back, the set-back block moves back, breaking the shear wire that has been holding it to the rotor. Centrifugal force causes the firing-pin detents to move outward and to turn the rotor so that the detonator is aligned with the firing pin. The rotor is held in this position by centrifugal force. On impact, the nose of the fuze is crushed and the firing pin extension drives the firing pin into the detonator.

Remarks: The Point Detonating Fuze Mk 34 Mod 1 differs in that the firing pin detents are "hour-glass" detents. On set-back, the firing pin will back against the detents, and (because of their shape) they will be held in place until the firing pin moves forward again under the influence of creep.

The plastic firing-pin extension is a safety device. In the event that the round is dropped, the plastic extension will shatter, where a one-piece metal firing pin might force its way past the firing-pin detents and initiate the fuze.

Figure 85. Point Detonating Fuze Mk 34 Mod 1