Components of explosive train: Primer, delay train, gaine, and booster. Relay incorpora-ted in gaine.

Fuzes likely to be found with: A-8 (a).

Delay times: 3.5 seconds, or an alternative setting of approximately 25 seconds.

Description: The fuze consists of a vane assembly, hub housing, striker housing, lower fuze body and sealing ring.

The arming vane assembly consists of three black vanes attached to a hub. The hub is retained in a cylindrical housing by two retaining pins which permit the hub to rotate. There is a locating pin on the inside of the gub which fits in a longitudinal keyway in the arming spindle. The hub housing is threaded internally at its lower end to screw onto the striker housing.

The striker housing has a threaded hole in its center. The arming spindle screws through this hole and into the striker. A locating pin on the inside of the housing fits into a longi-tudinal groove on the striker and prevents it from rotating. The striker is separated from the primer by a spring.

The lower fuze body contains the primer and delay train. The primer is carried in a threaded plug which screws into a hole in the center of the body. The flash lead in from the primer goes through the body to the delay train. This consists of a ring having a pressed brown powder train in a groove. The ring is a friction fit on the body and fits against a flange on the lower fuze body. A beleved washer fit-ted between the delay ring and the striker housing maintains a constant tension on the ring. The delay train burns around to a lead out that goes down diagonally to a relay of black powder on top of the gaine.

The sealing ring is a large knurled brass ring. The lower fuze body fits into the ring so that its shoulder bears against a flange on the base of the ring. A rubber gasket on the out-side of the ring seals this connection. The ring extends up slightly beyond the shoul-der of the striker housing. A brass washer with a rubber gasket glued to it threads into the top of the ring and screws down so that the gasket bears on the shoulder of the striker housing.

Operation: Arming vanes rotate causing the arming spindle to unscrew from the striker. On impact the striker compresses the spring and hits the primer. The flash ignites the delay train which ignites the relay which in turn sets off the gaine.

Figure 106 – B-7 (a) Bomb Fuze.