EMPLOYMENT: Used in shells for heavy guns the ammunition for which is often of Naval design. (See fig. 603.)

CONSTRUCTION: The fuze is an igniferous base fuze of the graze type with a delay ac-tion.

The body is of steel, brass plated, and closed at the forward end by a screwed in brass head with a central cavity and flash hole sealed with a brass disk and varnish. The body is screw-threaded externally with a right-handed thread for insertion into the shell and recessed internally to take the grazed mechanism.

The brass head is internally screw-threaded to take a brass plug which holds a screwed brass delay unit at its forward end.

The striker is of steel and is secured by a steel plug which screws into the striker holder. The point of the striker protrudes into the top of the graze pellet. The recess in the fuze body houses a steel platform which carries five centrifugal segments overlapping the top of the brass graze pellet. The segments are encircled by an expanding ring of phosphor bronze which retains them in the overlapping position and thus prevents forward move-ment of the graze pellet.

The brass graze pellet, which is closed at the base by a screwed in steel plug, houses a detonator holder resting on a fibre washer. The detonator consists of a copper shell clo-sed at the top by a copper disk at the bottom by a copper disk with a square hole in the center covered by a paper disk. The filling consists of 1.2 grains of detonating composi-tion over 13 grains of gunpowder. The composition is made up of mercury fulminate 21.3 percent, potassium chlorate 44.0 percent, antimony suphide, 34.0 percent and grit 0.7 percent.

The delay unit is in the form of a brass plug with a central flash hole in the base and a recess filled with 0.8 grain of pressed powder. An eccentric flash hole leads to a larger recess in the forward end of the unit which contains 1.2 grains of pressed gunpowder. Above the delay unit is a filling of 23 grains of pressed gunpowder contained in a recess in the brass head of the fuze.

OPERATION: Centrifugal force set up by the spin of the projectile in flight causes the spring ring to expand and permit the segments to rotate on their pivots thus freeing the graze pellet which, as there is no creep spring, tends to creep forward toward the stri-ker. The detonator is pierced immediately on graze or impact and the flash produced passes through the flash holes in the striker holder to the delay unit.

REMARKS: The Bd.Z. C/36 fuze is similar to Bd.Z. C/38, except that it is of smaller gage. It is constructed largerly of steel and is fitted with brass segments. It operates with a delay of 0.03 second. The fuze is used in the 28-cm range of shell.

The Bd.Z. 40 K base fuze is also similar to Bd.Z. C/38 except that it has a larger gage and is fitted with a creep spring. The fuze is constructed largely of steel and the seg-ments are of aluminum.

Figure 603 – Bd.Z. C/38