(Fig. 8)

This fuze, which may be identified by the stencilling "Kz 38" on the dome-shaped body is, including the gaine, 1 oz. in weight and 2 inches in length, the length of the body pro-truding from the nose to the shell is 0.6 inch. The empty fuze is similar to the British fuze No. 250, Mk. II. The fuze is of the direct action type, and the principal parts are, the body with adapter, striker guide, needle and hammer, arming sleeve and arming spring, stirrup spring and ferrule, three balls, igniferous detonator and gaine.

The dome-shaped body has a flat nose and is prepared with an internal channel stepped in four diameters and screwthreaded internally at its base to receive an adapter. The smaller diameter at the forward end houses the head of a wooden hammer, and below it is a chamber to accommodate the arming sleeve after firing, and a second step which forms a shoulder and bearing surface for the upper end of the ferrule. The channel is clo-sed at its front end by a copper disc 0.006 inch thick.

The adapter is screwthreaded externally to receive the body and to screw into the shell. Internally it is screwthreaded to receive the striker guide and its upper end has a cham-ber to receive an arming sleeve and arming spring which surround the upper end of the striker guide. The sleeve and spring are retained in the unarmed position by a stirrup spring and ferrule. A pin through the side of the adapter prevents the ferrule from turn-ing.

The striker guide is screwthreaded externally to suit the adapter and to receive a gaine body, and has a central channel. The upper part of the channel forms a guide for the hammer and needle, and the lower part accommodate an igniferous detonator held bet-ween a shoulder and a plug, with central fire channel, which screws into the bottom of the channel. Three radial holes are bored in the upper part of the channel and partially accommodate three balls which rest against the underside of the needle head and there-by hold the needle of the detonator. Before firing, they are retained in position by the arming sleeve.

The needle is of steel and flanged at its upper end to enable it to be engaged by the three balls and held in the safety position. A wooden hammer, shaped with a head, rests on the top of the striker and is retained in position by a copper disc, which closed the nose of the fuze.

The arming sleeve is cylindrical and fits around the striker guide to retain the balls. It is flanged at its upper end to form a seating for the arming spring and has a curved peri-phery to suit the stirrup spring.

The stirrup spring is cylindrical, its lower edge has a number of external projections which fit under the ferrule, and its upper edge has a number of internal projections which fit over the arming sleeve and keep the arming spring under compression.

The ferrule is cylindrical, its upper end engages a shoulder in the body and its lower end the stirrup spring. A pin engages a slot cut vertically in one side of the ferrule and pre-vents its rotary movement in the fuze.

The igniferous detonator contains about 0.5 grains of a mixture of mercury fulminate, po-tassium chlorate, antimony sulphide (with, possibly, a small proportion of ground glass), followed by a thin layer of gunpowder. It is the same size as the ignitory detonator in Fuze No. 250.

The gaine approximately 1.05 inches long, is a steel cylindrical body closed at its bottom end and containing 7 grains of CE/TNT (40/60) pressed extremly hard into the base with a thin layer of the same composition in the form of loose crystals on top. Above this is an inverted cup-shaped capsule containing a detonator composition consisting of 0.46 grains of C.E. under 6 grains of fulminate of mercury. The flash hole in the top of the capsule is closed by a fabric disc on its underside. The mouth of the gaine is screw-threaded to enable it to be screwed on the striker guide of the fuze, and contains a leather washer under a metal washer which fits over the detonator cap.

This fuze is of the floating needle type and is not provided with a supporting spring; it, therefore, cannot be over-emphasized that before being fired the closing disc in the nose of the fuze should be examined to see that it is not damaged or perforated, otherwise the round may be fired prematurely by air pressure acting directly on the hammer.

On firing, the ferrule sets back and takes the stirrup spring with it, thereby releasing the arming sleeve, which is forced upwards by its spring and unmasks the three holes in the striker guide.

During flight, the needle and hammer tend to creep forward owing to deceleration, the three balls are released and fly outwards under centrifugal action and so release the needle.

On impact, the hammer is forced in driving the needle into the detonator, which is fired and in turn sets off the gaine detonator and gaine which detonates the shell filling.

Fig. 8