DESCRIPTION: This fuze, which may be identified by the stencilling "Kz. 38" on the dome-shaped body is, included the gaine, 1 ounce in weight and 2 inches in length; the length of the body protruding from the nose of the shell is. 0.06 inch. The empty fuze is similar to the British fuze No. 250 Mk II. The fuze is of the di-rection action type, and the principal parts are, the body with adapter, striker guide, striker and hammer, arming sleeve and arming spring, stirrup spring and ferrule, three balls, igniferous detonator and gaine. (See fig. 568.)

The dome-shaped body has a flat nose and is prepared with an internal channel stepped in four diameters and screw-threaded 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 copper disk 0.006 inch thick.

The adapter is screw-threaded externally to receive the body and to screw into the shell. Internally it is screw-threaded to receive the striker guide and its upper end has a chamber 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 un-armed 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 screw-threaded 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 striker, and the lower part accommodates an igniferous detonator held bet-ween a shoulder and a plug, with central fire channel, which screw into the bottopm 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 striker head and there-by hold the striker off the detonator. Before firing, they are retained in position by the arming sleeve.

The striker ist of steel and flanged at its upper end to enable it to be engaged by the three balls and held in the safe position. A wooden hammer, shaped with a head, rests on the top of the striker and is retained in position by a copper disk, which closes 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 ingniferous detonator contains about 0.5 grain of a mixture of mercury fulminate, potassium chlorate, antimony sulphide (with, possibly, a small proportion of ground glass), followed by a thin layer of gunpowder. It the same size as the ignitory detonator in Fuze No. 250.

The gaine, approximately 1.05 inch long is a steel cylindrical body closed at its bottom end and containing 7 grains of CE/TNT (40/60) pressed extremely 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 grain of C.E. under 6 grains of fulminate of mercury. The flash hole in the top of the cap-sule is closed by a fabric disk on its undersite. The mouth of the grain is screw-threaded to enable it to be screwed on the striker guide of the fuze, and contains a leather was-her under a metal washer which fits over the detonator cap.

ACTION: This fuze is of the floating striker type and is not provided with a supporting spring; it, therefore, cannot be overemphasized that before being fired the closing disk in the nos of the fuze should be examined to see that it is not damaged or perforated, other-wise 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 upwrds by its spring and unmasks the three holes in the striker guide.

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

On impact, the hammer is forced in, driving the striker inot the detonator, which is fired and in turn set off the graine detonator and gaine which detonates the shell filling.

Figure 568 – D.A. K.Z. 38