Object Title

Display case - Sectioned fuzes by George Kent Ltd

Display case - Sectioned fuzes by George Kent Ltd

Date

1914-1918

Object Number

XX.934

Provenance

Purchased at Kent Arms Sales, 29 November 1984.

Physical Description

This group contains fuzes used by the Army, Navy and RFC. Twelve of the fuzes are base or nose fuzes for shells and bombs, while two are vent sealing tubes for gun breeches. Accompanying the fuzes is a thirteen-page typed explanation of the design, manufacture, and use of each example. Unfortunately this is unsigned, but it was obviously written by someone closely involved in the manufacturing operations of George Kent Ltd, and opens with the following paragraph:
'In the following notes I have had to trust to my memory, but as the study of the fuzes during Contract negotiations and getting them into production at Luton was part of my job and the organising of all supplies of metal, explosives and the many parts manufactured outside, was entirely my work, I have a fairly well ingrained memory of the why and how surrounding the designs.'
The writer goes on to say:
'It is necessary, when examining these sectioned fuzes, to bear in mind the conditions under which they had to function and particularly the safety devices employed for the purpose of prevented premature explosion.'
'In those days shells were fuzed as required in the field, the type of fuze used being governed by the nature of the action being fought.'
The original document is preserved in the inventory file, while a photocopy accompanies the fuzes. It is recommended that this be consulted for detailed information on each fuze. The following however is a brief list on those discussed.


(1) Fuze 80
An all-brass time and percussion fuze for the nose of a shell. A brass cylinder carrying a priming cap in the nose of the fuze was suspended over a fixed striker by a brass stirrup. Inertia at the moment of firing caused the primer carrier to overcome the resistance of the stirrup and to fall onto the striker. The ignition of the primer set off a powder train contained in galleries in two rotating rings, the burning time of this powder train being variable by adjusting the position of the lower ring. If the shell struck a solid object before the time fuze had burnt through a second primer, mounted in the base of the fuze in a carrier retained by a spring flew forward and instantly exploded the shell. The edge of the cone is calibrated to indicate the setting of the burning time of the fuze, while the base of the fuze is stamped VII, GK and /18.


(2) Fuze No. 133/1
A brass percussion anti-aircraft shell nose fuze, this employs a three-part gravitational-lock plunger arrangement which carried the priming cap. This simple mechanism was cocked on firing, exposing the cap to a four-pronged striker, the plunger and cap moving forward into contact with the striker when the shell struck a solid object. The nose of the fuse is stamped GK No. 1331/18.


(3)
A large percussion shell nose fuze. Of simple construction, this consists of a grey-coated brass cone above a stout threaded portion, the centre of which has a cylindrical chamber for a large charge of tetryl. In the nose of the fuze is a long steel striker, with a large aluminium-filled head. To prevent the striker moving back into the primer there is a heavy iron washer, in two parts, held in place by a coil of brass tape, the outer end of which is fitted with a small kidney-shaped weight. The striker head assembly is covered by a heavy iron cap screwed onto the nose, this cap being discarded before the shell was fired. As the shell spun on firing the brass tape unwound and the two-part spacer fell away. A vacuum formed beneath the striker head held the striker away from the primer until the shell struck a solid object. This sensitive form of percussion ignition made this fuze particularly suitable for use against light defences; barbed wire for example.


(4) No 18 Fuze-Admiralty
A simple all-brass percussion fuze for a shell nose, consisting of a tubular casing, the outside of which is cut with a long tapered thread for rapid installation into the shell. The mechanism is simply a cylindrical iron plunger fitted with a striker, held above a priming cap cavity by a steel cross-pin. On striking a solid object the cross-pin was sheared and the striker driven back into the primer. The striker, covered by a brass disc, is protected by a brass cap attached by a bayonet fitting and secured by a copper pin and twine becket. The cap is stamped No.18. The edge of the upper end of the fuze body is stamped with +5, and faintly with GK, P, PK, and 1/16.


(5) Probably an Admiralty fuze, possibly No.17. This is a time and percussion shell nose fuze, similar in outline to (1) above, but of aluminium except for the powder train rings and internal components. This lighter weight construction was intended for use in long-range shells. The principle of operation is similar to that of (1), but the internal design differs. Instead of a priming cap suspended above a striker this fuze's time ignition is begun by a spring-retained striker being impelled back into a primer seated to one side of the core of the fuze, thus setting off the powder train. The percussion primer, seated in a large cylindrical base block secured by a helical spring, would be thrown forward on impact onto a fixed striker. Accidental explosion of this primer was prevented by a copper pin lying across the top of the base block. The edge of the cone is calibrated, and the nose cap is stamped No. 84, I, GK, /17.
(6) Fuze No.65A-RFC supply. For anti-aircraft service. A time and percussion fuze of all-brass construction consisting of a barrel-shaped body composed of a cylindrical base-ring section, above which are a serrated ring, a graduated ring, a domed cap, and a hexagonal cap nut. The stout thread beneath the base ring is tapered. The timing system in this fuze is similar to those of fuzes (1) and (5) above; the time of burning of the powder train having been set mechanically as the shell passed on a belt to the breech of the gun. The striker, mounted on a brass cylinder, is suspended by a copper cross-pin above a priming cap. On firing the shell the cross-pin was sheared, the striker then falling onto the primer. The percussion striker, located on a cylindrical block in the base of the fuze, is equipped with two centrifugally-operated locking devices to prevent accidental explosion; i). sliding cross-bar weighted at one end opposite a light spring, the weight overcoming the spring as the shell rotated, drawing the end of the bar out of its engagement in a hole in the casing. ii) a small steel ball, placed on the upper end of the striker block thus preventing the block from moving forward until a cylindrical locking piece suspended by a shearing-pin, fell into a cavity as the pin sheared on firing, the ball flying outward as the shell spun and falling into the same cavity, leaving the striker block free to move forward on striking any solid object. The complexity of this fuze apparently made it unpopular. The hexagonal cap nut is stamped (N) O 65A, the base ring is stamped P, /17,& G(K).


(7) Mark 121 Fuze. Anti-aircraft, time only.
This is a time only fuze for a shell nose, of all-brass costruction and of small size. It lacks the firing needle striker and its retaining stirrup spring. It operates in much the same way as other time fuzes. The nose cap is calibrated. A serrated ring set the time of the fuze as the shell passed over a belt on its way to the breech of the gun.
(8) Admiralty supply. Base fuze for armour-piercing shells.
A large fuze of all-brass construction. The fuze was set or 'cocked' on firing by the blast from the charge forcing a copper locking-rod forward, allowing a weighted locking-bar to be thrown out of engagement by centrifugal force as the shell travelled down the gun barrel. A second lock (a small spring-loaded brass cylinder and a small steel ball). was also disengaged by centrifugal force. As the shell struck a solid object the brass core of the fuze carrying the priming pellet and now unlocked, was thrown forward onto a striker. The flash from the primer ignited a powder train whose brief burning time gave the shell enough time to enter the target before the main charge was ignited. The base of this fuze is stamped No.12 F IX GK, and SPEC(IA)L.


(9) Fuze 44 War Office (Krupp design).
A percussion nose fuze for a shell, this was the first type of fuze to be manufactured by George Kent Ltd. Of all-brass construction this fuze had a long tapered thread for rapid insertion into a shell. The striker was mounted on the underside of a copper diaphragm in the nose of the fuze, directly pver a priming pellet. Impact on a solid object simply drove the striker back into the primer. The only safety feature is a centrifugally operated shutter-plate which on firing opened a fire channel between the primer and tetryl charge. The nose of the fuze was protected by a brass cap, to which was attached, by a becket, a copper pin which secured the shutter in the safe position. The cap and pin were thus removed together before firing. The top of the cap is stamped (faintly) GK over two horizontal lines, and the edge of the nose of the fuze is stamped GK 1915.


(10) No.1 Aerial bomb fuze.
This percussion fuze, of all-brass construction, was fitted into the nose of bombs dropped by hand from aircraft. The centre striker is the sharpened end of a screw thread forming the spindle of a propellor. Accidental discharge was prevented by a heavy brass spacer disc retained by a spring clip and by a vertical rough-turned steel pin passing through this spacer, which prevented the propellor turning. Before dropping the bomb a copper pin was removed from the spacer, which was then, together with the steel pin, discarded. As the bomb fell nose first the air current drove the propellor, which brought the striker close to, but not touching, the priming pellet. This action gave time for the bomb to fall some distance from the aircraft before it became armed. As the bomb struck a solid object the tube carrying the striker sheared its supporting pins, allowing the striker to impact upon the primer. The plate beneath the propellor is stamped No.1, GK, and 3/16.


(11) No.49 Fuze, Admiralty.
A percussion fuze of simple design, of largely brass construction, which utilised a similar safety feature to that of No.(3) above: Namely that as the shell was fired the striker was prevented from flying back under inertia into the primer by a two-piece spacer under the head ofthe striker, held in place by a weighted brass tape. As in (3) the tape unwound as the shell spun, and the spacer fell away, leaving the striker free to move back into the primer when a solid object was encountered. As a fuze intended for long range shells it has a striker carrier of aluminium. The tapered thread allowed rapid insertion into a shell, and a brass cap protected the striker head until being removed before the shell was loaded. The cap is secured by a copper pin and becket. The edge of the fuze casing, beneath the striker head, is stamped GA in an oval, a broad arrow, N(?), No.49 T (or I), GK and /17. The top of the brass cap is simply stamped No.49.


(12) Percussion Fuze possibly No.60, Army Contract.
A heavy shell-nose fuze of all-brass construction, of simple design. This fuze is in the 'fired' position. On firing a small brass rod supporting a locking pin was forced back against spring pressure. This action withdrew the locking pin and allowed a laterally-placed locking peg to be thrown outwards by centrifugal force, thereby leaving a brass cylinder, with a priming pellet mounted on its forward end, free to fly forward onto a striker when a solid object was encountered. The base of this fuze has a large internally-threaded skirt, which was originally for the attachment of a 'gaine', a tetryl-filled steel tube about six inches long intended to cause greater fragmentation of the shell. The nose cap of the fuze is stamped with a broad arrow, while the sides of the case are stamped GK, ZA over 91, 7-16, E over 2, a broad arrow and 525.


(13) Percussion Vent-Sealing Tube, Admiralty supply.
This resembles a rifle cartridge case and operated in much the same way, having a centre-fire striker above a priming pellet. The main body of the tube, however, was originally filled with tetryl, which better aided the ignition of the main charge of the heavy naval guns for which these tubes were intended. This tube is sectioned through its centre-line, the markings on the half of the base remaining being a small broad arrow in a circle, VI and GK.


(13a) Electrical Vent-Sealing Tube, Admiralty supply.
Similar in form to (13) above this too resembles a rifle cartridge, but its tetryl charge was ignited by the heating electrically of a fine platinum wire in the centre of the tube to white heat. A white metal plug in the base of the tube was the external electrical contact.
These fuzes are contained in a good quality polished walnut case lined with blue velvet, each fuze, with the exception of the vent-sealing tubes, having an individually shaped recess. The centre of the outside of the lid has a white metal disc attached by three screws and engraved GEORGE KENT LTD 1914-1918.

Associations

Places England