|The No.69 was shipped without the detonator which was inserted just before use.
A small screw plug in the base provided access to a central tube where the
detonator was placed. A rubber stub on the plug held the detonator secure, directly under the fuze.
There is a filling plug on the side, for factory use.
These were assembled with various glues and thread sealants. Examples are often not completely strippable.
The painted markings did not adhere well to the Bakelite, the reason many examples found are unmarked.
Fuze components: lead alloy ball; striker w/creep spring; pellet w/primer; arming tape w/bolt.
The screw cover is removed, and the thumb placed over the safety tape weight to hold it in place. When the grenade is thrown, the weighted lanyard unwinds and withdraws the safety bolt. The striker is then supported only by a light creep spring. Impact from any direction would cause the striker and pellet to be compressed, firing the sensitive primer.
The explosive flash is directed out the bottom and into the detonator below.
The primer compound is very sensitive to friction or pressure. The split firing pin tip was to ensure ignition of the primer.
There are three principal variations of the No.247 Fuze:
Marks I, II and 3. These differ in manufacturing details and materials.
The most readily observable difference between the Mk.I and Mk.II, is the striker. At far left is the Mk.II style, which has a single point and is slightly shorter than the Mk.I which has a split, two-prong tip.
(These are from No.77 WP grenades.)