Mk.11 helmets had two Mk's of liner Mk.1 and 11. The MK.1 liner has a oval crown pad and sponge buffers the same liner as used on the MK.1* helmet and the MK.11 liner Introduced in June 1939 has a cruciform style crown pad and moldered rubber buffers. The helmet shown has a Mk.11 liner dated 1940. An example of the Mk.1 liner can be seen in the third picture.

The first picture shows all three marks of liner securing nuts and bolts used in WW11 from left to right MK.1 introduced in January 1938, MK.11 with simmonds elastic stop nut introduced march 1940 and the MK111 three with a reduced head size as a economy measure introduced in 1942.

With the introduction of the MK.11 chin strap which had smaller end loops than the MK.1 chin strap a new chin strap lug was needed, the MK.11 chin strap lug was introduced in June 1937 [see the second picture] followed by the MK111 chin strap lug introduced early 1939 as a cheaper and quicker to make alternative to the MK.11[see third picture].

There were 4 main types of chin straps used with the mk.11 helmets. They are mk.11, mk.11a, mk.111,and mk.111a. The mk.11 chin strap is the one shown on this helmet the mk.11a is the same as the mk.11 except magnetic steel springs were used instead of non magnetic. The non magnetic ones were needed for front line use.The mk.11a chin straps were used on the mk.11 number 2 helmets for civil defence. To tell them apart the mk.11a's were marked with a letter m or a * in black ink or white paint. In march 1941 the mk.111 was introduced it is made of 25.5mm wide elasticised webbing and attached to the helmet at one end by a brass loop at the other end is a tongueless buckle for adjustment and attachment to the other chin strap lug. [See MK.111 helmet for an example of the MK.111 chin strap.] The mk.111a is similar to the mk.111 except it has a 254mm section of non elasticated webbing connected by chrome plated loops positioned in the centre these were made in relativley small numbers and were designed as a war economy measure.

The liners maker is FFL dated 1943 which is British So Its had a replacement liner at some point Possibly when or if it was used by British, Australian or free French forces in the north African campaign. The three holes in the rim are for attaching a neck guard to protect the back of the neck from the sun although there is no evidence that this was ever the used.

In 1924 Mr O Larsen registered a steel sanitary pail manufacturing company called the Transvaal Steel Pressing Syndicate, Limited (TSP).
Later the company produced milk cans and other heavy hollowware. In 1937, a public company, the Amalgamated Steel Pressing Company Limited Was formed and took over the entire share capital of the Transvaal Steel Pressing Syndicate, Limited. At the outbreak of the Second World War, the TSP was well established to tackle the many calls made on the firm.
In January 1939, the managing director Mr O Larsen visited a number of similar factories in Europe and made preparations in the event of War breaking out. For instance he ordered dies, tools and some steel plate for the manufacture of the British Mk 1* / Mk 2 steel helmets.
On his return he had to convince his Board of Directors as to his unexpected / unnecessary expenditure.
The ordered consignments only arrived after the start of the war and thanks to Mr Larsen’s foresight, steel helmet production in the Union Of South Africa commenced in about April / May 1940. There were, however many difficulties and suppliers of raw materials had to be found.
The Iron and Steel Corporation (ISCOR) a newly formed state company, succeeded in record time in producing the right quality of Bullet-proof steel (manganese steel).
We presume these were to British specifications which called for 12% manganese steel rolled into Sheets of twenty gauge - that is .036 inch / 0.9441mm thick. Although quite thin, this alloy was able to resist the penetration pistol Bullet of 230 grains travelling a velocity of 183m/s. This bullet would produce a deep indentation in the helmet but No penetration. The first three-quarter million helmets were made from ISCOR material.
A number of these helmets were shipped to Great Britain for use By fire fighting and A.R.P Services during the blitz on London. The weekly production of helmets was between 10 000 and 12 000. Later, In order that ISCOR could concentrate on other goods, steel supplies from ICSOR were discontinued and supplies were obtained from the United States.
Production of steel helmets went on almost throughout the war. Occasionally there were hold ups for materials and for conditioning of tools. Regular shooting tests were conducted to ensure the helmets were up to specification and staff from the Director General Supplies Inspected each helmet.
The Transvaal Steel Pressing Syndicate pressed the helmets and trimmed them. Thereafter the three distinctive holes were punched in the Back rim, one hole in the crown to accept the head liner retaining brass screw and one hole on each side to rivet the chin strap fixings To. The stainless steel, anti-magnetic channel rim was then fitted and spot welded on the left side of the wearer. The helmets were sent For painting to Messrs. Herbert Evans & Co. (Pty) Ltd.
Helmets were first painted in the standard UDF green, then a darker UDF green and Later in a desert sand or those helmets destined for troops in the Italian campaign, in a brown. Jager Rand (Pty) Limited manufactured and Fitted the head linings and made delivery of the completed helmets to War Supplies.
Once the requirement of the Union Defence Forces had been met (unknown amount but probably in the region of 300 000), production continued and on 9 April 1945 the Transvaal Steel Pressing Syndicate pressed their one and half millionth helmet.
The excess helmets were supplied to the Eastern Group Supply Council (EGSC). This council was formed as a result of a conference held in Delhi India between October 25 and November 25 1940. At this conference delegates from Australia, New Zealand, South Africa, India, Southern Rhodesia, Kenya, Uganda, Tanganyika, Northern Rhodesia, Nyasaland, Zanzibar, Burma, Ceylon, Hong Kong Malaya and Palestine agreed to a joint war supply policy which would make use of the existing and potential capacity for war supply of each country. This would prevent duplication of effort and wasteful shipping from Great Britain. South Africa became the principal supplier of steel helmets to the EGSC. It is estimated that from February 1941 most helmets made in South Africa at a continued rate of 10 000 a week were sent to the EGSC. About one million, two hundred thousand helmets were thus exported to the EGSC.
It appears that the use of neck veils was never officially sanctioned but the wide spread use of neck veils in East Africa with the Polo Helmet, was probably the reason why the TSP included holes for a neck veil. It is not known who instructed the TSP to punch the three holes in the rear rim, but was probably an officer with East African experience.
Why were neck veils not worn with the steel helmet? By about September 1941 no further photographs show the use of any neck veils. It is assumed that a Routine Order from this period forbad the use of neck veils.