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big-red-says

M-1 Helmet Production Breakage VI - Deja Vu

Big Red

Big Red here with a question from "Phil Connors"...

    So, TAKE FIVE!

    Phil asks,

    "Big Red, How did adding more companies to make up for breakage result in more breakage?"

    Great to hear from ya Phil,

    The short answer, for the exact same reasons the Ordnance Department was seeking a supplement to the McCord and Carnegie-Illinois contract to begin with, steel issues and poor fabricating techniques.

    Although Schlueter was contracted in the summer of 1942, they were not able to deliver their first finished helmet until January of 1943. During the delay from contract to production, Schlueter had to organize their production floor, attain equipment and have the necessary tooling fabricated. Once started they suffered all the growing pains of developing procedures specific to handling the unique and highly stressed nature of deep drawn manganese. Their situation was further complicated as they began fabricating with steel discs at the new standardized thinner gauge of 0.044-inches thick.

    Even with the foreknowledge that the highly stressed condition of the helmet was susceptible to cracking in the visor, if notches are left in the edges from damaged trimming dies, Schlueter suffered significantly from visor cracking. The losses to production breakage and age cracking as a result of damaged trimming dies was on the increase and Ordnance personnel struggled to impress upon both fabricators how important it was to maintain undamaged dies.

    When drawing and trimming objects from plain-carbon deep-drawing stock the potential of chipping the trimming die was low and even if there was a nick in the die the lack of residual stress in this type of steel would not foster cracking from the resultant notches.

    Unlike the steels McCord and Schlueter had experience working with, the hardness achieved in the manganese after the initial draw approached the hardness of the steel used in the trimming dies making the occurrence of chipping or nicking of the trimming dies extremely high. Since a notch combined with the highly stressed nature of the visor meant a crack it was imperative that both fabricators monitored and maintained healthy trimming dies.

    Adding to this chaos, Sharon Steel Company, Sharon, Pennsylvania joined the helmet production field as a steel supplier. Sharon Steel supplied helmet stock to both fabricators but was the only source for Schlueter. Having had initial assistance from the Ordnance Department, Sharon Steel knew that the primary reason behind previous helmet stock failure at the initial draw was due to undissolved carbides at the ingot phase. Unlike Carnegie-Illinois, who used an open-hearth furnace, Sharon Steel utilized an electric arc furnace, which proved superior at controlling temperature and duration of heat resulting in low occurrences of undissolved carbides however, their work practices introduced two new major steel defects, decarburization and the formation of Martensite.

    Steel with these defects is not conducive to deep drawing because it is rigid and brittle and as it was provided to both fabricators it significantly compounded the production breakage and delayed cracking problem.

    And Phil,

    if your friends want to know how you gained your intel, tell em

     

    Big Red Says!

    FIVE'S OVER  -  MOVE OUT!


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    2 comments

    • Hey Allen,
      In order to answer your question I will have to do some old fashioned country boy ’figurin" :)
      First we need to accept that helmets with service and/or age cracking are part of the total procured because they cracked after issue.
      Second we need to accept that production breakage losses would have been fabricator waste meaning, the percent breakage loss would be in addition to the total procured.
      No production documents from the fabricators has been found accounting for their waste percentage but, if we take what we know about the breakage percentages from the beginning and end of the war, we can theorize an average minimum of 3% to a maximum of 5% loss in the initial draw and spanking operations.
      This means that a minimum of 600,000 to 1,100,000 helmets would have been lost to production breakage or worst case, they would have had to process 23,100,000 helmet discs to deliver 22,000,000 helmets.

      Seamus "Big Red" O'Rorke

    • This is a fascinating subject. I always believed that the American steel helmet was the best designed for head protection during the second world war. Out of the 22 million that were produced during the war what percentage was there a breakage problem ?

      Allen Childers

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