C2 shot peened half shafts - NCRS Discussion Boards

C2 shot peened half shafts

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  • Barbara S.
    Very Frequent User
    • April 30, 1981
    • 599

    C2 shot peened half shafts

    I see that according to my 65 JG, my half shafts are supposed to have a shot peened look. Just what exactly is a shot peened look and how do I recreate it?

    Thanks!
    Tony
  • Dick W.
    Former NCRS Director Region IV
    • June 30, 1985
    • 10483

    #2
    Re: C2 shot peened half shafts

    Shot peening is a process in which they take small steel shot and blast or peen the half shafts. This would relieve the stress from extrusion of the tube, forging of the end yokes and the welds. It is not easily reproduced unless you have access to someone with a shot peen cabinet. If you have aviation repair/rebuild facilities near by you should be able to find someone with the quipment
    Dick Whittington

    Comment

    • Wayne M.
      Expired
      • March 1, 1980
      • 6414

      #3
      Comparison: SB vs. C2 BB

      Tony:

      Hard to describe without having them in your hand and rotating under various lighting. Also very difficult to photograph. My late-production 396 is on the left; on the right is from a Feb '64. The latter was factory painted / mitted / dipped (take your controversial pick) in black paint, which came off with solvent, leaving the shiny surface -- note the blue-ing / brown-ing in the weld heat-affected zones. This discoloration is completely eliminated in the BB shot-peening operation. The entire BB tube shaft is treated, including the yokes (at least in the circumferential weld zone).

      Second pic shows the shiny '64 shaft better:


      Shot peening is EXTREMELY fine-grained. I'm no metallurgist, but I believe the intent is to mechanically stress relieve the surface, so as to eliminate fracture initiation imperfections.

      Have you found your lime-green paint dabs on your late 396 half-shafts yet ? (ain't this fun ?)
      Attached Files

      Comment

      • Bill W.
        Extremely Frequent Poster
        • March 1, 1980
        • 2000

        #4
        Re: Comparison: SB vs. C2 BB

        I like the greese pencil x on the bb shaft

        Comment

        • Duke W.
          Beyond Control Poster
          • January 1, 1993
          • 15610

          #5
          Re: Comparison: SB vs. C2 BB

          Shot peening work hardens the surface. As long as the surface is crack free, shot peening can prevent microscopic defects from developing into cracks, which yields better fatigue resistance and a more durable part in a cyclic loading application.

          It's a good process to use on connecting rods.

          There are various shot sizes, but most are very small - maybe on the order of a #8 shotgun load or smaller. Prior to shotpeening connecting rod flanks are usually smoothed from the as forged condition, and after shot peening the surface has a very fine roughness - much finer than as forged.

          But after forty years of surface rust, a shot peened half-shaft might be tough to distinguish from one that has not been shot peened.

          Duke

          Comment

          • Barbara S.
            Very Frequent User
            • April 30, 1981
            • 599

            #6
            Re: Comparison: SB vs. C2 BB

            Hey Wayne. I found the lime green on the half shafts and on the drive shaft. I have no signs of orange on the drive shaft though. Some restorations show the orange line parallel to the lime green, but no orange line on the circumfrance of my drive line.

            Yepper, I'm having fun. I'm getting tired of cleaning all of these d@mn bolts for plating though. The end is in sight!

            Tony

            Comment

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