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S&W 639 Slide Crack?

OLDCOP
I've put this quesntion on another site but want have a broader exposure, so: I have a 639 slide which has a very thin crack at the point where the cutout for the extractor meets the cutout for the frame. My thought is that it shouldn't be a problem and appears to just be a stress crack from the machining. Does anyone have any experience or knowledge about this. I'm also looking for a frame to build out this piece. I've been told a 39, 439 and 639 frame will accept the 639 slide. Yea or nay? I thank you!
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Comments

4 comments

Date Votes
  • Hawk Carse
    I don't think it will blow up but I don't think it a good place to start if you have to buy the rest of the gun to finish it out.
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  • perry shooter
    IMHO a crack no matter how small does not happen during machining but rather by STRESS occurring during the course of firing. Unless the material the slide or frame is manufactured from has defects "voids" . Me Thinks you tried one too many +P+ handloads [:(][xx(][V]. I would see if S&W would replace the slide baring that, find another slide or frame at a gun show and take your pistol and see if all good parts fits.
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  • David Nunn
    Before you go to buying a lot of parts and messing around with it, contact this guy:

    http://www.lsgmfg.com/

    Send him pictures, and see what he has to say. Tell him I sent you.
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  • v35
    This is the weakest point in the slide being located at the smallest crossectional area of the slide between locking lugs and breech face.
    It would be a mistake to weld repair it. It's an important argument for any highly stressed gun parts being properly forged.
    Sharp interior corners (fillets) formed by machining operations are stress risers that increase stresses up to 400%. That's why maximum radaii should always be used in highly stressed areas when possible.
    Even if the part was perfectly made from perfectly clean steel, repeated stresses, magnified by stress risers are likely to generate a crack at the sharp corner that progress until the part separates.
    If you were to see the surface of the break, I'll bet you'd see the typical conchoidal pattern of a classical, progressive "fatigue" failure.
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