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5/8 18 threads

Discussion in 'Gunsmithing and Repairs' started by billymarr, Jan 16, 2013.

  1. billymarr

    billymarr Well-Known Member

    would these be fine for holding a muzzle brake. I am building a brake and have everything for threading 18 thread pitch. I plan on using setscrews too. What are you thoughts?
  2. rcmodel

    rcmodel Member in memoriam

    What caliber muzzle brake??

    Muzzle brake threads are pretty industry standard now by caliber.

    That prevents Billy Bubba from screwing a .223 muzzle device on a .308 rifle barrel, and clamping it on with set screws...

    But in general, fine threads are used to get more thread purchase.

    1/2"-28, 9/16"-24, and 5/8"-24 is industry standard, depending on caliber.

    My best advice is to either do it right.
    Or don't do it at all.

  3. dubbleA

    dubbleA Well-Known Member

    You definitely want the threads on the barrel to be concentric with the bore, same thing with the brake or muzzle device. To achieve that you will need to single point thread thread them on a lathe or mill.

    Not certain but it sounds as if you are going to use a tap and die set when you say you are set up for 5/8-18. Isuppose that could work if the exit hole is big enough to take in the misalignment but then that defeats the purpose of a brake.

    Again, single point thread and dial in the piece to within a few .0001" from the bore is the way to go. Both shoulders will be perfectly perpendicular also and when tightened wont cause any alignment problems. No set screws needed unless you are talking about a pinch bolt.
  4. billymarr

    billymarr Well-Known Member

    Yea decided to go with 5/8 24 I can always cut an adapter. Still toying with the idea. Thanks for the input though.
  5. Kp321

    Kp321 Well-Known Member

    Some barrels do not have enough beef to use 5/8 threads. I normally use 9/16-18 for brakes.
  6. brickeyee

    brickeyee Well-Known Member

    Fine threads for hard material, coarse threads for softer (weaker) materials.
  7. Shimitup

    Shimitup Well-Known Member

    A major consideration behind using fine threads is that they do not tend to unscrew themselves in applications involving thermal and vibration stresses. A primary factor in most gun screws being extra fine.

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