Unusual Barrel threads?

Discussion in 'AK & SKS Discussion' started by AK-47, Apr 8, 2010.

  1. AK-47

    AK-47 New Member

    Ok... I have an Armory USA Bulgarian AK in 7.62 and the threads on the barrel aren't the regular 14-1 left or the larger 24mm x 1.5 They are a right hand thread that NOBODY I have talked to can seem to identify including my gunsmith. I took the flash hider that came on the gun to various hardware stores and auto places and it doesn't match up with any fine thread or machine thread in standard or metric.

    So the question is... Is there some rare little known right hand thread pattern for AK's that nobody seems to know about or is my gun just a mutt?
  2. skullcrusher

    skullcrusher New Member

    How are you measuring the pitch and lead? If you can find a machine shop with real thread gauges, you will find out. That is unless someone here knows for sure.

    Hint: just pulling standard arabic and metric threaded screws and bolts from the general hardware store won't give you the answer you seek if it is not a popular thread.

  3. AK-47

    AK-47 New Member

    I had one guy at local Napa that actually know his s#it use a digital thread gauge on it and he said it was registering between 13 and 14 mm. Im stating to think they might have messed up the threads at the factory and just made my flash hider close enough to match it since nobody can think of any thread patterns between the 14lh and the 24rh
  4. BillM

    BillM Well-Known Member Supporter

    You need the outside diameter of the thread (called the major diameter) plus
    the pitch of the thread---the number of threads per inch or the metric distance
    from one thread to the next. Also LH or RH, and the thread type. Most standard
    threads are 60°. There are also 55°, acme, and other weird stuff.

    The major diameter is easy. Micrometer, cheap pair of calipers, whatever.
    The pitch is easiest to measure if you have a set of pitch gauges. They look
    kind of like a set of feeler gauges, but each blade has a different thread cut into
    it. Check with both metric and standard gauges---there is no guarantee that the
    thread is metric. It's easier to check pitch on outside threads (barrel) than inside
    threads. Find a job shop machinist, or a gunsmith that does lathe work. They
    will have thread pitch gauges.

    9/16-32 is not an uncommon thread fror flash hiders. It's what FAL's use, but on
    them it's a LH thread.