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Thread: Very poor man's bend jig - lol

  1. #201
    GuncoHolic zteknik's Avatar
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    No Hope For Me Coils's Avatar
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    Now, how and where do i need to heat treat the receiver?
    I didn't look at the other site but there's info on here, heat treating, but you need to do the FCG pin holes & ejector.
    "Government is not the solution to our problem, government is the problem" Ronald Reagan

  3. #203
    Gunco Member chuangtzu's Avatar
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    I'm giving this jig a try in an attempt to build a Romanian AK with the most ghetto "shop" this side of the Atlantic...

    I built the jig, but it seems that my alignment holes are a bit off. If I bend my flat as-is, the right side of the rear trunnion will be 2mm higher than the left side and the left side of the front trunnion will be 1mm higher than the right side. My flat is "cockeyed" in the jig. This means that the holes furthest from the point that is centered (which is somewhere near the rear of the mag well) will be the most mis-aligned. Fortunately, these furthest holes are the trunnion holes, and since I'm doing a screw build I'll be drilling them out to 1/4" anyway which will re-align them. Nevertheless, the axis pin holes will be slightly mis-aligned.

    What are the tolerances here? Is +/-1mm something noticeable in final assembly? Should I go ahead and bend? Or should I build another jig...?

    If the answer is to build another jig, what can I do to make sure the holes are centered this time? Last time I marked the holes with a marker, measured center by setting my calipers to half the width of the bar stock and using them to lightly score the surface of the bar from both sides (the lines overlapped, indicating they were centered). Then I centerpunched on the line and used the drill press to drill 1/8" holes centered as best I could on the dent from the centerpunch. I guess that wasn't good enough...


  4. #204
    Gunco Maniac sjohnson's Avatar
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    Don't use the alignment holes, but measure and move the flat until both sides stick out an equal amount from the center piece.

    You're introducing error early on if the sides aren't equal, error which will compound itself in assembly and function as you fit parts. Start out as precise as possible, keep it as precise as possible, and the little errors that we all ultimately will make should remain small and easily compensated for.
    I have a daughter. I tell her, "911 is what you dial after you're raped. 1911 is what you should have before they try."

  5. #205
    Gunco Member chuangtzu's Avatar
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    Quote Originally Posted by sjohnson View Post
    Don't use the alignment holes, but measure and move the flat until both sides stick out an equal amount from the center piece.
    Aha! That's it...

    I actually thought of that, but must have promptly forgotten it...

    Thanks for the sanity check.

  6. #206
    Gunco Member chuangtzu's Avatar
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    Well, I've bent 2 flats using this method so far. One using a hammer and one using bolts to pull the flat through the angle irons. Both methods produced perfectly symmetrical bends but the hammered flat was slightly warped due to one side of the angle iron jig being slightly too tight. This warp carried through all the way to the bending of the upper rails leaving a slight dip in the middle of the rails. Nevertheless, I kept going with it just to see what would happen and it turns out the bolt carrier will cycle fine in such a mangled POS! The second one bent much more nicely and squared up great.

    My main problem right now is that when I am hammering the upper rails flat, the bar stock pieces within the receiver gradually slip down inside the receiver so that by the time I'm done hammering, the inside of the receiver is under-sized. Even worse, on the second receiver, the bar stock angled slightly and one of the receiver's "U-arms" is 30 thousandths longer in the front than the other side. The rear arms are 50 thousandths short of spec.

    I'll most likely need to trim the stock due to the receiver being undersized and the uneven rails might cant the magazine leading to trouble feeding. It's also possible that the bolt will be riding too low and interfere too much with the hammer during recoil. It'll probably still cycle fine but the perfectionist in me wants a better way to bend the upper rails.

  7. #207
    Gunco Maniac sjohnson's Avatar
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    For a better upper rail bend, you really need a full size male die.

    For the best upper rail bend, you need the AK-Builder die, with upper rail step-down!
    I have a daughter. I tell her, "911 is what you dial after you're raped. 1911 is what you should have before they try."

  8. #208
    GuncoHolic zteknik's Avatar
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    Quote Originally Posted by sjohnson View Post
    For a better upper rail bend, you really need a full size male die.

    For the best upper rail bend, you need the AK-Builder die, with upper rail step-down!
    if your gonna be building a few the ak builder jig is a must!!itll cost you less in the long run!-no more futzed up flats!
    after i scrapped 2 i said enuff!!
    hey sj is the step down attatchment realy worth it?
    and is it possible to use on flats allready bent?

  9. #209
    Gunco Maniac sjohnson's Avatar
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    For semi builds it's probably not.

    No matter the need, it's still the BEST. And if the bent flats are spec, yes it'll work on already bent flats.
    I have a daughter. I tell her, "911 is what you dial after you're raped. 1911 is what you should have before they try."

  10. #210
    Gunco Member chuangtzu's Avatar
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    Quote Originally Posted by zteknik View Post
    if your gonna be building a few the ak builder jig is a must!!itll cost you less in the long run!-no more futzed up flats!
    I only planned on building one, but the futzed first one caused me to build a second. If this doesn't work though, I might look into renting a jig from somebody.

    What does the step jig do that the normal jig doesn't? I take it there is supposed to be a step in the upper rails but I have no idea what this means...

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