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Thread: .30-'06 conversion notes

  1. #21
    Happy Camper hcpookie's Avatar
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    OK - using that welded-in collar makes sense now for a BLOWBACK only. Gotcha!


    I assume Mach3 is a CAD program of some sort? That would be cool! IF IT WERE ME, I'd make a raw bolt blank with a small diameter opening in the face so that I could build it into whatever sized face I need on the lathe at a later date.


    Making my own bolts is on the menu. In fact it is one of the reasons I got the indexing head. I need more collets as it doesn't take the ones I have The challenge that I see is going to be drilling the small pin hole for the firing pin retainer in the hard steel. It is surely going to be a difficult task. The other things will be relatively simple tasks on the mill with a rotary table (or a lathe with a milling attachment). A slitting saw for the ejector groove. Then temper the metal to the approprate hardness for the metal in question. I have a big piece of 4340 steel but it is actually TOO BIG and I need to get a smaller piece LOL.


    Wow as I'm typing this a deer just walked through the trees in my backyard!
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  2. #22
    TRX
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    No, Mach3 is the CNC controller software. I haven't found any CAD software worth dog spit yet.

    Drilling the firing pin hole is no big deal; if you use a sprung pin the small hole is much shallower.

    It's the profile of the locking lugs that stumps me. I could use the manual machines and make square lugs, but it requires a cam-operated or CNC fourth axis to cut the lugs... though I bet there are some geezers out there who could do it by eye with a file and half a plug of Red Man.

  3. #23
    No Hope For Me 1biggun's Avatar
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    Counterboring and pinning still looks practical to me. Bolts are supposed to be tough, not hard, and thus should be machineable. You can take a file to yours and check. <grin>

    Yea there machine able they have to have some flex or they would be brittle. thre not soft by any streach of the imaganation. I have opend up bolt faces on the mill, filled lugs when truing the action etc.

    ALL that CNC stuff is before my time they didnt even have CNC in when I was taking classes they had some tape with holes punched in it ot some thing to control things. I should go take some classes. If i had the $$$$$ id buy a machine learn how to use it and go into bussiness. there is no reason the entire gun cant be duplicated in bettter steels. An american AK should be bassed on a 308win/ 5.56x51 IMOO and be usable for hunting and other real world situations.

    Build a super 3lug trunion and bolt that will handel 70,000 PSI and we could build
    300WSM and other magnum stuff. or better yet a milled magnum reciver and super bolt than we could build some classy looking stuff to.

  4. #24
    No Hope For Me 1biggun's Avatar
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    Wow as I'm typing this a deer just walked through the trees in my backyard!
    seasons open here I have the pistol sitting by the door and a orange coat with a tag on it just incase they come by.

  5. #25
    Happy Camper hcpookie's Avatar
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    Quote Originally Posted by TRX View Post
    It's the profile of the locking lugs that stumps me. I could use the manual machines and make square lugs, but it requires a cam-operated or CNC fourth axis to cut the lugs... though I bet there are some geezers out there who could do it by eye with a file and half a plug of Red Man.
    We discussed this a few months back on my "rotary table" thread, I think in the Tools section.

    What I took away from it is that they use a precision grinder which compensates for the hardness of the tool steel, and that you need a rotary table set up to cut passes along the length of the bolt. Rotate, cut, repeat. Assume it is a tilting head rotary table, and relocate the table at a 45 degree angle to the cutting axis, use the perpendicular axis to make the 45 degree part of the lugs. A slitting saw for the ejector groove and REALLY small bits for the pin holes to finish.

    Harden the steel to the appropriate temper for that metal and you can rely on the published yields for that particular hardness. Calculate bolt thrust using Gunter's forumla and you'll have a really good idea of how much it should be able to handle.

    Just thinking out loud. I have birthday money and plan to get that 4" tilting rotary table from Grizzly.
    Gunco Member #10

    http://pookieweb.net


    The "original" Boltcutter Rivet Squeezers:
    http://pookieweb.net/AK/rivet/boltcutters/boltcutter.htm


    Project Pink - the Pink and Blue AK-74:
    http://pookieweb.net/pink/pink.htm

  6. #26
    TRX
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    I guess there's no reason you can't take a dozen cuts on each cam surface.

    Mount the rotary table flat on the mill table. Make a fixture to hold the bolt parallel to the table; a block of steel with a pair of perpendicular holes would do, one for the bolt, one for bolting it to the table.

    Figure out your cuts on graph paper. Draw the bolt 5X or so, then use a ruler and protractor to figure how many degrees to turn the bolt before each cut. Make the cuts with the Y axis, in and out. Since the cam is a snail shape, you'll need to adjust the X (left to right) position slightly for each cut.

    Index to the next lug. You could mount a disc on the tail of the bolt with some pencil marks at the correct angles and line them up with a mark on the fixture.

    Use a file to dress the step at the corners of the lug where the bolt head curves downward, then dress the cam shape. Shouldn't take too many strokes to do it.

    After cutting all the lugs, hit them with Dykem or felt tip, put it in the bolt carrier, and cycle it to see how it contacts the trunnion lugs. File a bit here and there as needed.

    Hmm. I got so hung up on the CNC thing, it never occurred to me it could be done by hand. And for those who might boggle, Harold Brookshire showed me his camshaft prototyping setup back when he owned Ultradyne Cams. He made the master lobes for the cam grinders in that exact same way, making a bunch of cuts and smoothing them out with a polishing wheel. It was state of the art back in 1986; nowadays he doesn't touch any tools at all, he just generates the profile and emails it to one of the specialty grinders, who send the cam directly to his customer. Joe Lunati used to make his master lobes the same way.

    I also got hung up on somehow measuring the precise shape of the AK bolt cam shape... but I bet "eyeball is close enough" there, too. Cut the shape slightly "fat" and keep filing until it test-cycles okay, and it doesn't matter what the precise shape is.

    Hot dang, this looks doable...

  7. #27
    No Hope For Me 1biggun's Avatar
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    what ever metal that the latest and greatest AR bolts are being made form and what ever processes there using to treat there stuff is likely what would be best. I can think of very few things that have had as much research trying to make an existing sized object stonger..

    I likely cut the angles on the bolts lugs with a tool post grinder in the lathe set at the aproperiate angel and rotating the part chucked into the spindel by hand. I just need a hardend properly made 3lug bolt with square to the stem lugs thats slightly oversized. I can get the rest to fit. Id like od of the entire head a little larger to reduce the side to side play in the trunion as well

  8. #28
    TRX
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    I have a bar of 4140 I bought last summer. It's the same stuff the make many bolt-action bolts out of.

    Anyone have access to a Rockwell tester? It would be nice to know what the surface hardness is, or even to sacrifice a bolt and check it at various depths.

  9. #29
    No Hope For Me 1biggun's Avatar
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    some were here there was a member who did rockwell tests. what are the latest AR bolts made of?? If there is a better materail than what the current AK bolts are made from Id want to use it. a mistake with a bolt ot trunion is the one are were you can get hurt.

    Ive been tempted to take some courses at the MATC college in Madision WI. I hear they have a very Gun friendly instructer there. Id like to get the 411 on proper tempering technicues and have acess to the right stuff. i could brush up on my Mill and lathe skilles as well

  10. #30
    Gunco Veteran Viper Dude's Avatar
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    I do believe that many if not most gun bolts are machined from forgings. The forging process allows the metal grain to follow the shape and thus boosts strength vs bar stock or cast pieces, heat treat aside.

    Machining a bolt was often done with either a tracer mill or horizontal production mill using form cutters to create the desired radial shapes. A table-powered dividing head placed at angles to the table axis can create the symetical bevel cam shapes.

    Non-symetrical cam shapes such as are found on race car engine cams are best produced on CNC grinders these days. Exotic cam profiles date back to WW-II German technology brought home by a few GI's (Ed Iskenderian et al). The profiles necessitated new machining techniques to grind.

    I believe that these small gun bolts can be turned on a lathe and then milled using formed horizontal side cutters. A tool and cutter grinder will be needed to produce the special side cutter (unless you could fudge with a home-made fly-cutter).

    Unlike a Rubic Cube or a Chinese puzzle there are numerous solutions to this machining challenge usually dictated by what machinery you have at hand and the quantity of parts you wish to produce.

    VD

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