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Discussion Starter · #1 · (Edited)
Building my first kit. Not sure about headspacing(where to check, how to check, etc.). I've been reading all the info. I can find, but still confused. Need some photos or illustrations. Guess what I really need to know is how would you adjust the headspacing if it was off? And, what are the tolerances? Thanks.
 

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You need to get a set of go no go gauges. The bolt should not lock up on the no go. If it does then the barrel has to be inserted deeper into the trunion until it will close on the go & not on the no go. That is my understanding anyway.We are onyl talking a few thousanths
 

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Discussion Starter · #3 ·
erikk said:
You need to get a set of go no go gauges. The bolt should not lock up on the no go. If it does then the barrel has to be inserted deeper into the trunion until it will close on the go & not on the no go. That is my understanding anyway.We are onyl talking a few thousanths

Thanks for at least responding. I' m still confused though. When you say "GO-NO GO" I'm reminded of setting the gap on the points of my 63 chevy, with .019 being the"GO" and .020 being the "NO GO" with my feeler gauge. It could be hard sometimes but at least you could halfway see. And if I read correctly on one of these web sites, I believe .0009 was mentioned. In my math book thats nine tenthousands of an inch. How can anyone hammer or even press to such tolerances. I've read about clamping the trunnion in a vise, using sledge hammers, etc., but this seems awful crude for such precision machining & tolerances. And the hydraulic press, yea that's what I would try, without a sure "STOP or SEAT" how do you control movement. Guess I'm just gonna have to figure it out on my on. Thanks again for at least responding!!!!
 

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I would have to guess my method of pressing is the most "crude" and I can fine tune by applying less hydrolic pressure and then I use a brass rod and I tap on it with a smaller hammer, then the movement is much smaller. Yes at times I have gone past and had to drive it back but with some common sence and care it can be done very accureatly. I find hydrolic and tapping to be the most accurate for me. The higher the hydrolic pressure before I tap the trunion the bigger the jump it takes, less pressure a smaller jump is made. this can be brought rite down to tiny steps. when I do a polish kit with the hole allready drilled I install the barrel so the hole in the trunion exactly lines up with the notch in the barrel and most often get it exact the first time, without going past. when dooing this you can clearly look through and see if you are off even by a few thousandths. after it is centered then I check head space just to be certain.
I certainly understand your wondering about the precision of the methods but it can be done and it can be done well without great dificulty.
 

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you have a good comparison with your feeler guages thinking about checking head space. with your points the 19 should fit and the 20 should not fit. if the 19 will not then you would open them up more. if the 20 fit then you would have to close them some. It is basicaly the same for your go, no-go the bolt should close fully on the go, and the bolt should not close on the no-go. ...... If the bold will not close on the go, then you need to open up the space some. if the bolt closes on the no-go then you need to close up the space some. you adjust the space by moveing the barrel in or out, just like moveing that one side of the points in or out.
you say this is your first kit,,,, will you tell me what you have , is this a matching number compleat kit or is this miss matched parts. dose your trunion allready have a hole on it for the locking pin. it will be about 1/4 inch. If you have a barrel and trunion from a matching number set then must likely all you will have to do is line up the holes and head space will be ok, but still check to be safe. if they are miss matched then you will have to press and test again and again till you get it, then install the pin maby even drill a tiny bit and install an oversized pin. realy it is not that bad either way.
do not get dishartened, one step at a time it will all work out great in the end ... HAY THINK HOW EASY THE SECOND ONE WILL BE :smile:
 

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Discussion Starter · #6 ·
hotbarrel said:
I would have to guess my method of pressing is the most "crude" and I can fine tune by applying less hydrolic pressure and then I use a brass rod and I tap on it with a smaller hammer, then the movement is much smaller. Yes at times I have gone past and had to drive it back but with some common sence and care it can be done very accureatly. I find hydrolic and tapping to be the most accurate for me. The higher the hydrolic pressure before I tap the trunion the bigger the jump it takes, less pressure a smaller jump is made. this can be brought rite down to tiny steps. when I do a polish kit with the hole allready drilled I install the barrel so the hole in the trunion exactly lines up with the notch in the barrel and most often get it exact the first time, without going past. when dooing this you can clearly look through and see if you are off even by a few thousandths. after it is centered then I check head space just to be certain.
I certainly understand your wondering about the precision of the methods but it can be done and it can be done well without great dificulty.
Thanks. I wondered if things wouldn't be close if the holes & notch were alligned.
 

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Discussion Starter · #7 ·
hotbarrel said:
you have a good comparison with your feeler guages thinking about checking head space. with your points the 19 should fit and the 20 should not fit. if the 19 will not then you would open them up more. if the 20 fit then you would have to close them some. It is basicaly the same for your go, no-go the bolt should close fully on the go, and the bolt should not close on the no-go. ...... If the bold will not close on the go, then you need to open up the space some. if the bolt closes on the no-go then you need to close up the space some. you adjust the space by moveing the barrel in or out, just like moveing that one side of the points in or out.
you say this is your first kit,,,, will you tell me what you have , is this a matching number compleat kit or is this miss matched parts. dose your trunion allready have a hole on it for the locking pin. it will be about 1/4 inch. If you have a barrel and trunion from a matching number set then must likely all you will have to do is line up the holes and head space will be ok, but still check to be safe. if they are miss matched then you will have to press and test again and again till you get it, then install the pin maby even drill a tiny bit and install an oversized pin. realy it is not that bad either way.
do not get dishartened, one step at a time it will all work out great in the end ... HAY THINK HOW EASY THE SECOND ONE WILL BE :smile:
My son bought a MAK 90 (less receiver) at a show. The trunion is still on the barrel. Then I bought an AMD 63 kit with matching #'s. I was hoping to do the builds without disassembly, but in case I needed to remove the trunion, I wanted to "be informed". Thanks again & maybe I can keep everyone informed on how these builds go.
 

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if your trunions are still atached then your head space should be fine, but I recomend you still check. also I bet your mad63 will have the trunion still on too. you can think about screwing the front trunion on and riveting the rest if you like, that is what I did with my 63. it was fast and easy. you can hammer the rear trunion rivets and with a custom ground "punch" you can hammer the trigger guard rivets too, this way you do not need a press at all.. how is that for cool. AGAIN PLEASE keep us posted and we all love pics as it goes :smile:
 

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Discussion Starter · #9 ·
hotbarrel said:
if your trunions are still atached then your head space should be fine, but I recomend you still check. also I bet your mad63 will have the trunion still on too. you can think about screwing the front trunion on and riveting the rest if you like, that is what I did with my 63. it was fast and easy. you can hammer the rear trunion rivets and with a custom ground "punch" you can hammer the trigger guard rivets too, this way you do not need a press at all.. how is that for cool. AGAIN PLEASE keep us posted and we all love pics as it goes :smile:
Thanks. Well, I'll try to include some pictures, although my children will have to do it!! Ain't too computer savvy. I just work with metal.
 

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Discussion Starter · #10 ·
AK Headspace measuring

Just found the answers to my original questions at surplusrifle.com (Measuring Headspace). Good information along with illustrations.
 

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-Hammering rivets-

Hey hotbarrel,
Do you have any pics of the hammering of the rivets for the trigger guard or any if at all?
How did they turn out? Did you use some kind of inverted rivet set for the button head?
Please fill me in! :confused:
Thanks....Shadow





hotbarrel said:
if your trunions are still atached then your head space should be fine, but I recomend you still check. also I bet your mad63 will have the trunion still on too. you can think about screwing the front trunion on and riveting the rest if you like, that is what I did with my 63. it was fast and easy. you can hammer the rear trunion rivets and with a custom ground "punch" you can hammer the trigger guard rivets too, this way you do not need a press at all.. how is that for cool. AGAIN PLEASE keep us posted and we all love pics as it goes :smile:
 

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I have posted pics of my tools and they are all very simpal. As for pisc of me hammering no pics. I have made a few detailed threads on my low tec riveting methods. low tec with great results. ckeack my thread " rivet tips " and " my polish kit ". I made another thread on riveting but I can not remmber the name at this moment.
As for hammering the rivets here is a quick rundown. hammering works for the long rivets only.
firs are you useing swell necks? if yes you need to be shure the trunion has a small countersink in it allready, if not you will need to put on in. this is for the reciever it form into by the swell. then be shure the holes in your trunion are aligned, if not egg out the holes to align. put in the rivet and tap the head to drive the swell conforming the reciever to the countersink. Now flip the reciever over and very carefully hammer the rivet down. you can grind a dimpel into your anvil to keep the head nice and round. after a few blows the rivet will start to get tight as it gets fat this is the time to tap the head again tight against the reciever. if the rivet is loose than hammer it some more and tap the head again . the idea is to end up with the head tight against the reciever. Carefull hammering will result in a cylindericay head, now take a 1/8 inch drill and drill a hole in a piece of scrap steal then countersink the hole till the OD os the same OD as the cylinderical head. tap the rivet into the countersink to give it a tappered look, it will look prety nice and with a littel finish work it will look great.

CAREFULL HAMMERING will mean a watching every blow and how the metal reacts to it and corecting the next blow to get the desired result. usualy only the firsty few blows come down straight then the rivet starts to bend not crush. you will have to you will have to prevent this from bending over by hammering the rivet back ware you want it. I have had to use a punch once when it bent too far to bring it bach up. often the hammer will be striking the head comming down at 45 degrees. hammer head parele to reciever but traveting at an angle. I use a striking hammer and a 16 oz framming hammer.
I highly recomend you practise first by drilling a few holes in a piece of scrap, put a nail the same size as a rivet through the hole then cut it off with the same length sticking out as a rivet. after a few you will see how the metal reacts and be an expert. it is predictable. this is just like old time blacksmith. I realy enjoy this kind of work "hammering parts into shape"

so much for a quick run down HAHAhah honestly you can get great results hammering by hand.

oh yes you can grind a dimppel into the end of a punch to shape the hammered head round if you do not like the countersink results . with a dimpeled punch you can get the head as ropund as you like.
 

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as for the trigger guard rivets, take a piece of round 7/8" or 1" stock about 6 inch long. grind out a notch for the rali in the side and another notch for the center support. then hammer the heads down thies heads are not seen like the others because they are inside the reciever so they do not need to be as beautifull. grind out the sides and test fit the tool if it hits a rail ao the support then grind out some more. you will see this tool someware in the post I mentioned above. my trigger rivet tool is shorter because I use it in an arbor press but if you make it longer you can hold it and just hammer them down. rember dimpals in your anvil if you require round heads on the outside
 

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-Pressing the "Hot barrel"-

Hotbarrel,
You've said you've done a few polish kits, and pressed the barrel into the trunnion. Well my next step on my PMKMS kit from global trades is to do the same.
Could you give me any good advice on doing so?
Could I use a peice of oak and just tap with a 2 pound hammer untill the notch/pin lines up with the barrel and trunnion?
Should my head space be ok then?
How do you check (your) head space?
I don't have any guages, and can't afford them.....Could it be possable to use a dummy round of some sort to see if the bolt functions properly?
Ya know (bolt closed..Go)!, (Bolt open..No go)! Or is there much more precision involved?
It's just a thought.
Thanks .......Shadow



hotbarrel said:
I would have to guess my method of pressing is the most "crude" and I can fine tune by applying less hydrolic pressure and then I use a brass rod and I tap on it with a smaller hammer, then the movement is much smaller. Yes at times I have gone past and had to drive it back but with some common sence and care it can be done very accureatly. I find hydrolic and tapping to be the most accurate for me. The higher the hydrolic pressure before I tap the trunion the bigger the jump it takes, less pressure a smaller jump is made. this can be brought rite down to tiny steps. when I do a polish kit with the hole allready drilled I install the barrel so the hole in the trunion exactly lines up with the notch in the barrel and most often get it exact the first time, without going past. when dooing this you can clearly look through and see if you are off even by a few thousandths. after it is centered then I check head space just to be certain.
I certainly understand your wondering about the precision of the methods but it can be done and it can be done well without great dificulty.
 

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shadow29483 said:
Hotbarrel,
How do you check (your) head space?
I don't have any guages, and can't afford them.....Could it be possable to use a dummy round of some sort to see if the bolt functions properly?
Ya know (bolt closed..Go)!, (Bolt open..No go)! Or is there much more precision involved?
It's just a thought.
Thanks .......Shadow
Shadow-- It's pretty hard for us to hurt ourselves in this hobby short of idiotic "gun accidents".

The exception involves excessive headspace.

You only need the no-go. $20 bought my last one (I think).

Look at it as saving the medical deductable for facial reconstruction.
 
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