[Hooch]

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.

 

[Hooch]

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!!!!

 

[Hooch]

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.

 

[Hooch]

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.

 

[Hooch]

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.

 

[Hooch]

AK Headspace measuring

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