FNG here looking for advise. How do you match up parts kits and receivers? I can find parts kits and I can find 80% or receiver flats, but how do you guys know which receiver will work with which kit??? I would love to put together a couple, but everytime I go shopping I get frustrated and turn to something more "clear". Help me connect the dots!

This is literally the only thing holding me back from building. I've built probably a dozen ARs including 80%ers, probably up to 6 sten builds now and various other S/A smgs. Saving up for a 1919 kit as I type. I have an entire machine shop at my disposal and have close to 15 years as a machinist. Please recommend me some reading material or something to make it a little easier to understand.

Thanks for your help, looking forward to piecing this together.

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I'm going to go at this systematically, so stay with me as this thread might get really long. We'll start with caliber. Do you want (multiples are acceptable):

7.62x39, 5.45x39, 5.56x45, 7.62x54R, 7.62x51, or other?

Google AKFiles

Receivers are pretty universal. More about markings, physical correctness, and what stock condition.

RPKs and some yugo guns use a thicker receiver.

If you tell us what parts kit we can help you better.  

First one will probably just stick with 7.62x39 fixed stock. Might be interested in a 5.45x39 or a krink after that. I was eyeing the Romanian kits that arms of america has listed. But then I go to look at their receivers and its all polish,  hungarian, yugo, etc. They do list a MD63 receiver but says for use with underfolder? I just don't know all the ins and outs of this to match them up.

The Romanian fixed stock kits are AKM pattern AK's. So any 7.62x39 AKM receiver, like the Morrissey AKM-47 receivers at AoA, would work. It doesn't really matter what country it says for the receiver so long as it's AKM based and fixed stock. If you want the build to be very "correct" in a historical sense then there are other options for the receiver. For 80% receivers I'd recommend the Polish AKM blanks, also available from AoA since you're already looking there.

Also, you can post the links to the items you want to get and we can confirm that they'll work together.

Thanks for your help! Maybe I'll just confirm compatibility with you guys before I order any builds. Can you confirm that this receiver,
http://armsofamerica.com/polishakreceiverblank-sale-39centersupportrivetandrailspackage-1.aspx
and this kit,
http://armsofamerica.com/romanianmilitarymodel1975akm47partskitnobarrel-1-1-1.aspx

work together? Maybe there is a more "accurate" receiver out there? Maybe a few extra pieces needed, like a rivet kit, etc. Anything else I should look out for, or maybe a better deal? Do the receivers come with dimensions like the stens or is it a figure it out yourself build? You guys have been the most helpful out of anybody, I really appreciate it.

Childers makes very accurate receivers.

Recreator is another but I like Childers more.

Your aware those 80s will require a spot welder with special jaws and a way to heat treat the receiver?

AKbuilder has all your odds and ends like rivets and barrels.

Yes, those will work together. The most accurate receiver would be from 74u LLC (other than an actual Romanian receiver, of course), but you'll pay for it with money an time. In this case, a Childers would be really good as well, but they're not the really accurate for AK-74's if you ever go that route. The 80% receivers do not come with the dimensions. AK-Builder has a jig that aligns all the hole for you, as does Childers.

Thanks for the tip on childers. Looks like he will be getting some of my money, especially since his blanks are already heat treated. I assume the polish rails will work if I order them at the same time.

I can heat treat if I have to, no biggie. I can also build a spot welder if I have to, might just drill holes and plug weld with the tig though..

I've saved some money on past builds by finding machinist drawings of receivers instead of buying jigs, but the layout tools from akbuilder looks heavy duty and cheap enough to last thru a couple. I see this snowballing like my AR addiction did...

The problem with the drawings available online is that most of them have conflicting measurements and I'm not sure any of them are considered exactly right. I'm sure this is a result of the multitude of different manufacturers in the AK world.

I have the original AKM blueprint. Send me an email if you want it.

Most of the Euro pattern ak's are similar. The Yugo ak is a different animal. It uses a different frame and trunions, the barrels are thicker, etc...
The easiest route would be to get a parts kit with a barrel fitted and head spaced to the trunion as done by ak builder and others. Some have had major rust problems with the NoDak
receivers, but I have not had serious issues with this. NoDak makes the correct frame for not all but most aks. You can still build on any Euro pattern ak frame but you may have to
do some tweaking.

Dont tig weld the rails.. Use a Childers receiver for your first build until you get the hang of it and it will also be a great template for future reference. Proper tools, proper rivets and techniques are the rule and will save you a lot of headaches .