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I never see much talk on building from milled reciever kits. I know about the Ohms research method.Or some folks grind down the trunnions and use stamped recievers. I'd like to try and weld up a patch section and keep the milled look. I bought some 4130 steel in various thicknesses & some special mig wire for welding dissimilar metals. I have a milled Yugo RPK kit I want to build this way and would like to hear if and how others are using milled kits?
Thanks, Brad
 

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I've been thinking about doing the same thing. Ultimately I want to do it to a Russian, but plan to practice on a Yugo first. Been wondering what the material is. I see you are planning on 4130. How sure are you that it is 4130? I was just thinking about trying mild steel. There is not much stress at that part of the receiver. Figured I would use ox/acc welding since I dont have a TIG.
 

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I have done it on several russian kits , i used 4130 aircraft plate 5/23" thick , the russian steel is purty close to a U.S. 86-20 type casehardened steel- i know this from how it welds , and for the russiand to have had massproduced these - this would make the most sense-, to put one together right & have it look decent -it is alot of work, best to use a TIG to put it back together - i can post some pics if it would help !
 

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Discussion Starter #4
ozzy the nuke said:
I've been thinking about doing the same thing. Ultimately I want to do it to a Russian, but plan to practice on a Yugo first. Been wondering what the material is. I see you are planning on 4130. How sure are you that it is 4130? I was just thinking about trying mild steel. There is not much stress at that part of the receiver. Figured I would use ox/acc welding since I dont have a TIG.
I also plan to practice on a $59.00 Yugo kit. I'm sure the Russians did not use 4130. It's just the best thing available for gun work to me. It takes well to heat treating.It will be alot of work as none of the thicknesses from AircraftSpruce are exactly the same as the reciever stubs.I don't have Tig yet either. But the mig wire I found is made exactly for this type of situation. I wish I had good blueprint of a milled reciever instead of just guessing how it should look. I like a challenge though!
 

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Buzgun said:
I have done it on several russian kits , i used 4130 aircraft plate 5/23" thick , the russian steel is purty close to a U.S. 86-20 type casehardened steel- i know this from how it welds , and for the russiand to have had massproduced these - this would make the most sense-, to put one together right & have it look decent -it is alot of work, best to use a TIG to put it back together - i can post some pics if it would help !
Pictures would be great! I don't have Tig yet, but may before this project gets done. At least the RPK. Actually I preffer stick welding for this type of work. My welders got ruined along with everything else in Hurricane Charley & I have only replaced the MIG so far.The mig wire I found is made for joining hard and spring steels of dissimilar types. Stainless or carbon. I like doing things others say can't be done.
 

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Alright, looks like we have a thread going here. I am thinking it is about time to get moving on this project. Got my jewelers torch running again (bad hoses).

Pics would be great Buz! And any tips you want to offer too. :grin:

Thats good info on the steel type. What type of filler wire did you find works best?

I dont have any blue prints, but I do have an SLR95 that I can use for a pattern. I will probably mill out the middle sections and weld them up. If you dont beat me to it Brad, I can send you the dimensions once I get started.

I have been concerned about how close I can get them to match. I think I can do a decent job with the jewelers torch. Dont plan on buying a TIG soon.
 

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Count me in too...

I just picked up an excellent quality Yugo UF today. I have a MIG, drill press and several grinders. I'm looking for steel filler tomorrow.
 

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Bradrock said:
Buzgun said:
I have done it on several russian kits , i used 4130 aircraft plate 5/23" thick , the russian steel is purty close to a U.S. 86-20 type casehardened steel- i know this from how it welds , and for the russiand to have had massproduced these - this would make the most sense-, to put one together right & have it look decent -it is alot of work, best to use a TIG to put it back together - i can post some pics if it would help !
Pictures would be great! I don't have Tig yet, but may before this project gets done. At least the RPK. Actually I preffer stick welding for this type of work. My welders got ruined along with everything else in Hurricane Charley & I have only replaced the MIG so far.The mig wire I found is made for joining hard and spring steels of dissimilar types. Stainless or carbon. I like doing things others say can't be done.
Brad & OZZIE , you could use mild-( 10-18 ) steel to make these side plates- it would be easier to weld this metal - less chance of warping , but you would HAVE TO weld around fire controll group holes with a 4130 type weld rod to harden up these holes -( make sure you get full penetration with rod) - otherwise your hammer & trigger pins will "egg out" holes on U-after about 200 rds. - cus of the soft metal-----

this is the method i have used , you may have to change some things - from below "directions" to suit your needs or the equipment U are using.

HERE IS WHAT u WILL NEED BOYS :

12/12" - 5/32" - 4130 steel aircraft plate(to make sideplates)
.080 - 2" wide ground flatstock ( to make trigger guard piece)- not O-1 oil harding ! -- this sht turns to glass when U weld on it !!
for MIG -- ER70S2 wire ( to weld receiver components together)
some harder weld wire (4130) to make upper rail -weld bead- harder for bearing surface.
1/4" x2" ground flat stock - to use as a straight edge to weld sideplates on flush with Yugo cut receiver stub
.009 -- 9 thous. of inch THICK-copper shim foil - ( if U want the gun to look bad ass , and not be just a shooter)

MIG would work - cept when it comes to the right sideplate --( as the method i use is to fabricate the sideplates first , i.e. make your rails , and grind , or mill slots for bolt carrier the 5/32 material will have to be thined to approx. 80thous. thick inside in F.C.G. areas - so E-clips will go over Ham. & trig pins- - at the point U have both sideplates made - U weld the left one on first , from inside MAG. well - you must only weld a 3/8 -1/4" section at a time & let cool in between , or plates will go squirrley on you , and warp either up-or down - you will have to make sure left plate is welded on to approx. .015 - ( fifteen thous . of inch) tollerance - either tipped up or down within this tollerance - otherwise your bolt carrier will not float smoothly back & forth - & will bind- ( you will be pissed off if you go through with all this work- and this happens-so this is CRITICAL !)-
to acheve this tollerance measure with verniers & a straight edge from the begining point of plate weld joint is - to approx 5-1/2" to rear of plate this will determine if sideplate is tipped up or down - you adjust your weld direction to compensate for this -i.e. if it is tipped up a little you put a little more heat down low on weld joint, ----- you then repeat with right sideplate - once you get right & left sideplates welded on squarley - the rest is purdy easy !!! --- you may run into trouble fitting the MIG torch inside magwell to weld right sideplate from inside first not much room in there,---- then U weld the outside of sideplate --- I have a TIG torch with a small flexible head and a very small - 1/16" Tungsten , so i can do this easly.

The easiest way to weld the sideplates on is to get a piecr of GROUND FLAT STOCK approx. 1/4 " x 2" wide and cut it to approx 4" long - use this to C-clamp sideplates to receiver stubb -- this will hold everything square while U tac it up !!! i weld this with the TIG machine set at approx. 55AMPS - so U really are not puting alot of heat into one of these.
on the welding rod , I use ER70S6 to weld the sideplates on to the receiver stub , and use 4130 rod on the bearing surfaces-i.e. the upper rails & lower rails - but this stuff gets way to hard to weld the receiver stubbs together - i.e. the sideplates to the cut receiver stub , or the back cut receiver piece where the recoil spring goes --- if U build aYugo kit - U are gonna have to fabricate the bottom plate where the trigger guard rivits on , as i think this piece is trashed on the yugos , a piece flat stock approx. 80 thous. thick would work - you will have to weld build up the "pad" area that the mag catch part of trigger guard rivits to .. ===
ya gotta be patient doin yer first one of these -- the first one i did - i almost "lostit" and smashed the thing !!!---- GOOD LUCK ! IF u HAVE MORE QUESTIONS , IM YER GUY !!

NOW IF YER BRAIN IS NOT NUMB AFTER ALL THAT B.S. - GITTA WORK !!!!
 

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Thats interesting and thanks for writing it up. :smile:

I am itching to get started on mine. I think I will do it more or less along the lines you described, with adaptations to match the tools and such that I have available. The great thing about doing it this way is that the original markings are retained. The hard part, as you indicated, will be to get/keep everything lined up right so it doesnt look like an out of whack patch job. I want it to look good when I am done. So I have been taking my time getting started.

One question. What did you use for the ejector shark fin?
 

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ozzy the nuke said:
Thats interesting and thanks for writing it up. :smile:

I am itching to get started on mine. I think I will do it more or less along the lines you described, with adaptations to match the tools and such that I have available. The great thing about doing it this way is that the original markings are retained. The hard part, as you indicated, will be to get/keep everything lined up right so it doesnt look like an out of whack patch job. I want it to look good when I am done. So I have been taking my time getting started.

One question. What did you use for the ejector shark fin?
OZZ : sorry i left that part out - as there are alot of steps to make one of these , but what i do is before i weld anything to the cut receiver trunnion -i make the upper & lower rails - i cut a piece of the 4130 plate to make the lower rails - the left one with the shark fin , and first i weld a small bead on the top of plate for the upper rail - as 5/32 material is about .155 thick - and the correct dimension for the upper rails are approx. .175- so it is a small weld bead - after i get this upper rail milled in i weld the lower rails -i fuse weld these in place - but you may want to use filler rod on the bottom-- the left lower rail with the shark fin - it is critical that this lines up with the lower rail on the demilled trunnion - or bolt carrier will bind up on left lower rail ! -- after this you mill down left sideplate on the inside in F.C.G. area - so you can get hammer & trigger pins to take the shepards hook -or E-clips --- after this you will have -2 ready to weld on sideplates ..
 
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