temp installing the rails looks as if it will help from side to side on the rear of the reciever but what about the length? could it be set just by the top cover or is there something critical for the internals that I am missing.
also the front of the reciever really has me puzzled
When I started rewelding mine. I used fixed pieces of the parts kit to set most spacing. Rails/topcover for the rear section, trunnion for the center, front barrel bearing w/barrel installed for the front. Tack weld on corners and remove parts. Make sure you clamp tightly to a perfectly flat table and weld slowly to reduce warping. About the only way to check rotational and lateral warpage is eyeball and maybe a steel straight edge. My first weld( a dummy) built on a 4 cut allegheny reciever actually came out really straight only eyeballing it, lucky me. This worked for me, hope it helps you.
On the front cut using the trunnion works well especially if you have the barrel door and latch installed on your kit because the barrel door locks to the trunnion on the right side this gives you another spacing tool. At least you are not trying to reweld one of the Allegheny kits, that cut barrel bushing was a b@$ch to get straight. If you have a angola kit you can actually use the front bipod slot to space, just measure the rear bipod slot and the front one should be the same. remember to cut your grip stick hole larger and install your FA bolt block before rewelding completly or you will be in violation of NFA rules. No No
Does anyone else have a method? I have seen a blueprint of an mg42 that's of poor quality..Does anyone have a real scale blueprint. I am afraid of starting up my project and not getting this reciever right the first time..any books or manuals recommended..
Stife,
I've been wondering how I'll get mine aligned before the weld also.
the others mentioned the bipod area (since this is where Dan's cuts run through), and making that
slot identical in length to the rearward bipod slot (near barrel ltch door). Good idea.
Also, on top of that, one could temporarily install the barrel, slip the front cut on with booster assembly
installed, then run a Dowel rod just snug enough--soft wood- into the barrel from the flash hider. This would get you
real close before clamping it down . The flash hider catch could give you an additional eyeballing, as to how/if the
two cuts are setting at a pitch.
I plan on doing this, and CLAMPING heavy, then taking the overall measurement from front to rear.
I will remove barrel, and booster assembly, and tack.... re-install, and check.... remove, and go for it.
Measurements from Trunnion slot forward would be nice for last minute check. The full length is available
somewhere here in the forum--- I believe Jason started the thread on that last month.
OAL (over all length is 37 11/16 inches long from rear of recv'r with buffer/stock REMOVED to the end of barrel jacket threads (muzzle cone/flashider/booster REMOVED)
Karb, thanks for that..I've more or less gone about it that way. I'm going to cleanup the torched ends to tomorrow and start lining up and measuring..I bought an mg34 last week from BRP and by comparison I believe that the tolerances are somewhat forgiving. A true factory blueprint helps but I think The method you are using should suffice...I promise to buy a dig camera and learn to post...Over and Out.
I hope that I dont get in to much trouble for saying this but when I re-welded I had no idea what lenght the finished reciever was supose to be.
I started with the trunion cut because once the trunion was slipped over the reciever pieces it set the spacing. then I set the tail of the reciever with the top cover, just make sure you dont get the rear to low because the top of the bolt just clears. the front was set by a combination of bbl/booster fit, and the length of the area the bipod fits into.
I'm sure there are better ways to do this but it worked for me.
HI TO ALL,
WHEN I WELDED THE RECEIVER TOGETHER I MADE UP A SET UP TOOL. THIS BAR STOCK WAS MACHINED TO SLIDE DOWN THE RAILS ON A TIGHT FIT. THE BAR WAS CUT LIKE A 12 INCH 950 BOLT. WITH RAILS NUTTED INTO PLACE I INSERTED THE SETUP BAR, AND THE PARTS WERE READY TO TACK WELD. THIS BAR WILL EVEN FIT INTO THE BARREL EXTENTION. REMEMBER THAT THE 42 WAS MENT TO BE SLOPPY ON ITS FITTING. IT WILL FUNCTION WELL WITH A LITTLE WARPAGE AT THE TRUNNION AREA. THESE GUNS ARN'T THAT SMART, SO DON'T OVER DO IT. THINK OF THE DIFFERENCE BETWEEN AN AR-15 VS. AN AK-47. I ALSO USED EYE-BALLING, BUT MOST OF ALL A STRING LINE FROM THE FRONT TO BACK THROUGH THE COOLING HOLES AND THEN ALONG THE RAIL HOLES. WHEN TACKED, CHECK WITH THE STRING, ALSO WITH THE BARREL INSTALLED AND DOWN THE RAIL HOLES. THE 42 BOLT HAS A .050/.070 SIDEWAYS SLOPPY FIT INSIDE THE RAILS. UP AND DOWN IS LESS. TAKE YOUR TIME, THINK AHEAD, TACK WELD SO THAT YOU CAN HACKSAW APART, IF NEEDED. YOU MAY ALSO NEED TO FIT THE TOP COVER TO LOCK DOWN AT THE REAR OF THE RECEIVER DUE TO MISMATCHED PARTS OR JUST PLAIN SHRINKAGE FROM WELDING. I HAD TO REMOVE ABOUT A 1/16 OF MATERAL FOR IT TO LATCH. THE RECEIVER OVERALL LENGTH IS 48.2 INCHES ( 1225mm ), BUT ONE SHOULD BE ABLE TO ASSEMBLE RECEIVER WITH ITS PARTS AS A HELPFULL SETUP TOOL.
CHECK OUT THE LATEST SHOTGUN NEWS TREASURY ISSUE ON THE NEWS STANDS, IT HAS A GOOD WRITE UP ON THE 42.
GOOD LUCK WITH ALL YOUR BUILDS
WEASEL
After examinining my kit I decided to make a set of plates to use to set the receiver
square and to proper length. I am going to bolt them to where the rails go and
clamp the front and rear sections on to them after aligning them.
I will post some pics when they are done.
It occured to me that if the receiver length, at least between the MG42/3 Ground tripod lugs is not correct, it will not lock into the mount. At least with my 1919 adapter, the fit is rather tight, and doesn't appear that it would lock in if so much as 1/4" off. So whereas the firearm may have sufficient tolerences in certain receiver sections such that it would still function OK, it may not be the correct length. Besides, it would be a pain to have a functional 42 that won't drop onto a tripod.
I used pirate's unistrut and bolts idea with a 1/4"all thread run through (buffer removed, barrel installed).
Used soft copper pipe to cover the barrel end at the weld. Broke lighter copper for inside the camming piece and at the rear.
Welded a bolt in to block the fa bolt and cut the grip area.
They tell me women don't remember the pain of childbirth after the baby's here. These are similar.
This worked for me, hope it helps you.
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