New m53 build

[marknct]

I'll take a look at the pdf tonite.
RR
We always scream about about other people documentation right? Then it comes time to work from one of your own drawings and er.... ummm... something missing here.
To make myself nuts i installed 53 rails in the stub as is with screws and the bolt assy slides smoothly. Grrrr, need to play around some more and figure out what is really happening.

[marknct]

BRP drawing calls for 1.312 width in top of rcvr under feed tray, it looks like they were about 1.25" originally. Did you open the Yugo stub or stop at 1.25 for the slot?

[roadrunner]

Mark, all 3 of my shrouds measure out at 1.25" + . 005-.010 and that's where I blended to. Did not see any need to change original dimension. Am very interested to see your weld jig setup idea. Keep it going. RR

[roadrunner]

alighnment bar.jpg (25.73 KiB) Viewed 10523 times

Mounted Ratchet plate using alignment bar I made. Added .010" to C/H height and clamped tight while plug welding. Had to drive it out with wood rod and ended up with .007" clearance. Rides real smooth and not wobbly.
Pulling back C/H end clears receiver by .020" and pops up. Made insert and push off bar attachment for ratchet plate using Oakrodent's methods again. Gotta give him major props. for his tutorial.It has solutions not covered anywhere else. So close now. Just a little tig and file and I can almost smell the powder smoke. RR

[marknct]

RR
Backing up a bit. Did you trim the front of your mg3 rails where they would contact the CS? The alignment tabs in the center of the rail track are really close to the rivets on the new ones. I noticed on the used rails they grind that edge back to the tab.

[roadrunner]

Marknct, Yes, I did trim them. After finishing D-holes to spec. Inserted rail and scribed rail at cam section opening. Removed rail and cuttoff proud. Then filed flush to rear of opening. Had to file fit a bit more to insert cam piece but probably only .005" clearance est. Did all filing out of receiver as cam piece fits real nice and didn't want to change receiver opening. And yes, they are flush on front with center tab now. RR

[marknct]

I took another look at Oak rodents pic and he seems to have more space between the rail and CS. It looks like the space the kit pieces have. I agree with your spacing of .005, I don't know why the gap should be so big. Unless they worry about heat expansion and the pieces buckling against each other? I would think zero clearance would be the goal to help support the extensions if the barrel hits it in recoil. We need some saw cut or original FA people to look at theirs and comment.

[crash520]

The mating surface of my CS's show signs of the rails had been touching the tabs when originally built as the blueing is worn off a little, I'll take photos on the weekend if anyone wants me to.
VR
C

[marknct]

Crash
I looked at a few CS today and came to the same conclusion as you. I can't see the point of the D cut if it wasn't to set the distance over the long term. A matching set of CS even showed signs of fretting from the rail. Looking close I can see where the barrel was hammering the front of the cam so hard it left an indent.
Looking at the barrel stop leads me to the same conclusion. The D is there to oppose the barrel coming home and take the shear off the rivets.
When i look at the leading rail edge with a 10x loupe it looks like they were profile milled originally. Then it looks like they used a rotary grinding wheel to tune it in.
Probably a good idea to finish fit the rails after the section welding and riveting the CS.

[oakrodent]

First of all this is a very nice build, sorry I have followed it earlier. I'm not sure why it looks like a large space between them. You do need a little space, 0.5 - 1mm. Again, it looks like a very nice build. Here is one of mine in action:
http://mg42.us/viewtopic.php?f=13&t=10465

[roadrunner]

Wow! great video. Hope to be there real soon. Got feeding, ejection and trigger all to function real smooth. Just need to finish weld ar adapter to gripstick. Tacked it for fitting in case it needed moving. P.S. your Schwartzlose build is about the coolest thing I've ever seen. Love the camo. too RR

[oakrodent]

Once you finish the first one, you'll be hooked! Once you get the small bugs worked out they run like a top. Thanks for the comment on the Schwartzlose. Once my mill is set up I can remake the last part then that pig should be running like a top also.

[roadrunner]

Got it all together today and test fired. All went well aside from some finger jarring trigger slap. Afterword compared it to my ar15's trigger and it has way too much overtravel. Need to make a trigger stop. Rear of trigger and dissconnector is going too high and taking a major whack from the hammer. Other than that, all is good. Will strip and refinish it after it is 100% RR

[crash520]

Sounds like its working perfectly!!!!!

[roadrunner]

Problem solved. Couldn't leave it alone in that condition. Bottom of bolt had serious drag marks on it. Smoothed it all out and polished. Took a hair off of trigger stop screw and off to the range again. Great single shot function now and no trigger slap.

[bostonscott05]

road runner, iv read your whole build today and I must say that I hope my build comes out like yours. Im working with a less than desirable receiver and have a ton of work to do. I'm hoping I can get you to take a look at my threads listed in the MG42 general discussion under PLEASE HELP!!! Yugo build....any and all help would be greatly appreciated!!!

[webmaverick]

Wow - very good info. Ive been messing around with a MG42 build for about 6 months off an on - got me motivated again!

[42rocker]

It is a very good thread. Good Work I might add. As said before WAY TO GO!!

Later 42rocker

[roadrunner]

Thanks Rocker, and thanks for all the input along the way. Its been a fun project. Hope to get on to my other ones sometime soon but house plans rule this summer out. Take care. RR

[42rocker]

roadrunner
Like your thread so much downloaded and cleaned it up some (took out posts and other stuff) and redid it in a word doc.

Later 42rocker

mg42 build by roadrunner 2013.docx

(1.59 MiB) Downloaded 294 times