New m53 build

[roadrunner]

Hi guys, First I just want to say I really appreciate the professionalism of your site. Not the normal b.s. I've seen elsewhere. I am in the process of building a S.A. m53. I purchased a really nice parts kit. Cut in the rear of the D-holes
Having 25+ years in the machinist/toolmaker trade I Don't see it as too challenging.....But! I am not too proud to take advise. My main concern is whether to save as much of the shroud and save my forward rail and recuperator holes for reference. Or cut closer to the camming piece utilizing my entire BRP reciever section. My autobody experience says save as much original metal as you can but having my weld butts in the rails makes me wonder. hmmmm.
By the way I will be using an expandable internal copper alignment jig during tig welding. Thank guys. Any input is appreciated.

[crash520]

Welcome,

For my two cents worth, save as much as you can of the original, having those existing holes are an invluable ref point, in fact it would be great if you could document them and post them from the back of the cam box wind back..
Im sure we would all like to see your expandable coper alignment item and progress pic's.

enjoy the project, we all do

V/R
Crash

[roadrunner]

Thanks Crash for the reply. I've been leaning the same way. Save as much shroud as possible. I'll document all the measurements as I go and share it all. Today I picked up my BRP rear section,rails etc. and like Tinkerbell was a bit dissapointed that the ratchet plate was already spot welded on. let alone crooked by almost .100". I previously passed on those particular ones but oh well. Just spot mill the welds and remove. I'm pretty excited about this project and enjoy reading all the other posts on the subject. Hope to contribute to the cause in the future.

[waffendude]

welcome to the site
i agree with both of you guys---keep as much of the org as possible--and work from there--i did not see in your previous post--if you had a frt bearing---if the kit you bought has one intact---great---but most do not--and the frt bearing will need to indexed and welded to the frt shrould

thats a shame that brp welded the ratchet plate to the rear receiver.
good luck and keep us posted
waffen

[crash520]

Roadrunner,
could you fill in the red box's on the image or supply the measurements off you Mg53 for us please.




im out of time and have to go, i will try over the weekend as well to get the pic up

[roadrunner]

Crash, Heres the measurements. Close as I can get with my mitutoyo calipers. Using edge of cam window to holes edge then adding radius. Hope it helps. Hey Waffendude. thanks for the welcome. Yeah my threads were cut some. Already removed bushing. kept all of the reduced shroud diameter intact. Might try the shroud window insertion method I read about. Still pondering. Have the BRP original style bushing. Later guys

[crash520]

Thanks RR
Thats awesome, will let you know how they compare over the weekend.

C

[roadrunner]

Well, after lots of thought made the decision to cut shroud and insert bushing. I know some dont like this method but I think it has lots of merit for its alignment and control of setting bushing depth. I am confident in my tig abilitys and can make it dissappear easily. Will cut back the reduced area another 1/8" and turn a split bushing to cover the front bushing shoulder to better replicate the original. It may look/sound like alot of fuss when you could just grind off the shroud and hammer it in like I've seen done but I'm a bit anal about appearance and quality. Let me know if i'm all wet.

[crash520]

VERY nice.

[roadrunner]

Finally got back on my project today. Setup and milled charging handle groove and opening. Still have to mill ratchet plate and charging handle. Cant find my 3/32 woodruff key cutter. C/H is bent slightly so needs adjustment but alignment looks good. Decided to do this before welding halves. Glad I did too. Need to ensure C/H rides nice and low in corner. Radius looks close so shouldn't need too much fitting. Later guys. RR.

[jcmg42]

[crash520]

Nice work RR
im about ready to do the same but have a trip to Austria then back for 8 days then Camp Perry for two weeks so it'll be late August before I get back to the bench

[roadrunner]

Hey Crash, Enjoy your time in Austria. Wish I had some trips across the pond but mainly just an occasional trip to Pearl or Norfolk . Did I start this post by saying not too challenging ? These length discrepancies are driving me nuts. Bend profiles on these stampings do not jive with the BRP prints. Just going one step at a time now. Measuring from front to back helps. Been gathering data from everywhere. Hard trusting any one source. Best I can do is get a good understanding of each parts relationship to another and custom fit everything. Good travels RR

[crash520]

RR,
Having your rec cut where it was is a huge advantage,mine, like many had been cut right through the cam box stops. All of the drawings BRP's and others show the dim"s from the back forward to about the 'D' holes for the rails but forward of there has been a little bit of a guess, you providing them helped certainly me out a lot. From there, so long as you get the grip stick location in the right spot your set, the 382mm from cam box to back that people mention is a correct length for the rear. With those two your good to go with everything else pretty much.

V/R
C

[www.Prussia.us]

You guys are doing outstanding, chances are these questions are in the minds of many that contemplate this build.

I did not realize the BRP stampings were so lacking for guidance in the cam area.

Has anyone ever checked back to see if ColdSteel got their act together?
http://www.coldsteelsolutionsincorporat ... nc_003.htm

They had a so-called 80% receiver for around $300 the first batch were rough but viable, then rumor had it they were out of spec (3-4 years ago), but their website is still up. If he is back in spec it may be an option for those that are not the best welders, as the box is all ready put together. But be aware, the ones sold out of spec were really a mess.

[roadrunner]

I think I've got a handle on these dimensions now. When I milled out the c/h opening. I used the brp side view prints. Reached 8.110" on my mills dro and hadn't event reached the edge yet. Had to go to 8.325" before it cleaned up. This made me think I had too much length on the rear. Not even. 10.4" to ejection port was right in the ballpark as well as length of top buffer slope end and top cover slope end. uh oh Worked out the 382mm dim. going back from cam edge and good. Then went back to brp prints and found bottom view calls out 8.310" to forward edge of opening. So I'm .015" over the bottom view dim. Then I remembered oakrodent build measured 10mm end of charging handle to end of receiver. Tip was flush to opening to slightly in. Mine is 10mm/ .393" pressed tight to edge. Hope I'm good. Thanks for the 382 dim. Crash and the encouragement Prussian
I think this things got potential.

[crash520]

RR,
just to confirm for you, this is what was posted by several members and I also confirmed this on an original 42.

"According to the MG42 armorer's manual: The distance from the rear edge of the receiver (buttstock end, with stock and base piece removed) to the rear of the rectangular openings where the ramps of the cam piece stick into the receiver = 382 mm. The spec says it can be short by 0.2 mm."

C

[crash520]

Oh, one more thing, one of my BRP rear sections I had to cut about 1mm off, the other will be about 5mm (I think from memory)

C

[roadrunner]

You know, lengths has been my only hangup with this build. I feel pretty lame for not finding the other reference to the 8.310" dim. sooner. BRP might consider changing their prints at least so side and bottom views share the same numbers. Even so, my fault. Was planning on skim milling the rear after welding. Squaring and prep for boring buffer grooves. So I will remove the .015" then. If this was simple everyone would do it and I wouldn't enjoy it.

[www.Prussia.us]

RR, you are quick to accept responsibility which is admiral but BRP should do a better job sorting it out. I have nothing but praise for Brian, real nice guy, and he has helped me out quite a bit over the years, nonetheless he should not leave you guys flying blind. Anyway, just think how much faster the second one will be to build