Hi Guys,
First off, neat forum, glad to see there is a dedicated place for this sort of information!!!! Second, I am wondering if anyone has experiance with a TNW semi receiver kit? I have my parts kit and I have decided the way I will build my 34 is to use the TNW semi kit. My questions are: What sort of machning/welding will I need to do to complete the receiver 2) what additional parts do I need for a complete kit (I purchased an IMA MG34 kit), and 3) has anyone else gone this route in making their 34?? Thank you for any help or advice you can lend. Also, I have read quite a few posts about TNW parts wearing out, do they harden their parts at all?? Cheers!!
TNW semi-auto 34 reciever questions
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M20A1
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Colorado1919
- Stabshauptmann
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- Location: Colorado Springs CO
Welcome Jason. Don't know anything about the TNW 34s except that I want one. Just wanted to say welcome and this is the site to find out about them. By the way M20A1 is that the 75mm recoilless or the 3.5in rocket launcher?
Happiness is a WARM beltfed.
"I'm not as good as I once was, but I'm as good once as I always was." Toby Keith
Live to shoot, shoot to live.
Belt-feeders does not = bottom-feeders.
"I'm not as good as I once was, but I'm as good once as I always was." Toby Keith
Live to shoot, shoot to live.
Belt-feeders does not = bottom-feeders.
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Hole_Puncher
- Oberstabsgefreiter
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xanadu_trader
- Gefreiter
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- Joined: Fri Nov 04, 2005 7:28 pm
Jason,
My first post also, so bear with me and my typos…
I can answer a few of your questions. First, a little background – I ordered a TNW receiver kit in Aug 04, worked on it on/off for about 2 months at a friend’s machine shop. I would guess my total build time to be about 2 weeks. From experience, the first thing I would tell you is – YOU WILL NEED A GOOD MILLING MACHINE AND LATHE if you don’t want a lot of frustration.
The parts you will need to finish this receiver are the original receiver cams, the ejector plate, and the large interrupted threaded pin that attaches the barrel jacket to the receiver. If your demilled receiver has a torch cut through this pin (or the portion of the receiver behind it) you’ll need another. In addition to the receiver, you’ll have to modify your bolt and trigger to semi spec.
The kit comes with the rivets to attach the cams to the receiver, the parts needed to modify the bolt, a buffer to go between the semi bolt and the recoil spring, and the pieces needed to mod the trigger group. The receiver arrived in the white, wasn’t deburred, lots of flash still around the smaller pin holes. Threw it in an industrial tumbler for about 2 hours to get some of the rough edges out. After cleaning it off, tried fitting some parts to it - found out that this receiver is TIGHT! The bolt wouldn’t fit all the way through, and the charging handle would fit, but wouldn’t slide in it’s slot. Spent a lot of time using valve grinding compound and working the pieces in to make them fit/function. Don’t read this the wrong way – the receiver is NICE, it’s just that the tolerances are real close (most times within +/- .002, just enough to make the parts bind). The receiver doesn’t come with the large barrel jacket pin on the front, just a big hole (you can see it in the picture on TNW’s mg34 kit page). You’ll need to cut the pin off of your demilled receiver front, turn the back on a lathe to fit the TNW receiver, press it in and weld it in place (sounds easy, but there was a lot of lessons learned about getting aligned properly that I won’t get into here). The kit includes the screws necessary to attach the ejector plate, just use LOCTITE to make sure they don't back out. Riveting the cams was done with a blocking bar and a ball peen hammer. There were some other areas that needed a little fitting, but that was easily done using small files and a lot of patience.
Next, your bolt/carrier will have to be machined to semi spec. Instructions are provided. Unfortunately they were hand drawn and rather crude. It took a lot of calls to TNW for clarification on what had to be done. To their credit, Lance at TNW was very helpful, polite, and most of all patient with all of my questions. This is where you will need a milling machine – the steel on these bolts is HARD, nearly killed one of my end mills.
Finally, you’ll have to modify the trigger group. This was the easiest part. Most of the internals aren’t used, only the safety, trigger and trigger spring. You have to drill a small hole in the front of the trigger to attach a roller (included with the kit). This roller is what trips the sear in the semi. Again, this steel is HARD, and a milling machine came in real handy.
Have put about 350 – 400 rounds through it without any problems. Parts look OK, just normal wear.
Hth
Cliff T
My first post also, so bear with me and my typos…
I can answer a few of your questions. First, a little background – I ordered a TNW receiver kit in Aug 04, worked on it on/off for about 2 months at a friend’s machine shop. I would guess my total build time to be about 2 weeks. From experience, the first thing I would tell you is – YOU WILL NEED A GOOD MILLING MACHINE AND LATHE if you don’t want a lot of frustration.
The parts you will need to finish this receiver are the original receiver cams, the ejector plate, and the large interrupted threaded pin that attaches the barrel jacket to the receiver. If your demilled receiver has a torch cut through this pin (or the portion of the receiver behind it) you’ll need another. In addition to the receiver, you’ll have to modify your bolt and trigger to semi spec.
The kit comes with the rivets to attach the cams to the receiver, the parts needed to modify the bolt, a buffer to go between the semi bolt and the recoil spring, and the pieces needed to mod the trigger group. The receiver arrived in the white, wasn’t deburred, lots of flash still around the smaller pin holes. Threw it in an industrial tumbler for about 2 hours to get some of the rough edges out. After cleaning it off, tried fitting some parts to it - found out that this receiver is TIGHT! The bolt wouldn’t fit all the way through, and the charging handle would fit, but wouldn’t slide in it’s slot. Spent a lot of time using valve grinding compound and working the pieces in to make them fit/function. Don’t read this the wrong way – the receiver is NICE, it’s just that the tolerances are real close (most times within +/- .002, just enough to make the parts bind). The receiver doesn’t come with the large barrel jacket pin on the front, just a big hole (you can see it in the picture on TNW’s mg34 kit page). You’ll need to cut the pin off of your demilled receiver front, turn the back on a lathe to fit the TNW receiver, press it in and weld it in place (sounds easy, but there was a lot of lessons learned about getting aligned properly that I won’t get into here). The kit includes the screws necessary to attach the ejector plate, just use LOCTITE to make sure they don't back out. Riveting the cams was done with a blocking bar and a ball peen hammer. There were some other areas that needed a little fitting, but that was easily done using small files and a lot of patience.
Next, your bolt/carrier will have to be machined to semi spec. Instructions are provided. Unfortunately they were hand drawn and rather crude. It took a lot of calls to TNW for clarification on what had to be done. To their credit, Lance at TNW was very helpful, polite, and most of all patient with all of my questions. This is where you will need a milling machine – the steel on these bolts is HARD, nearly killed one of my end mills.
Finally, you’ll have to modify the trigger group. This was the easiest part. Most of the internals aren’t used, only the safety, trigger and trigger spring. You have to drill a small hole in the front of the trigger to attach a roller (included with the kit). This roller is what trips the sear in the semi. Again, this steel is HARD, and a milling machine came in real handy.
Have put about 350 – 400 rounds through it without any problems. Parts look OK, just normal wear.
Hth
Cliff T
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Intruder196
- Major
- Posts: 322
- Joined: Fri Apr 01, 2005 11:30 pm
- Location: North Carolina
My TNW 34 has some of the same characteristics. I bought a parts kit shortly after buying the gun and found that the dot 1944 barrel jacket from the kit was a much tighter fit than the one that came with the gun. Also the cocking handle from the kit would not fit at all. In the end I kept the barrel, feed tray, recoil spring from the parts kit and sold the rest off on Ebay.
I recently had the two screws that hold on the ejector plate break off. Lucky the screw holes were US Standard instead of metric. You will need to use loc tite on them or they will back out when firing.
I recently had the two screws that hold on the ejector plate break off. Lucky the screw holes were US Standard instead of metric. You will need to use loc tite on them or they will back out when firing.
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M20A1
Cliff,
Hi! Wow, thanks for the detailed response, that was EXACTLY what I was looking for!! I like challenging projects and it doesn't sound too bad at all. It is good to know that TNW was helpful as I'm sure I'll be calling them. I'd be interested to know more about the interupter thread at the front of the reciver and the allignment issues you had. I don't have a demilled receiver so I guess I'd better buy one to get that or purchase one from TNW if they have them. OR, does anyone on this site have a spare they would sell??? Also, are the rivet holes for the cams already in place on the receiver?
Thanks again for the information, I really appreciate it!!!!
Colorado1919,
M20A1 is for the 3.5" rocket launcher. First piece of ordnance I aquired in my collecting, neat little tank buster.
Intruder196,
Thanks for the info, Loctite is a good idea, did you use the red or blue??
Cheers to all!
Jason
Hi! Wow, thanks for the detailed response, that was EXACTLY what I was looking for!! I like challenging projects and it doesn't sound too bad at all. It is good to know that TNW was helpful as I'm sure I'll be calling them. I'd be interested to know more about the interupter thread at the front of the reciver and the allignment issues you had. I don't have a demilled receiver so I guess I'd better buy one to get that or purchase one from TNW if they have them. OR, does anyone on this site have a spare they would sell??? Also, are the rivet holes for the cams already in place on the receiver?
Thanks again for the information, I really appreciate it!!!!
Colorado1919,
M20A1 is for the 3.5" rocket launcher. First piece of ordnance I aquired in my collecting, neat little tank buster.
Intruder196,
Thanks for the info, Loctite is a good idea, did you use the red or blue??
Cheers to all!
Jason
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xanadu_trader
- Gefreiter
- Posts: 18
- Joined: Fri Nov 04, 2005 7:28 pm
Jason,
Did most of this over a year ago and have to jog the brain cells a little.
I use red loctite, works fine for me.
The receiver has holes drilled for the cam rivets – but they didn’t line up with the holes in my cams. Had to use a jeweler’s file set to correct the alignment before the rivets went in. Not a big problem, the steel of the receiver is relatively soft. The rivets provided are oversized (too long) and should be cut down a little before hammering.
Aligning the barrel jacket pin was another story. As mentioned before, the tolerances on the 34 are real tight – the alignment of the pin has to be precise, or the jacket won’t lock up correctly with the receiver. The pin has to be set at the correct depth as well as rotational alignment (the threads have to be facing out, EXACTLY from 12:00 to 6:00). I measured the distances on my demilled front before cutting the pin off. Getting the pin aligned correctly required clamping the receiver so it was level – not as easy as it sounds. Took a lot of bubble levels, t-squares, and old fashion eye balling to make sure it was true. Once I got the pin seated, I tried the jacket on. Everything seemed to line up – then I took the jacket off and my friend welded it in for me (I suck at welding). After, the sucker ALMOST closed – again the tolerances were off by a few thou (back to the grinding compound). In hindsight, I should have left the jacket ON when the pin was welded. My guess is the heat warped the pin out of alignment. Once I got them to fit I ground the weld smooth. One more thing, the notch on the receiver for the jacket latch had to be opened up a little for it to fit.
Another thing I remember is the retaining pin used to hold the stock latch is US, but the latch has a smaller metric hole. Had to drill out the hole on the latch for it to pivot correctly. Also, the retaining pin hole for the barrel return plunger was too large. This caused the retaining pin to bind against the plunger. Had to mill the flat on the plunger for it to operate correctly.
Cliff T
Did most of this over a year ago and have to jog the brain cells a little.
I use red loctite, works fine for me.
The receiver has holes drilled for the cam rivets – but they didn’t line up with the holes in my cams. Had to use a jeweler’s file set to correct the alignment before the rivets went in. Not a big problem, the steel of the receiver is relatively soft. The rivets provided are oversized (too long) and should be cut down a little before hammering.
Aligning the barrel jacket pin was another story. As mentioned before, the tolerances on the 34 are real tight – the alignment of the pin has to be precise, or the jacket won’t lock up correctly with the receiver. The pin has to be set at the correct depth as well as rotational alignment (the threads have to be facing out, EXACTLY from 12:00 to 6:00). I measured the distances on my demilled front before cutting the pin off. Getting the pin aligned correctly required clamping the receiver so it was level – not as easy as it sounds. Took a lot of bubble levels, t-squares, and old fashion eye balling to make sure it was true. Once I got the pin seated, I tried the jacket on. Everything seemed to line up – then I took the jacket off and my friend welded it in for me (I suck at welding). After, the sucker ALMOST closed – again the tolerances were off by a few thou (back to the grinding compound). In hindsight, I should have left the jacket ON when the pin was welded. My guess is the heat warped the pin out of alignment. Once I got them to fit I ground the weld smooth. One more thing, the notch on the receiver for the jacket latch had to be opened up a little for it to fit.
Another thing I remember is the retaining pin used to hold the stock latch is US, but the latch has a smaller metric hole. Had to drill out the hole on the latch for it to pivot correctly. Also, the retaining pin hole for the barrel return plunger was too large. This caused the retaining pin to bind against the plunger. Had to mill the flat on the plunger for it to operate correctly.
Cliff T
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Intruder196
- Major
- Posts: 322
- Joined: Fri Apr 01, 2005 11:30 pm
- Location: North Carolina
So far I have used only the blue Loctite. My fear is if these little screws break again, after the next 1000 rounds, will I be able to remove the broken ones if they are done with red? It was hard enough to remove the TNW installed screws after they broke and I dont know with certainty what they used if anything on them.
Guys - I will be posting a "photo essay" of the TNW seni MG34 receiver tonight or tomorrow.
Essentially the TNW receiver they sent me is probably one of the best examples of poor machining and quality control that I have ever seen.
1) It's dimensionally incorrect compared to original MG34 receiver sections that I have.
2) It's over machined in some areas - Too much metal has been removed.
3) Some features not machined
4) Excessive machining tooling marks and dings
5) Over polished (I guess to remove some dings) which softened some features making it look worn
I returned the first receiver they sent and then returned the replacement which came back yesterday.
The re-worked replacement receiver is somewhat better - They did complete some machining that was left off originally -
but basically it's a POS that will probably build into a weapon, just not a nice one.
The ONLY reason for keeping it is that TNW is the only game in town if you want a new, not re-weld, receiver.
Regards,
Orin
Essentially the TNW receiver they sent me is probably one of the best examples of poor machining and quality control that I have ever seen.
1) It's dimensionally incorrect compared to original MG34 receiver sections that I have.
2) It's over machined in some areas - Too much metal has been removed.
3) Some features not machined
4) Excessive machining tooling marks and dings
5) Over polished (I guess to remove some dings) which softened some features making it look worn
I returned the first receiver they sent and then returned the replacement which came back yesterday.
The re-worked replacement receiver is somewhat better - They did complete some machining that was left off originally -
but basically it's a POS that will probably build into a weapon, just not a nice one.
The ONLY reason for keeping it is that TNW is the only game in town if you want a new, not re-weld, receiver.
Regards,
Orin
"It is well that war is so terrible -- lest we should grow too fond of it." Gen. R.E. Lee CSA
Skype ID: ACE1100
Skype ID: ACE1100
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xanadu_trader
- Gefreiter
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- Joined: Fri Nov 04, 2005 7:28 pm
Orin,
Wow - sounds like their QC really went down hill since I bought mine. The one I got required a lot of fitting, but mostly to remove burrs or small raised areas. There were a lot of tool marks and small dings, but most came out when I sandblasted it prior to finishing. Will be very interested in seeing what they sent you...
Cliff T
Wow - sounds like their QC really went down hill since I bought mine. The one I got required a lot of fitting, but mostly to remove burrs or small raised areas. There were a lot of tool marks and small dings, but most came out when I sandblasted it prior to finishing. Will be very interested in seeing what they sent you...
Cliff T
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M20A1
Hi!,
Thanks for all of the great info guys!! If the TNW receivers are junk then perhaps I should do a reweld? I only have my parts kit and have not committed to anything quite yet. If a weld jig comes out then I guess I might go that route, sounds a wee bit cheaper. On the other hand, while I am handy I'm no John Browning when it comes to firearms design so I'll keep my eyes peeled for someone more skilled than I posting a tutorial.
Orin, I'd love to see the pics of your receiver, can you point out the mistakes and areas left incomplete so I know what to look for (I don't have much experiance with German MGs, I'm a 1919A4 guy). Once again, thanks for all of the great info.
Cliff, thanks for detailing your trails and tribulations with the TNW receiver. Still sounds doable as long a they send a good example of one.
Cheers!!!!
Jason
Thanks for all of the great info guys!! If the TNW receivers are junk then perhaps I should do a reweld? I only have my parts kit and have not committed to anything quite yet. If a weld jig comes out then I guess I might go that route, sounds a wee bit cheaper. On the other hand, while I am handy I'm no John Browning when it comes to firearms design so I'll keep my eyes peeled for someone more skilled than I posting a tutorial.
Orin, I'd love to see the pics of your receiver, can you point out the mistakes and areas left incomplete so I know what to look for (I don't have much experiance with German MGs, I'm a 1919A4 guy). Once again, thanks for all of the great info.
Cliff, thanks for detailing your trails and tribulations with the TNW receiver. Still sounds doable as long a they send a good example of one.
Cheers!!!!
Jason
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Reichpapers
- Brigadegeneral
- Posts: 678
- Joined: Thu Mar 17, 2005 8:55 pm
- Location: Reading, PA
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M20A1
Hi!,
I know IMA has cut 34 receivers right now but what do you guys think is the best source for cut receivers?? I'm still bouncing back and forth between the TNW and a reweld. A couple of receivers and a TIG welder would still be 1/2 the cost of the TNW piece (price as of 2 weeks ago $1899). What do you think Orin, was it worth the hassel? Cheers! Jason
I know IMA has cut 34 receivers right now but what do you guys think is the best source for cut receivers?? I'm still bouncing back and forth between the TNW and a reweld. A couple of receivers and a TIG welder would still be 1/2 the cost of the TNW piece (price as of 2 weeks ago $1899). What do you think Orin, was it worth the hassel? Cheers! Jason
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Reichpapers
- Brigadegeneral
- Posts: 678
- Joined: Thu Mar 17, 2005 8:55 pm
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The IMA receivers will not be enough to complete the job...where the demills may have enough overlap if you buy a few..you still need the complete front section with the cams and stud. BRP sells the front receiver section with their kits....someone else used to sell just the front section, but I forgot who. I bought 2 FAC receivers and 2 IMA receivers...I managed just enough for two receivers...
It's better to be silent and considered a fool, than to speak and remove all doubt.
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M20A1
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Farmer Mike
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M20A1
Thanks guys! I received a kit from IMA, good solid kit, a definate aresenal refinish as the shroud markings have been ground off, although nicely done, and the bluing on the whole set is right about 99% I noticed that TNW is finished with their Gov't contracts so perhaps their quality control will shift back up a notch while they focus on MG 34's etc, instead of Mk 19's for the troops. Cheers! Jason