Brother, really enjoyed this video, I have two kits, one F.M.P./G3 and one Cetme~C as well. And you shown this wonderful video. I can't do anything now. Physically/health wise, but as soon as I heal. Hell yes.!, thanknyou again for sharing this to us.! Your jig, your ideas, your bends are perfect
Awesome jig. We ended up renting one, because there was no way we could’ve fab’d one on our own when we started. It had a straightening/sizing mandrel made from a section of bolt carrier that you pulled through the folded receiver with threaded rod. This was absolutely crucial for our receivers, it formed them exactly to size internally, because without running the mandrel, our bolts wouldn’t drop through at first. Also, we didn’t weld the receiver section at the trunion yet because we found out we needed th extra flex to get the cocking tube in before the trunion. We’ll do that last weld after headspace is set and everything is ready to go together one last time. It feels we’re doing dry-fitting on stuff a hundred times before a weld. The semiauto shelf weldment was a prefect example of that. The included ones needed many thousandth’s clearancing to fit around the bump at the back of the magwell. I envy your TIG capability - I’m running flux core like a bum, lolz. Can’t wait for the next video!
depending on what manufacturer of flat you used, you may need more than just a section of bolt to get it into spec, there are some outside pieces what will push the rails inward into a mandrel that you force into the receiver the PTR flats that hkparts sells are good to go after bending and welding, as long as the bolt drops freely, but the flats sold by robertrtg are not fully formed and require a internal and external mandrel to get into spec
We used the RTG flats…After the forming mandrel was driven through a bunch of times, the receivers needed some ocassional smacking on the outsides/rails while the BC was inside to get everything where it was supposed to be for the bolt to drop through as the flat was fully closed and then welded at the rear and the magwell. So yeah, I concur with what you’re saying. Next time I think we’ll try HKparts flats. @@JohnSmith-tj5se
Thank you. This is the best and most simple jig that isn't janky that I've seen so far. I'm gonna try this. I'm gonna try doing an hk21 build. I've done a mp5, mp5k, and a mp5sd and gotten better each time. I'm hoping to being close to factory quality with this next build and I'm positive this'll do better than conduit.
i'm interested in some details about the welding aspect of this. the consumables in particular. and your welder settings. i'm building some of these and i'm learning tig welding as i go. what size and color of tungsten? details on the filler rod used. argon gas flow meter settings? any details you could provide would be greatly appreciated!
I use 3/32 tartan G tig rod, welder just set to max current of like 150a and I just pedal it to feel. I use 3/32 blue tungsten for most everything. Argon flow is related solely to your cup size. 2-2.5x (min-max) your cup size. I use a #8 gas lens for most work. Cup size dictates how far you can stick tungsten out too. The bigger the cup the more gas flow required though!
What type of milling machine is that? Love the videos by the way. I trying to learn as much as possible about parts kits as i want to work on my own someday! Great video!
Refreshing to see a non believer. Most people believe in the shaving cream rule "the more you use , the better it works " instead of the brylcreem rule " a little dab will do ya "
All that is not important, the only important dimension is the space between the rails and the mandrel size. I don’t have it written down anymore but I explain the dims somewhere in the video.
there are 2 flats available, these ones are not fully formed, the front of the mag well has too large of a radius which means the mags do not engage with the step on the trunnion, the mags cannot go forward enough too engage the locking lip on the trunnion also, the rails are not fully formed which means the bolt will not drop freely unless you spread the receiver too far apart, the distance between the rails should be 25.5mm, if they are too far apart there will be a step where the rail meets the trunnion, this step means the gun will be unreliable and wear itself out quickly, the rails need to be flush where they meet up to the opening for the bolt in the trunnion or there will be issues i can give you a lot more info on this build if you want it
You're referring to the PTR flat and flats that RTG has right? How can you tell which one you have? I've got a couple that I bought a long time ago and I can't remeber where I got them from
Best CETME build video on UA-cam!
Brother, really enjoyed this video, I have two kits, one F.M.P./G3 and one Cetme~C as well. And you shown this wonderful video. I can't do anything now. Physically/health wise, but as soon as I heal. Hell yes.!, thanknyou again for sharing this to us.! Your jig, your ideas, your bends are perfect
Awesome jig. We ended up renting one, because there was no way we could’ve fab’d one on our own when we started. It had a straightening/sizing mandrel made from a section of bolt carrier that you pulled through the folded receiver with threaded rod. This was absolutely crucial for our receivers, it formed them exactly to size internally, because without running the mandrel, our bolts wouldn’t drop through at first. Also, we didn’t weld the receiver section at the trunion yet because we found out we needed th extra flex to get the cocking tube in before the trunion. We’ll do that last weld after headspace is set and everything is ready to go together one last time. It feels we’re doing dry-fitting on stuff a hundred times before a weld. The semiauto shelf weldment was a prefect example of that. The included ones needed many thousandth’s clearancing to fit around the bump at the back of the magwell. I envy your TIG capability - I’m running flux core like a bum, lolz. Can’t wait for the next video!
depending on what manufacturer of flat you used, you may need more than just a section of bolt to get it into spec, there are some outside pieces what will push the rails inward into a mandrel that you force into the receiver
the PTR flats that hkparts sells are good to go after bending and welding, as long as the bolt drops freely, but the flats sold by robertrtg are not fully formed and require a internal and external mandrel to get into spec
We used the RTG flats…After the forming mandrel was driven through a bunch of times, the receivers needed some ocassional smacking on the outsides/rails while the BC was inside to get everything where it was supposed to be for the bolt to drop through as the flat was fully closed and then welded at the rear and the magwell. So yeah, I concur with what you’re saying. Next time I think we’ll try HKparts flats. @@JohnSmith-tj5se
Keep us updated dude. I’m about to buy a kit and build it.
Will do! I’m pretty much done now, just need to get the video made… that takes almost as long as the build itself!
Just what I’ve been looking for - thanks! My CETME kit is enroute so your videos will be invaluable! Thanks.
Very nice job on the jig.
Really nice job, great craftsman. Thanks
Thank you very much!
Thank you. This is the best and most simple jig that isn't janky that I've seen so far. I'm gonna try this. I'm gonna try doing an hk21 build. I've done a mp5, mp5k, and a mp5sd and gotten better each time. I'm hoping to being close to factory quality with this next build and I'm positive this'll do better than conduit.
wow you made that look easy. I have always wanted to build my own firearm lie a G3/Cetme. All I need now is "lotsa money" then I can do all of that!
nice that jig looks way better than the unistrut i used on my build
i'm interested in some details about the welding aspect of this. the consumables in particular. and your welder settings. i'm building some of these and i'm learning tig welding as i go. what size and color of tungsten? details on the filler rod used. argon gas flow meter settings? any details you could provide would be greatly appreciated!
I use 3/32 tartan G tig rod, welder just set to max current of like 150a and I just pedal it to feel. I use 3/32 blue tungsten for most everything. Argon flow is related solely to your cup size. 2-2.5x (min-max) your cup size. I use a #8 gas lens for most work. Cup size dictates how far you can stick tungsten out too. The bigger the cup the more gas flow required though!
@@JPMachine thanks so much for the info brother!
Great video! Is the next video in the build series coming soon?
Check it out now! All the rest of the videos are out!
Is there another place I can find the videos on bolt gap and welding? Did UA-cam delete them?
Yep they did. Look for my name on rumble!
@ found you ty, you do great work btw
What type of milling machine is that? Love the videos by the way. I trying to learn as much as possible about parts kits as i want to work on my own someday! Great video!
It’s a LMS 3990 mini mill, works great for what it is within its limitation
@@JPMachine thanks! Love the videos!
Hi.why does the push bar have the .75 flats? Other jigs are all round
Saw that dimension online, the other thing to use is a 20mm round bar instead of what I used
@JPMachine 20mm that's smaller than yours, right?
@joeygabriele71 just a touch yep, but that’s the real dimension if I remember correctly
@@JPMachine thank you
Can an hk91 locking piece be used in a cetme c 308? If not, why not?
Not sure honestly!
Good video.
Thank you
Refreshing to see a non believer. Most people believe in the shaving cream rule "the more you use , the better it works " instead of the brylcreem rule " a little dab will do ya "
Any chance of getting the material dimensions for your jig? Size and length of square tubing and what was the base size?
All that is not important, the only important dimension is the space between the rails and the mandrel size. I don’t have it written down anymore but I explain the dims somewhere in the video.
Was that 1" square tube? I tried a unistrut jig, and the unstrut was flexing out making the receiver skewed. Looking for a different method.
I think it’s 1.25”. I had it laying around from years ago. It works great!
there are 2 flats available, these ones are not fully formed, the front of the mag well has too large of a radius which means the mags do not engage with the step on the trunnion, the mags cannot go forward enough too engage the locking lip on the trunnion
also, the rails are not fully formed which means the bolt will not drop freely unless you spread the receiver too far apart, the distance between the rails should be 25.5mm, if they are too far apart there will be a step where the rail meets the trunnion, this step means the gun will be unreliable and wear itself out quickly, the rails need to be flush where they meet up to the opening for the bolt in the trunnion or there will be issues
i can give you a lot more info on this build if you want it
You're referring to the PTR flat and flats that RTG has right? How can you tell which one you have? I've got a couple that I bought a long time ago and I can't remeber where I got them from
@@garrettblankartz8102 the RTG flats have the holes for the buttstock pins pre-cut, the PTR flats do not
@@JohnSmith-tj5se Thank you
Great explanation , might try to build my own jig. Did you get away from mig welding for any reason ? Can’t wait for next video. !
Tig is just so much more controllable. I let a friend borrow my mig a few months ago to let him learn and I haven’t needed it at all!
What welding machine do you use if you don't mind my asking?
It’s an alphatig 203xi! Been using it about a year and have no complaints!
I have a 3d printed one and the main issue people run into sometimes is over bending.
Hi I'm interested in getting a jig could you make me one ?
I don’t have plans on making more, but I am loaning this one out if you wanted to get on the list. Email me at jpmachine607@gmail.con
@@JPMachine perfect thank you brother
I really wish I had seen this before trying myself. I used an old piece of galvanized pipe, a hammer, hammer and a vise.
Disqualified