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Posted: 2/4/2010 8:16:23 AM EDT
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SO awhile ago In posed the want to build a HK53, Well I have been looking around and kind of impulse bought a weld kit, so now dose any body have palns or would be willing to loan, lease borrow a jig or if anyone know the specific diameter or has plans for a jig tjat would be awesome. Also any suggestions on the nxt major part to buy
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By "weld kit" do you mean the parts kit (torched/cut H&K firearm), or just the small receiver pieces that are needed during assembly?
Rim Country Manufacturing makes HK 53 barrels and trunnions. (I've not done business with them myself, but have heard good things about them) I'm planning to build an HK93 sometime in the future. (No SBR's in NY, unfortunately) I'll be getting a HK93 parts kit, US receiver flat, US trunnion, US barrel and 3 US trigger parts (no muzzle device). Or maybe a US cocking handle and reuse the old trunnion, don't know yet. I believe the 6 parts is all I'll need for 922(r) but will double check that before building. Last I heard, SBR's were exempt from that 922(r) nonsense, so you I don't think you'll need to worry about that if you build on a form 1. Do some googling on "HK semi shelf" and "clipped and pinned" and read as much as you can on that. I think that the only flats available at this time are of Todd Bailey manufacture, I'm still reading and figuring out if his flats will work alright or not. It looks like I will need to make a tool to press the top ribs into the receiver should I use one of those flats. (They aren't absolutely necessary, but I'll press them in if my flat doesn't have them) The HK53 is just a shortened 93, so you could probably grab an HK93 parts kit and make use of a lot of those parts. I don't know if that will work out cost wise to being cheaper than getting parts individually or not, so you'll need to check that. I believe that the 53 bolt carrier is shorter than the 93, and the cocking tube & support may be different (not sure). hkparts.net is a good source for parts. The prices may not be the best, but it's easy to order and Adam ships the stuff pretty quick. You can also check robertrtg and hkspecialist for parts. I have not ordered from Gordon at hkspecialist, but I haven't heard anything bad about him. robertrtg is not up to speed with their ordering system, so you don't get an email when it ships or tracking info, but so far I've received everything I've ordered. Adam and Gordon both appear to have HK53 carriers available. (but, you may be able to shorten an HK93 carrier. I haven't seen either of these carriers at this point so I'm speculating on that.) As for the jig: It will depend on what abilities and tools you have. Some people have good luck bending the receiver across a chunk of rod bolted down to a table. Other guys will spend quite a bit of time tweaking and fixing their receivers after taking this approach. (mallets, channel locks, vise grips, vises, etc) I made my own jig. I'm planning on taking some photos of it and posting a thread about it for everyone's benefit. I'd like to get that done in the near future, but I've been swamped at work and my truck just broke, so that comes first... |
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Wow thanks for the info. As far as what I have is the flat and the weld on sight pieces
As far as tooling and ability I am currently at school for Manufacturing engineering and I have a full machine/ weld shop available so i would much rather build a jig and bend it the right way Also I think This first build I am going to keep as a 93 and the next one go with the sbr 53 style So you should definitely create that thread or if you would mind IM me those pics of you jig, the main concern it the diameter of the rod to bed it around Thanks Alot |
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Quoted:
By "weld kit" do you mean the parts kit (torched/cut H&K firearm), or just the small receiver pieces that are needed during assembly? Rim Country Manufacturing makes HK 53 barrels and trunnions. (I've not done business with them myself, but have heard good things about them) I'm planning to build an HK93 sometime in the future. (No SBR's in NY, unfortunately) I'll be getting a HK93 parts kit, US receiver flat, US trunnion, US barrel and 3 US trigger parts (no muzzle device). Or maybe a US cocking handle and reuse the old trunnion, don't know yet. I believe the 6 parts is all I'll need for 922(r) but will double check that before building. Revised, you are right 6 since no muzzle device. Otherwise you need 7. I think the 93 has 17 parts on the list. I looked on military Firearm.com and this is what they listed: The parts on the list pertaining to the CETME or HK91 style of rifle are as follows: (1) Frames, receivers, receiver castings, forgings or stampings (2) Barrels (4) Mounting blocks (trunions) (5) Muzzle attachments (flash hiders or muzzle breaks) (6) Bolts (7) Bolt carriers (8) Operating rods (charging handle) (10) Trigger housings (FCG cage) (11) Triggers (12) Hammers (13) Sears (15) Buttstocks (16) Pistol grips (17) Forearms, handguards (18) Magazine bodies (19) Followers (20) Floorplates That makes 17 compliance parts. If you cannot have more that 10 IMPORTED parts in your rifle, then you must replace 7 of the above parts with US made replacements. (6 replacement parts if your barrel was cut and no muzzle attachment was added) So I take that as needing: Flash Hider Barrel Trunion Receiver Trigger Hammer Sear |
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Last I heard, SBR's were exempt from that 922(r) nonsense, .. nope Taylor, when did this change? I remember always hearing/reading/seeing "SBR's are exempt from 922(r)" for a long time. Then maybe a couple months ago I saw rumor here and there that it was not the case anymore. edit: I just did some googling, I get maybe 50/50 SBR's exempt or not. Also found this letter: http://www.nfaoa.org/phpBB2/viewtopic.php?t=161&sid=4dd6af74610e222ced3c6524f2f354eb I will try to do some more research when I have time, but I'd appreciate it if you have any leads you could give me. |
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I was going to post my own "check out my bending jig" thread, but I figured that we already have one "bending jig" thread running.
Probably best not to sorta dupe it, so I'll put this here. I hope you'll forgive my photography. I was using the camera in my phone and rushed the photo taking a bit. It was kind of an afterthought during the project. Basically, I got an LSC MP5/HK94 flat, measured it and compared it to the receiver piece I got with my parts kit. From my examination of the flat and receiver piece, the only difference in the sheet metal was the bend. Everything appeared dead on right up into the final bend. I measured & did some internet research (YMMV, of course) and the inside diameter of the "upper tube" portion of the H&K receiver is 20mm. My LSC flat measured .045" thick. 20mm ~0.787" 20mm + (2)0.045 = 0.877" 0.877" struck me as being suspiciously close to 0.875". I had an idea, drew some sketches and made a couple basic CAD drawings. 
In short, I bought a 7/8" ball endmill and cut a trench through a 2x2 piece of crs. of course, I roughed it w/my carbide endmills and did a couple passes offset slightly to get 0.877" or 0.878". Yeah, the bottom is a flat ~0.001-0.002 across, but I figure it didn't matter much. Then I went back with a 1/4" and 1/2" endmill to cut clearance "slots" in the bottom and sides for receiver ribs and claw mount tabs. I made the punch/form tool from a piece of 20mm ground stock and a 1"x2" piece of crs. Dowel pins on the ends to align everything. I run two bolts to pull the jig closed, second hole from each end. (nut on top, bolt head in a slot on the bottom, so I can wrench on just the nut) I put two shcs's in the top of the die to use as a position stop. Here's my jig: 
I know it's not as advanced as some of the jigs out there, and it may be somewhat overkill/wasteful of material but, I tend to be a fan of the brute force approach on this type of project. I didn't really need to think to design it and I could make it w/what I had available. Of course, it took a while running the 7/8" HS ball endmill at 2IPM down the length of the bar... I only had the hk94 project at the time, but I did make it long enough to run a g3 flat, I just need to go in and add the rib & claw mount clearance slots. 
Two problems with this jig: 1) There is no allowance for springback or anything like that. IIRC, I got the thing closed down on the receiver, but the two sides did not touch. I went in with a c-clamp to bring them together (perfect alignment btw) for welding (while on the jig). The inside of the rails on either side of the receiver touched flat against the form during this (I measured the receiver bits and sized the square piece in there to work like that). Once removed from the jig, my receiver was ~20-40 thousandths too wide. I fixed this by putting it in the vise, squeezing it, then measuring, repeated several times until I was happy with it. 2) More specific to my particular jig. I did not ream the two dowel pin holes on the form large enough. They bind and I need to crank the thing in the up and down directions. If I open these up I could put springs in there for an auto-opening effect. (or leave it, theoretically it's more accurate this way, right?) -boonie |
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Last I heard, SBR's were exempt from that 922(r) nonsense, .. nope Back in 2007 or so NOBODY said 922r applied to SBRs. Then a few monthes back the NFA lawyer in SAR "clarified" it by saying 922r only applied to rifles built on imported receivers. Now it appears to be back to 922r NOT being relevant. Let's see what the ATFE says next month. |
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I will try to do some more research when I have time, but I'd appreciate it if you have any leads you could give me. somebody wrote a letter and you know the rest. 
The letter is on NFA bardwells site Quoted:
Back in 2007 or so NOBODY said 922r applied to SBRs. Then a few monthes back the NFA lawyer in SAR "clarified" it by saying 922r only applied to rifles built on imported receivers. Now it appears to be back to 922r NOT being relevant. Let's see what the ATFE says next month. This is the other problem, they have said both, so which is the "law" Non one knows with the fuckin ATF |
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jakjak, I was worried about the rod deflecting during the bend, I wanted to stiffen it, hence the rib.
(it is pretty long, I believe I have ~1" clearance on either side for a G3 length receiver) It also made it easier to put the dowel pins and bolts on there. I figure that by the time I put flats and the thru holes for the bolts/pins on a 20mm rod, there wouldn't be a lot of material left. Those are 1/2" bolts (12.7mm). 20mm - 12.7mm = 7.3mm 7.3mm/2 = 3.65mm = 0.14" That's 0.14" on each side at the thickest part of the 20mm rod and of course, you need a little bigger than 1/2" for the bolt holes. Like I said, the thing needed some tweaking after it came out of the jig. I encourage you to look at other jigs and put some thought into this. You might find an easier jig to build that works better. (Or not, I dunno, I'd just hate to see you copy this and have trouble w/it.) Taylor, I checked my bookmarks and did some googling, has Bardwell's site moved? I can't seem to find it. I've found a few mirrors, but they appear to have been last updated back in 2002 or so. |
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Taylor, I checked my bookmarks and did some googling, has Bardwell's site moved? I can't seem to find it. I've found a few mirrors, but they appear to have been last updated back in 2002 or so. http://www.titleii.com/bardwell/atf_letter3.txt also look in the legal section, there is another letter that has been posted on this site that says the opposite
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jakjak,
I haven't seen any sites with good instructions on welding the flat. I would suggest looking at the parts you get with your parts kit, before cutting the trunnion out. (Maybe take pictures of the welds). That and just look at h&k photos online, you can usually see the welds in them. edit: Found this, haven't followed the links all the through. (Also don't have a military firearms account) http://hkpro.com/forum/showthread.php?t=119108 |
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