negev5021 25 Posted August 11, 2010 Report Share Posted August 11, 2010 (edited) After getting my S12 up and running, which took some time, my confidence level in tinkering had grown significantly - removing gas block, enlarging ports, increase barral hood size, feed ramp mods ect made me feel like I could do just about any mod I wanted. The one that felt too complicated was the left side charging handle, which, after much thought, I just went for. I had some help from my buddy with the right tools, and here is how it went: First, I bought a Tapco piston rod from CSS for like 11 bucks: Uploaded with ImageShack.us I cut the threaded side off with the dremel: Uploaded with ImageShack.us After setting it against the carrier, it looked like it was too big around, and welding would get in the way of the action: Uploaded with ImageShack.us so I wanted to make it smaller. At this point I was intent on doing the whole thing in my basement (ie minimal tools), other than some quick welding, so I put the cut rod in the cordless drill and took it to the grinder: Uploaded with ImageShack.us I tested it on the long side I would clearly not be using, and had the drill turning the opposite direction of the grinder, and turned it down pretty quickly to this: Uploaded with ImageShack.us I realized that it would be short from the piston head to the carrier, and the taper would increase the size and deafeat the purpose of turning down in the first place, and the grinder would not get detail enough to remove it, so I busted out the dremel again to remove the transition: Uploaded with ImageShack.us I ended the night with what I figured would be the finished handle: Uploaded with ImageShack.us The next day I wanted to take the new handle with the gun to my buddy, just to see how much room he needed to weld, should I chamfer(?) and basically get the piece ready for him to weld. He was pretty stoked on the idea and dove right into helping me bust it out right then and there. His primary concern was having a strong enough weld to hold it on, and it was determined that drilling a hole in the carrier would provide extra strength and relieve some of the recoil forces from the weld, so he measured my work from last night and took a carbide bit on the drill press and drilled a 1/4 inch hole into the carrier: Uploaded with ImageShack.us Uploaded with ImageShack.us A quick cut and the handle fit right in: Uploaded with ImageShack.us Then it was determined that a silver braze would be better suited than weld, which we did next: Uploaded with ImageShack.us Then cooled it off at the water fountain: Uploaded with ImageShack.us It fit pretty well right away, I have some filing to do, but relatively clean install: Uploaded with ImageShack.us Then it was time for the top cover, which I intended to do with a dremel/file, since it was tough thinking how to support in the mill. My buddy kept it simple, and put a long socket inside and clamped from there - you can see it in this pic: Uploaded with ImageShack.us a couple of passes and it was set! We eyeballed the length and it came out sweet: Uploaded with ImageShack.us Overall time was about 2 hours, difficulty level I would say 6 out of 10. Drill/Mill was absolutely priceless in making it easy, cobalt bit to drill the carrier was crucial. Overall cost was $11 and a 12 pack. Can't wait to get this out for a test run! Edited August 11, 2010 by negev5021 7 Quote Link to post Share on other sites
chupa 34 Posted August 11, 2010 Report Share Posted August 11, 2010 nice write up, negev. Quote Link to post Share on other sites
308SAIGA 55 Posted August 11, 2010 Report Share Posted August 11, 2010 Very nice, this is what I wanted to do with my 308, this deserves a sticky..... Please let us know how she functioned.... Quote Link to post Share on other sites
Paladin 37 Posted August 12, 2010 Report Share Posted August 12, 2010 Bravo, nicely done. You know, I do happen to have a Bridgeport mill in my shop....mmmm Quote Link to post Share on other sites
SirROFL 13 Posted August 12, 2010 Report Share Posted August 12, 2010 I'd like to hear how the silver is holding up to the recoil as opposed to a weld, though I'm sure the slot drilled into the carrier will help. 1 Quote Link to post Share on other sites
Nailbomb 10,221 Posted August 12, 2010 Report Share Posted August 12, 2010 this deserves a sticky..... I agree. This Is EXACLY the kind of thing I love seeing on here. Quote Link to post Share on other sites
Nailbomb 10,221 Posted August 12, 2010 Report Share Posted August 12, 2010 Do you mind uploading the pics to the forum instead of using imageshack? Quote Link to post Share on other sites
Klassy Kalashnikov 1,393 Posted August 12, 2010 Report Share Posted August 12, 2010 Awesome tutorial, thanks for posting this. I love the minimalist method tutorials like this, it's the best part of the AK platform IMO. Quote Link to post Share on other sites
negev5021 25 Posted August 13, 2010 Author Report Share Posted August 13, 2010 (edited) Do you mind uploading the pics to the forum instead of using imageshack? Not quite sure how to do that, but I will try here. After getting home and playing around with the conversion I noticed that the top cover was not milled out enough. The action would cycle, and I could get to BHO, but when releasing the BHO it moved further back than the cover would allow, and I could see the cover moving. So I had to open it up all little more with the bench grinder. What I would suggest is after you get the handle on, pull the bolt all the way back, till it hits the rear trunion, and mark it: Then when you put the top cover back on you can see how far you have to go: I will try to upload photos direct on the first post Nailbomb, I think I got it now. Edited August 14, 2010 by negev5021 Quote Link to post Share on other sites
MT Predator 2,294 Posted August 14, 2010 Report Share Posted August 14, 2010 Nice, let us know how the silver solder holds up. Quote Link to post Share on other sites
Nailbomb 10,221 Posted August 14, 2010 Report Share Posted August 14, 2010 Nice, let us know how the silver solder holds up. In this application I wouldn't be worried. What is the tensile strength of a brazed joint? Joint strength depends on several factors: clearance between parts, base metal composition, service temperature and joint quality (low voids, good penetration). Joint design will also affect strength. The bulk tensile strength of silver braze alloys is 40,000-70,000 psi. When brazing copper-based alloys, failure will occur in the copper or brass. For copper this is usually the annealed strength of the copper alloy. When brazing steel or other ferrous metals, joint strength over 70,000 psi can be achieved under the right conditions. Keep in mind that braze joints are primarily lap type joints, so strength is a combination of tensile and shear. Joint strength is directly influenced by the above mentioned factors. The only way to accurately determine tensile or other values is to test the brazed assembly. being that side stress is the major factor in this case, and he counter sunk the welded joint(ie: drilled) I wouldn't be worried in the least. If properly braised it will last longer than his grandkids. Quote Link to post Share on other sites
negev5021 25 Posted August 16, 2010 Author Report Share Posted August 16, 2010 Range Report: Silver braze lasted approx. 50 rounds, and flew off and smacked me in the face! Bummer, but better now than match day this weekend. Back to the drawing board... any idea on the best weld/attachment method? Quote Link to post Share on other sites
308SAIGA 55 Posted August 16, 2010 Report Share Posted August 16, 2010 Could this have been done with a TIG welder? Or would this not hold up? TIA 1 Quote Link to post Share on other sites
Nailbomb 10,221 Posted August 17, 2010 Report Share Posted August 17, 2010 TIG would be stronger than silver solder. Just out of curosity, did you use use flux when you braised? Stainless to mild steel is a bi-metal joint and you probably need the flux to help it flow. Quote Link to post Share on other sites
L5K 162 Posted August 18, 2010 Report Share Posted August 18, 2010 Range Report: Silver braze lasted approx. 50 rounds, and flew off and smacked me in the face! Bummer, but better now than match day this weekend. Back to the drawing board... any idea on the best weld/attachment method? Tap the hole, thread the new handle, screw it in, then weld it. Best solution I can think of at the moment. 1 Quote Link to post Share on other sites
negev5021 25 Posted August 18, 2010 Author Report Share Posted August 18, 2010 Not sure about the threading thing, as the hole is drilled, and larger than the part that goes in there. Perhaps a new handle? I took it back to the dude who did the brazing, and he had his dad do it this time. I was sceptical about doing the same thing twice, but being totally unknowledgable of the issue, I bit my tongue and let the guy go. He appeared to do it differently in that he brazed a bit, then took a wrench and turned the handle to apparently work the braze into the hole. Here is a pic of the broken unit: You can kinda see that the braze was just on top of the seam, leaving a ring around it, but not down the hole. I sure hope it works! I was also hoping he would TIG weld the thing really bomber, but in hindsight, there is little room for a seam around the handle without hitting the reciever on the bottom, the top cover on the top (easy enough fix), or the trunion in the front that would prohibit lock up, so if they think this will hold up, we shall see. Tough part is I won't be testing prior to 3 gun this weekend, so flyin blind! Quote Link to post Share on other sites
L5K 162 Posted August 18, 2010 Report Share Posted August 18, 2010 Yea if you did thread it you would have to make a new handle, but I would trust it more than brazing or welding alone. Quote Link to post Share on other sites
Oldfalguy 0 Posted August 23, 2010 Report Share Posted August 23, 2010 All I can say is this is a great idea to do- While threading would help I am not sure its possible on a hardened bolt. Mig or TIG would work but I bet the hole would have to be bigger to fill with metal and stay out of the way of the cover and receiver. Quote Link to post Share on other sites
Heath_h49008 442 Posted August 24, 2010 Report Share Posted August 24, 2010 (edited) I actually used a piston for my left side handle. I just cut it to length and tig'd it on in the same spot you drilled and torch welded. Mine works fine. I think you turned it too thin, and the heat from the torch weakened it further. Edit: Sorry, I reread the whole thread and realized the shaft didn't snap. If you TIG the handle on with a good weld, you can grind off any excess to clear the trunnion and the receiver without compromising anything. You may not even need to bevel/fill the handle at the joint, although that makes for a larger contact if you're worried. Again, mine works fine. Edited August 24, 2010 by Heath_h49008 Quote Link to post Share on other sites
negev5021 25 Posted August 24, 2010 Author Report Share Posted August 24, 2010 Well, shot the match last weekend and everything held up, so I am feeling better about the 2nd braze. Time will tell - I did have a few FTF again which is getting pretty old... but clearing them was much easier with the charging handle on the left. One day this thing is gonna work 100% - Quote Link to post Share on other sites
que45 2 Posted February 28, 2011 Report Share Posted February 28, 2011 If you mill the bolt down about an 1/8" around the hole you drilled and Tig weld it. Its not coming of without a fight Quote Link to post Share on other sites
poolingmyignorance 2,191 Posted May 29, 2011 Report Share Posted May 29, 2011 There is ONE THING I saw nobody mentioned here. I suspect what cause this failure was the rapid cooling of the braze under water, cause the steel to become brittle. I have done my own charging handle and used tig to weld them. The procedure I used is as follows: Charging handle material: 304ss Tig rod : 1/8 309ss No preheating required unless ambient tempature is under 60 f (though this is debateble as some say the carrier on the s12 is chrome/molly which should be preheated, and heat treated after welding) I personaly don't prefer to heat treat machined parts unless absoultely nessesary as they tend to warp. I DO recomend slow cooling your welded product by means of wrapping in insulation and letting cool to ambient tempature. I did not do a Left side handle I did a right upswept but reguardless of that you would be better to countersing a slight indentaion and bevel your handle piece to get a better penetrating weld. 1 Quote Link to post Share on other sites
2ndAmendican 23 Posted July 25, 2011 Report Share Posted July 25, 2011 Drilling and tapping the carrier, and threading your piston rod shank is probably the best method, but I wouldn't even weld it. You can roll pin it so it's removeable. Similar to the rivet holding an AK piston assy into the carrier. Look at the pic in post #9. You can drill straight down through the carrier, and install a roll pin to prevent the handle from the threads backing out. That way if you ever do want to change it, you can fairly easily. Just my 2 cents. Quote Link to post Share on other sites
poolingmyignorance 2,191 Posted July 25, 2011 Report Share Posted July 25, 2011 (edited) Drilling and tapping the carrier, and threading your piston rod shank is probably the best method, but I wouldn't even weld it. You can roll pin it so it's removeable. Similar to the rivet holding an AK piston assy into the carrier. Look at the pic in post #9. You can drill straight down through the carrier, and install a roll pin to prevent the handle from the threads backing out. That way if you ever do want to change it, you can fairly easily. Just my 2 cents. I see two problems with drilling and taping like this: 1) Just like the op rod..over time it will wear and begin to wobble, and removing a tapped bolt that's been "set" isn't easy. It tends to eat up threads and gald, especally on stainless type alloys. 2) If you wish to change it or go back, now you have a hole to fill with, with what exactly? If you had a weld on handle you just chop it off with a saw, whip out the grinder, flapper wheel or file and feather it in....it'll look like it was never even there. Most importanly about welding is it's permanet and STRONG with ZERO possiblty for wobble or wear, if done correctly. Not trying to argue, but you might want to ask yourself "why don't the pros ever do this?" If it's so much better. Just my opinon. Edited July 25, 2011 by poolingmyignorance Quote Link to post Share on other sites
Viper 1 0 Posted September 23, 2011 Report Share Posted September 23, 2011 Nice outside the box thinking on this mod, I feel that the piston was fitting as it is the symbol of the Saiga/AK's reliability. Quote Link to post Share on other sites
BCOWANWHEELS 0 Posted May 7, 2012 Report Share Posted May 7, 2012 TO WELD STAINLESS CORRECTLY YOU REALLY NEED TO HAVE A OXYGEN FREE WELD AREA. THATS WHY THEY PURGE STAINLESS PIPES WITH CO2 INSIDE BEFORE WELDING.... Quote Link to post Share on other sites
poolingmyignorance 2,191 Posted May 8, 2012 Report Share Posted May 8, 2012 Yes on a butt weld (stringer) for a pipe you need to purge, but not for a structural weld, the gas shield from the nozzle is sufficient in most cases.Especially if you cheat like I do and use an oxygen regulator, and really crank up the flow. You can have a fan blowing right on ya while ya weld and you wont' have to worry about porocity. And typically you use the same gas that your welding with, which never in my experience has been Co2. Quote Link to post Share on other sites
NSA_CJ 2 Posted July 3, 2013 Report Share Posted July 3, 2013 Nicely laid out sir. I love the idea of an ambidextrous charging handle design. Keep up the good work Quote Link to post Share on other sites
MonaDeRio 2 Posted April 18, 2019 Report Share Posted April 18, 2019 (edited) I vote for drilling and threading. So here is my way: 1.1" or 1.25" or 1.5" steel shoulder bolt (screw) 5/16"-18, shoulder 3/8". get any size you like. 2. Drill bit 17/64" Cobalt 3. 5/16"-18 tap set of 3 ( tapper, plug, bottom) 4. Red thread locker or any high strength epoxy. 5. My experience in metalworking. 6. I have the multi process welding machine but I prefer a simple way. Edited April 18, 2019 by MonaDeRio Quote Link to post Share on other sites
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