stripped front lug

[Benaiah]

 I need some advice about my rifle. I don't know how I did it, but I managed to strip out the threads on the front recoil? lug on my sporterized Persian mauser. What can I do? I thought of getting a smaller 1/4 x 20 socket head screw from Lowe's, covering it with release agent, then filling the stripped area with JBweld. Maybe that would kinda make new threads, once I removed the screw from the hole. Just a crazy idea, but I have to come up with something. Any advice would be welcome.

Thanks

[trotterlg]

Put a helicoil in it and it will be fixed right.  Larry

[gunnut69]

I've never used a helicoil in this type situation but I've not seen a mauser front screw stripped! If the helicoil doesn't work out I'd consider the next size bigger screw and a bit of customizing.. Are you certain the action screws stripped? New screws are fairly easy to come by..

[slimjlm]

The Helicoil would be my choice, they bear the load over a larger area than the original threads and would probably be stronger than it was.  Casting new threads with JB will be weak and wont last long, they used to sell a Loctite kit to do that and it was okay for low strength holding, but only where you couldn't get a Helicoil into it.  I do like opening everything up to the next size, more of an upgrade than repair!

[Benaiah]

Well, now I have an update. I was trying to put a new screw into the lug and it broke off. Tried everything to get it out, and it brofe off in the lug. As best as I can describe it, the front lug on my rifle is a rectangular piece of metal on the bottom of the reciever, and on that piece of metal was another round threaded piece into which the front screw attached. The screw itself and the lug were stripped. Anyway, so now here I am with the screw broken off in the lug. Couldn't get it out, so I end up grinding the round threaded piece down flush, so that what is left is the rectangular section that I spoke of earlier. There is plenty of steel there to use, so what I am thinking is that I can drill and plug tap this section, get a new screw, and all will be well. What think ye?

[gunnut69]

I'm hearing you say you ground off the bolt hole on the recoil lug of a mauser rifle. It sounds to me as if you stripped the threads from the bolt and left them in the hole. Then you tried to install another screw into a hole with the threads full of metal that was stripped from the front action bolt.?? I suppose with proper precautions one could weld a small piece to the recoil lug/front action flat and drill/tap a hole for the front action screw. There will have to be somoe inletting done and heat management around that front receiver ring is paramount!!!! Soften the case hardened lug abutments and you will end up with junk. Perhaps it's time to find a good gunsmith and let him correct the problem.. 

[Benaiah]

So basically what you are saying is, I screwed up. No pun intended. It's cool, I have a good friend that does amazing work with old mausers. At the very least, I could get another 98 action and put my barrel on it. Thanks for the advice.

[gunnut69]

In a word, yes. It's almost always best to have a plan to replace a part on any rifle before grinding it off.. Especially the area of the action that holds the rifle together. Good luck..

[Benaiah]

Ok, Gunnut. New update. First, thanks for the great advice. I'm not completely inept as far as gun repairs go, just got impatient with this project, and angry with myself for screwing it up after all the work I put into this thing (bedded the action, added a grind-to-fit recoil pad and refinished the stock). I did have a plan in mind when I ground the lug protrusion? off, which is what I did today. I assembled the rifle, minus front screw of course, center punched the abutment where I had ground it, disassembled the rifle, drilled and tapped it for 1/4 x 20 machine screw, added some Loctite to the screw and reassembled. I was very careful to not drill into the chamber, only as deep as needed to get some threads tapped. Seems to be fine, so far. Everything is tight. Now my question is this, is that steel that I drilled and tapped strong enough to hold that together?

I hope this photo shows. It is what I am trying to describe. You'll notice on the left side of the picture, about where the first knuckle is on the hand, is the bolt hole protrusion is located that I am talking about. That is what I ground off, not the entire abutment. I hope that helps.

http://i801.photobucket.com/albums/yy295/intolerantMarine/mauseraction.jpg

[gunnut69]

There appears to be a protrusion still there? Or is that the head of the 1/2 x 20 bolt you installed? The front receiver bolt is the most important of the 2 on the mauser but if it holds the action down and the bottom metal on it should be OK. Have you shot the rifle yet? If bedded correctly there is no more strain on the front screw than is applied by the screw driver installing it..

[Benaiah]

Sorry, I should have clarified the picture. The picture is not of my rifle. I searched the web for picture of a mauser, so that I could show you what I was talking about. I should have taken a pic of my rifle, after I did the drilling and tapping. Anyway, that protrusion that you see in the pic is what I am taking about. It no longer exists on my rifle, being ground flat. As far as the bedding is concerned, it is good and tight, and done exactly as directed in the instructions ( my first job). I have not fired it yet. Waiting to install a new scope, and take it to the range. Once again, thanks for the advice. BTW, what is a helicoil?

[slimjlm]

Heli-coil sets are sold at auto parts stores, many hardware stores, and online in staggering variety of thread sizes and normally come with three basic components.  You get a special oversized tap, heli-coil, and a installation tool.  The tap is the same pitch as the threads you are replacing, but is larger enough to make room for the heli-coil.  The heli-coils are stainless spring steel wire in a diamond profile wrapped to match your thread pitch and slightly larger in diameter.  The installation tool allows you to turn the heli-coil into the hole from the bottom, contracting the heli-coil like when you twist a spring in or out of a tight hole, one way makes it tighter, while the other sets it free.

You start by drilling the hole to a standard size (as specified on the tap, if not already stripped to that point), then run the tap into the hole nice and straight, next you install the heli-coil with the tab in (after cleaning the hole, of course), then break off and remove the tab.  

Most of the time it's that easy and then you have the proper size threads again and no one is the wiser! They rarely need anything other than the friction between the heli-coil and the material to keep them from backing out, but can be Loctited in place if needed. And since they bear on a larger area than the initial threads and are made of high strength steel, they are often stronger, especially in low strength materials.  They are what I use and recommend in ANY stripped thread application you can get them into.  

A Kit:


A Heli-coil:


And an installed cut-away:

[bilmac]

Maybe your action is different but I seem to remember that the front action screw of a mauser is very close to 1/4 x 20. I have put headless 1/4 x 20 bolts in the hole for try bolts when I inletted. So maybe somehow did something smaller get picked up and used instead of the right screw and that is why it stripped in the first place? It seems to me that if you have it tapped out to 1/4 inch now it may not have cleaned up enough of the old hole and threads to be really sound, or maybe it did. I think I would just use it and watch it and maybe someday you may have to try to tap it out to something a little bigger.