I'm assembling the piece-parts for a Krag buildup in a chambering like 405, 40-70 SS, 35 WCF or 444M, exact caliber choice is immaterial at this point.

I'm considering modifying the action for engagement of both lugs instead of only the front one. Following the theory of FUBARing (grin) the cheapest part first, I've decided to try to add metal to the bolt on the rear of the rear lug surface. Have not measured the existing clearance but urban legend suggests that it's about 0.005" or perhaps a bit less.

Like Paul Simon says, there are fifty ways. But which one would be best in this circumstance?

My inclination is to try to find a shop that specializes in adding metal in such small-but-critical dimensional changes, but I don't particularly trust any plating to remain in place 100%.

Points to ponder:
Steel is low-carbon with no exotic alloys
Action will be lapped-in during buildup

The ideal solution would be to find a shop that specializes in doing this work on Krags. Hah.

Any other shop/source solutions?
TIA, Joe

I would not accept plating.
Do you mean low carbon or carburized low carbon steel ? Do you intend to reheat treat ?
Step #1 of this process would mean checking for cracks with dye penetrant /magnetic particle tests of the forward lug.

Bolt body is NOS circa 1900, Springfield Armory steel of that time and, as I say, is never-before-used New Old Stock. It was originally carburized/case-hardened in some fashion at Springfield.

I'm familiar with all sorts of NDE and the bolt will be checked both before and after any mods.

I could always get it TIGed locally and then re-heat-treated as necessary but I was hoping to find a shop that specializes in this sort of thing with possibly (ideally) no re-heat-treat required. I've heard of some sort of micro-spray (?) welding for doing such small work but have no specific knowledge of any local shops that use it.
Regards, Joe

JD,
It would be far better and easier (means less opportunity to screw up) if you remove the metal from the back side of the front lug, especially if you only need .005. You can grind off .001 at a time until the back lug touches. Do that instead of welding on the back one where the possibility of warping the bolt is pretty easy unless you have someone who is good at micro-welding.

Joe,

It seems, in my distant, cloudy past, I remember something about metal spraying as used to build up crankshafts and camshafts for re-grinding. I wonder if this may be applied to your need for the Krag? No pun intended. Perhaps a call to a local hot rod machine shop would produce answers or, at least, another avenue of pursuit.

Luck,

Stephen

de Haas (Bolt Action Rifles) refers to Griffin and Howe lapping the front lug until the rear touches. I'm not sure how thin this would leave the case. You may need to recarburize.

I don't know about on rifle lugs but I have been driving a 71 landcruiser that had the crank re built.That stuff is tuff.

Since Krags and ealry '03s ae notorious for extra deep carburizing I doubt removing 0.005" from the front lug will materially affect it's hardness or strength. Having the long and massive guide rib bearing on the action should more than compensate. My vote is lap or grind the front lug to allow the rib to engage. It's something that has already been done by others successfully.

This the famous rifle that cracked your ribs? Ken Hurst wants to hear the gory details.

Jerry Liles

Or use low-temperature silver solder to solder a piece of high-carbon steel shim stock in place.

By the way Joe, how are your shins? Saw them on another website and I thought you might have to amputate your legs!

quote:

Originally posted by clowdis:
By the way Joe, how are your shins? Saw them on another website and I thought you might have to amputate your legs!

I'm able to walk, a little, after over a week now. Without taking up a lot of personal bandwidth I'll just say that although the shins look pretty spectacular, their pain-&-suffering level absolutely pales in comparison to some other older rib-&-shoulder wounds that were re-wounded during The Baby-Gate Smackdown.

IOW I'm one hurtin' puppy right now.

The Krag stock breakage revealed musket grain in the wrist area plus it was never a silk purse anyway. I may take some photos of the repair sequence after I recover a little further...
Regards, Joe