Receiver welding jig

Teach · November 2015

A few days ago I mentioned a project where I plan to shorten a small ring Mauser receiver for use with cartridges "picked green"- - - -ones with case lengths and/or case head diameters smaller than standard cartridges like the .308, .30-06, etc. Here's the beginning of the project- - - -shortening the receiver. Then the bolt, magazine, follower, etc. can be fitted to the reduced-length receiver. This one will also be getting a modified large-ring bolt in place of the cock-on-closing item standard for a small ring action. Fortunately, Mauser parts can be interchanged with just a little bit of tweaking.

I'm waiting on a piece of copper round stock that I ordered on Ebay to be machined into a heat sink to protect the heat treatment of the front receiver ring during the welding process.

After the parts are tack welded together in the proper alignment and the bolt stroke is checked to be sure there's no binding, then the welds will be completed and finish-machined. Of course, a non-standard stock inletting procedure will also be necessary, as there's no such thing as a semi-inletted stock in the action length I'll have when the project is completed! Fun and games!
Jerry

rberglof · November 2015

Thank you for the pictures of this project Teach, very interested in seeing it to completion.

early · November 2015

You have an amazing amount of knowledge and experience.
Does the ring contain all the pressure excepting the bolt breech face?

Teach · November 2015

The locking lugs of the bolt and the mating flange in the receiver ring carry the thrust of the cartridge firing, so everything behind the receiver ring is simply to align the bolt and guide the cartridge into the chamber. As long as the heat treatment of the bolt lugs and the receiver ring does not get compromised, welding, machining and/or reshaping of parts doesn't affect the safety of the action. Now, the 03 Springfield is a Mauser-type action with the same type of lockup, but the entire receiver is harder than woodpecker lips! Any rework of an 03 requires that the heat treat be redone, which is one reason why some of the folks at CMP are such donkeyholes to anyone who mentions any type of sporterizing of an 03 action. I have an idea most of them are just a bunch of jerks to begin with, however!
Jerry

early · November 2015

Great!
This will be cool to see it progress.

sarg1c · November 2015

Teach wrote: »

The locking lugs of the bolt and the mating flange in the receiver ring carry the thrust of the cartridge firing, so everything behind the receiver ring is simply to align the bolt and guide the cartridge into the chamber. As long as the heat treatment of the bolt lugs and the receiver ring does not get compromised, welding, machining and/or reshaping of parts doesn't affect the safety of the action. Now, the 03 Springfield is a Mauser-type action with the same type of lockup, but the entire receiver is harder than woodpecker lips! Any rework of an 03 requires that the heat treat be redone, which is one reason why some of the folks at CMP are such donkeyholes to anyone who mentions any type of sporterizing of an 03 action. I have an idea most of them are just a bunch of jerks to begin with, however!
Jerry

stress relief would be necessary after welding....

Big Al1 · November 2015

This project should keep you out of Miss Mary's hair for most of the winter!! Looking forward to the finished product!!

Teach · November 2015

sarg1c wrote: »

stress relief would be necessary after welding....

Shot-peening or beadblasting should manage that pretty easily.
Jerry

Freezer · November 2015

Cool project!

Squeaky....Squeaky

tubabucknut · November 2015

That is cool teach. Is there some sort of tempering that needs to be done after? Are actions hardened when made?

Teach · November 2015

Only the front of the Mauser action is heat treated. The locking lugs on the front of the bolt and the corresponding lugs inside the receiver ring are hardened and tempered to avoid wear or lug setback from recoil. Anytime any welding is done elsewhere on the action, or the bolt handle is heated and bent, etc., a heat-conducting device is used to prevent overheating of the heat-treated areas. The "heat sink" can be copper (best) aluminum, or even steel, and "heat-stop paste" can also be applied to slow down the heat transfer during the forging/welding process. Back before the environmental wackos got involved, water-soaked asbestos was used to isolate heat-sensitive areas from damage.
Jerry

tennmike · November 2015

That's a nice shop made jig for holding the action pieces in alignment for welding. :up:

Regarding the unavailability of asbestos, wet fiberglass can be substituted for the asbestos. And the white really dense fiberglass is really similar to the asbestos regarding texture and moisture retention. A friend from work that TIG welds a lot has a huge supply of it 'liberated' from the scrap bins at work.

Teach · November 2015

Sounds like a plan! Isn't there a tendency for the glass fibers to melt and bond to the workpiece?
Jerry

JasonMPD · November 2015

Teach wrote: »

Sounds like a plan! Isn't there a tendency for the glass fibers to melt and bond to the workpiece?
Jerry

"Generic" fiberglass has a melting point of about 1300°F. I think you'll be ok. If you get the steel that hot you'd be disrupting the temper anyways.

Maximum working temp is generally about 1000-F.

Teach · November 2015

An acetyline torch flame is 6,000 degrees- - - -a TIG arc is noticeably hotter. The whole idea behind a heat sink or heat stop compounds is to prevent the heat from migrating to a place where the heat treatment is important. There's no way to weld without getting above the critical temperature of the steel. Stress-relieving a weld by post-heating and slow cooling, like in a bed of sand or lime is important, also.
Jerry

JasonMPD · November 2015

Teach wrote: »

An acetyline torch flame is 6,000 degrees- - - -a TIG arc is noticeably hotter. The whole idea behind a heat sink or heat stop compounds is to prevent the heat from migrating to a place where the heat treatment is important. There's no way to weld without getting above the critical temperature of the steel. Stress-relieving a weld by post-heating and slow cooling, like in a bed of sand or lime is important, also.
Jerry

I got that.

But will that welding process produce 1200+F 3 inches away from the weld point with the soaked fiberglass and copper heat sink in place? I bet not.

snake284 · November 2015

Back in the 80s or 90s whenever, a bunch of guys in our gun club that worked at Alcoa across the bay here were building re-weld Garands. Seems the Gubermint at some point decided to cut up some Garands instead of sell them through the DCM. Then some enterprizing souls gained access to what was left and built jigs and did what you're doing, rewelded the actions and built their own Garands. They were passing that jig around to each other welding their new (To Them) Garand receivers up. There were a couple that had to be redone but most turned out fine and shot fine>

early · November 2015

I think the Garand receivers are subjected to a different type of stress during cycling.

Teach · November 2015

cpj wrote: »

Problem solved.

http://www.jegs.com/i/JEGS-Performance-Products/555/32069/10002/-1?parentProductId=1225481

Not at that price! I'll put a $10.00 pair of mechanic's Kevlar gloves in a blender if I want some super high-temp fibers!
Jerry

tennmike · November 2015

Jerry, regarding the fiberglass, if you keep it soaking wet, it won't melt or stick to the part being welded. The guy I know that uses it has shown me some he used after TIG welding parts about the same cross section as your receiver. The soaking wet fiberglass will ball up any spatter like solder on a wet sponge. And as long as you keep it wet, it won't stick. TIG welding is hot, but localized to the weld site with heat transmitted through conduction away from the weld.

Another welding trick he uses to keep heat from traveling is to use copper buss bar material clamped on either side of the area being welded. The copper wicks away heat fast.

Teach · November 2015

I've got a 1 1/8" diameter X 9" long piece of solid copper round stock on order. One end is going to get a small ring Mauser barrel thread, and the other will get a large ring thread. It will be long enough to butt against the bolt locking lugs in the receiver ring. That should wick enough heat away from the lugs to prevent any compromise of the heat treat, especially if I submerge the other end in a container of ice.
Jerry

DoctorWho · November 2015

I have ( what is likely a dumb ) idea, what if the round stock is hollow and you pump some sort of chilled liquid coolant through it ?

Guns and Ammo

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