quote:

Originally posted by dpcd:
Really? A file will not cut case hardened steel?
Come over and we can file on any number of at least 100 Mauser receivers of all makes and years. And I have many that you can't cut. Nickel steel 1917s, most of them, you can't cut. Some you can.

Not unless is was poorly quenched, or annealed after the quenching. You cannot file as-quenched case hardened mild steel. You can stone it, or use a diamond abrasive. This is what the English trade referred to as "hard fitting", which was necessary to correct warpage if it occurred.

The fact that you can file on a Mauser receiver in the hardened areas demonstrates that either the case hardening process failed, or that it was annealed (this is a "process anneal" not a full anneal which would leave the receiver dead soft) after it was hardened. This is indeed done most of the time.

I do case hardening myself and I always use a file to test for success. If the process was followed correctly, you CANNOT FILE CUT THE PART when it comes out of quench. And then I anneal at 425 to prevent the case cracking or flaking off. The latter is what explains why some vintage guns have a condition that looks like flaking chrome plating on the receiver: it's not chrome or nickel, it's the case flaking off.

I don't mess with through hardening as you have to control the process rather carefully, following a prescribed time/temperature curve, and in most cases you need an inert atmosphere. Other than springs and screws, that is, I make a lot of those, using the appropriate through-hardening alloys.

So when you say you can cut "case hardened steel", it's really annealed case hardened steel.

And at the risk of losing sight of the forest for the trees, I think the reason the actions were selectively hardened was not to prevent deformation under pressure, rather it was to prevent surface wear from opening and closing the bolt thousands of times with a good slurry of oil and dust as a de facto abrasive.

It has been shown that case, unless rather deep, does not prevent deformation, rather it's chosen precisely because it allows the part to deform without fracturing.

This will give those who like to lap the bolt lugs some indigestion. Go ahead and lap, but you may want to redo the case when you are done...

I see I am not communicating well to this group; so I conducted a little test this morning. Took a fairly new Nicholson Flat Bastard File. Also grabbed an assortment of 98 Mauser receivers and filed a notch on the bottom of the receiver ring on ALL of them, ALL of them. Not sure how to be more clear. No they were not all in a fire! All this proves that files are very hard and these Mauser receivers are not as hard as the file on the bottom of the ring. Proves nothing else.
Gew 98 Oberndorf 1917
VZ24 (2) Not surprised; these are very tough but not glass hard.
DWM Arg 1909 (2) Not surprised.
FB Radom WZ29 (one of the best quality makers)
Mexican 36
Kar98k dou45 and these are usually glass hard.
FN Commercial post war
Winchester 1917 (I was surprised on this one)

We'll give you the last word dpcd. File away.

quote:

Originally posted by dpcd:
Took a fairly new Nicholson Flat Bastard File. ......

All this proves that files are very hard and these Mauser receivers are not as hard as the file on the bottom of the ring. Proves nothing else.

Proves your new file lies just as much as my well used one. lol

quote:

Originally posted by Russ Gould:

Not unless is was poorly quenched, or annealed after the quenching. You cannot file as-quenched case hardened mild steel. You can stone it, or use a diamond abrasive. This is what the English trade referred to as "hard fitting", which was necessary to correct warpage if it occurred.

The fact that you can file on a Mauser receiver in the hardened areas demonstrates that either the case hardening process failed, or that it was annealed (this is a "process anneal" not a full anneal which would leave the receiver dead soft) after it was hardened. This is indeed done most of the time.

I do case hardening myself and I always use a file to test for success. If the process was followed correctly, you CANNOT FILE CUT THE PART when it comes out of quench. And then I anneal at 425 to prevent the case cracking or flaking off. The latter is what explains why some vintage guns have a condition that looks like flaking chrome plating on the receiver: it's not chrome or nickel, it's the case flaking off.

I don't mess with through hardening as you have to control the process rather carefully, following a prescribed time/temperature curve, and in most cases you need an inert atmosphere. Other than springs and screws, that is, I make a lot of those, using the appropriate through-hardening alloys.

So when you say you can cut "case hardened steel", it's really annealed case hardened steel.

The term is tempering, and the case hardened receivers were tempered after quenching.

So unless you were at the factory and file checking them after quenching and before tempering a file will cut them.

quote:

Originally posted by Russ Gould:
Heat Treatment 101

If you look at your link address, the last word in that address is tempering.
www.efunda.com/processes/heat_treat/images/ Tempering..

And that image appears in this article on the same website.
https://www.efunda.com/process...tening/annealing.cfm

Process Annealing is used to treat work-hardened parts made out of low-Carbon steels (< 0.25% Carbon). This allows the parts to be soft enough to undergo further cold working without fracturing. Process annealing is done by raising the temperature to just below the Ferrite-Austenite region, line A1on the diagram. This temperature is about 727 ºC (1341 ºF) so heating it to about 700 ºC (1292 ºF) should suffice. This is held long enough to allow recrystallization of the ferrite phase, and then cooled in still air. Since the material stays in the same phase through out the process, the only change that occurs is the size, shape and distribution of the grain structure. This process is cheaper than either full annealing or normalizing since the material is not heated to a very high temperature or cooled in a furnace.

^ None of that applies to a Mauser receiver after case hardening and quenching.

But this does from the same website.
https://www.efunda.com/process...tening/tempering.cfm

Tempering is a process done subsequent to quench hardening. Quench-hardened parts are often too brittle. This brittleness is caused by a predominance of Martensite. This brittleness is removed by tempering. Tempering results in a desired combination of hardness, ductility, toughness, strength, and structural stability.

When I tried to open the link it says it is a potential virus and advises me not to go there.

A good explanation of the different processes and goals.

Process
Annealing: Annealing process involves the heating of a metal to or near the critical temperature followed by cooling to room temperature very slowly in an oven.

Hardening: In hardening process, the metal is heated into austenitic crystal phase and then quickly cooled.

Tempering: Tempering is done by re-heating the metal alloy to a temperature lower than the critical temperature, holding for some time and cooling.

Purpose
Annealing: Annealing softens materials.

Hardening: Hardening increases the hardness and strength of materials such as metal alloys.

Tempering: Tempering reduces the brittleness of metals.
https://pediaa.com/difference-...ening-and-tempering/

The purpose of annealing a hardened receiver is so that further machining, engraving or working such as straightening can be done.

The purpose of tempering a quench hardened receiver is to reduce the brittleness and reduce the possibility of catastrophic failure.

In all the years ( decades ) I have been gunsmithing.

I have found one Mauser pre WW1 receiver that I could not file. It is a FN receiver made for Brazil model 1894. The dang rear bridge is so hard that a file would start to dig in, and then skip, had to grind most of the rear bridge down then polish it as I ruined a new 10 inch file trying to blend things in on the rear bridge.
Dang receiver was very hard to tap for scope mounts as well. Its still in my shop right now for a stock job.
No set back what so ever in the lug seats

Have converted lots of 1935 Chilean Obendorf actions over the years, those actions are TOUGH, can not do much cutting on them with HSS cutters, its a Carbide end mill cutter show.
Yet can file the outside of them, and tap them with a HSS drill and tap.

Have filed on lots of 1914 Enfield actions over the years as well.
Its interesting to use a carbide end mill to recut the reed rails of a 1914 Enfield and see the middle section is softer than both ends.
Now the 1917 receivers are yet another story as they had a different spec on the heat treating

Yes its a big difference between a carberized, then tempered surface action, or a thru hardened and tempered action.

Just my 2 cents
J Wisner

[quote]Took a fairly new Nicholson Flat Bastard file.
Did you try an old round sun of bitch?

No but I can if you want to pay for another round of file tests. I have a few old round SOBs in my file rack.

This discussion reminds me of "Should I break in my new rifle barrel, and if so, how do I do it ?

Yup. If you'd dragged as much stuff out of a heat treat oven as I have over the years, it's time to go get some more popcorn......

Are you the Mike Rowe from "Dirty Jobs?"

quote:

Originally posted by Mike Rowe:
Yup. If you'd dragged as much stuff out of a heat treat oven as I have over the years, it's time to go get some more popcorn......

Mike, it would be nice to hear what your experiences have been. We are all still hungry for knowledge.

I wish I was the guy from dirty jobs, sometimes.

I bet it pays better than working on guns and gun stuff.

Oh well, I'm "retired" from that now.

But my thoughts on Mauser actions....

I think Jerry Kuhnhausen said it best. A lot of Mauser's design was based around the limitations of the materials available, and processes of the day, i.e. the steel and how to heat treat it so everything stayed in one piece. I think he did a helluva job. If I had to have one rifle to stake my life on, it would be a Mauser 98.
The problem with the bulk of the actions we have today, is not so much what was done at the time of manufacture, but what's been done to 'em since. There are lot of people out there, who, as the Gipper used to say, know so much that just isn't so.
You just don't know what's been done to them, so you have to start from scratch so you know for sure what you have. Which means a full anneal and re heat treat by someone like Blanchards who have figured it out. You can bandy all the Rockwell numbers and case depths around you want, but it's all a guess.
In the scheme of things, it does not cost much at all to do it right.
The modern process is so controlled, this makes sense. Heat treatment in Mauser's time was basically witchcraft. Unfortunately, that's the way some people still insist on doing it. Metal heat treatment is a known science, so why not use it? You don't have to hold your mouth right any more.
I have almost always had good success heat treating steel. I use virgin certified alloys so I can select the right one for the job, and know exactly what to do to it so the right outcome is ensured. To do anything else would be a dumbassed waste of my time.
I have never heat treated an action - I'm not equipped to do so. The job is sent out to someone who is, and who know's their business.
A man's gotta know his limitations, you know.....

Since you mentioned cost, it is $179.

Be happy to pay it.

pretty sure most military contract Mausers were selectively case hardened.

I've done it using copper plating and stripping it where I wanted the case to take during carburizing.

I've NEVER seen a Mauser that wasn't.

Burgess had some good info on this. Maybe Mike will chime in with it.

FN, GMA and Interarms are not what I group as Mausers in the post above. Even though they are built quite similar to System 98.

Farbedo:

Back in '65-66 running a lathe for a living.
I had a stack of 3" thick x 6" dia heat treated
rings to turn into cones.

They just ate HSS bits right up.
Carbide cut 'em just fine.

The sharp edge only had to be 'radiused/broken over".
I made three passes with a Nicholson 14" file.
Am just guessing it was medium fine.

Nothing came off the edge. WTH? Turned the file
over and was going to hit it again. DAMN!
Three grooves 1/16" deep cut into the file.

Called the foreman over. He went to the crib
and got a new file and hit it a couple licks.
Sure as hell, cut grooves in that one too.

"send 'em back to heat treat to be annealed, we
can't waste time working on such material".

Any idea how hard that may have been? I've
done the same damage a couple times with my
own tempering here in my own shop with tools
I've made from drill and sucker rod material.

As hard as files are, they're not the hardest
steels around and you don't need carbide to
cut 'em either.

Comments welcome as I'd like to know more.

thanks,

George

quote:

Originally posted by gunmaker:
pretty sure most military contract Mausers were selectively case hardened.

I've done it using copper plating and stripping it where I wanted the case to take during carburizing.

I've NEVER seen a Mauser that wasn't.

Burgess had some good info on this. Maybe Mike will chime in with it.

Absolutely correct, it's a fact that a lot of people can't or won't grasp.

They take a Rockwell reading somewhere on the exterior and declare "it's soft!". Not to mention the RC scale is not really suitable for testing low carbon steel, you need to use Brinell.
If you could test it in the lug seats then you would have some useful information, but I believe it's almost impossible to do so.

I'm not saying lug setback doesn't happen, I've seen it a few times. Whether it was operator error, just wear and tear or too soft, who knows.

In the meantime I'll just use sensible handloads in cartridges they were designed for and not worry. You do have to consider the different burning characteristics of modern powders though. Stay in the 50K range and you are safe.

If anyone knows of a heat treater in Australia that you could trust to re-harden a Mauser, could you please let me know. I might consider it if I wanted to build a .270 or something.

George you didn't say what material your rings were made from, nor what "heat treating" was done to them. Which is the crux of this whole discussion; there are literally infinite possibilities that fall within the definition of "heat treat", a term which means nothing in and of itself. One possibility out of 1000 is that your steel was 1018 and was carburized and not tempered back to any usable hardness afterwards. Or any number of other things. "Heat treatment" is not one process. Sort of like the term "cooking"; cook a steak like you cook boiled eggs and you end up with crap.
As for modern (post WW2) 98 Mauser pattern receivers; those don't count in this discussion and neither do any modern action made from 4140 steel; those are heat treated, some only induction hardened in the lug areas, and are still butter soft and can be cut with a knife anywhere.
We are mostly talking about a process from the 19th century (actually before that), starting with wrought iron and making the surface hard.
Lots of misconceptions here. As with everything small arms related.

As for set back, I have only seen it on actions that did not have the original barrel on them, or were Interarms 7.65s rechambered for 30-06, or were Spanish 7mms, factory converted to 7.62 CETME, and guys had been shooting 7.62 NATO or 308 Win in them; a much higher pressure. I have never seen an original 7, 7.65, or 8mm military rifle with set back lugs.

I guess we know know who has the hardest file ...