Home Forums Hunting & Shooting Gunsmithing Black nitriding question

H&M quoted me $250 plus return shipping of about $35.

By the way, are there steel parts that shouldn't be nitrided? H&M says no springs, titanium or aluminum. I'm thinking here of scope ring screws, assembly & pivot pins and tiny setscrews. I want to get all of the visible (and most of the internal) parts treated so it's uniformly the same color and smooth up the action in the process. Seems like there's not much reason to harden scope ring screws with the treatment, but maybe I'm missing something.

Huh, in the Video H&M guys say that they do the corrosion protection bath after the nitride bath.

Just heard back from H&M about the small parts: "Do not nitride the firing pin unless you know the material and the hardness." But they said all the other small parts were fine (except springs). Here's hoping my action will be almost as smooth as a Krag when they get through with it

My guy in Phx does mine for $60

Care to share?

Phoenix Heat treat

I think you have to do off in person

I see they offer "gas nitriding". How is the finish compared to the salt bath QPQ process?

Most guys charge 60 bucks just to tear down and re-assemble a firearm these days... so I’m assuming you sent him parts.

Interesting that Nitriding is normally done after stress relieving, and then it does add a 1/2 a thousands according to this link .

https://www.metlabheattreat.com/nitriding.html

You don't know what you are talking about.

I see from the link above that they are really heating the part enough to ruin the heat treat. For reference, the correct temperature to draw a spring is about 750*F. A tumbler is drawn to about 450*F. Depending on the exact alloy a 4140 receiver would be drawn to a temperature somewhere in-between those figures. Heating a receiver to 1000*F and cooling it slowly would result in a dead soft state. When fired the locking lugs would set back making it impossible to open the bolt. I would not let them touch my rifle on a dare.

For items that are not heat treated, like pistol slides and frames I see no issue.

You should really stop talking out your a$$ while you can. We are not making springs. 1000⁰ F does not make steel " dead soft" I've been making knives and guns for many years. To make steel dead soft you have to heat it until it reaches critical temperature. This is the point at which it quits being magnetic. Depending on the steel 1800-1900⁰

I called and talked to Glen Harrison ( Defiance machine- Phoenix machine at the time) he told me it was ok to salt bsth his action to 1000⁰. His temper was about 1070⁰ f. The added hardness of the surface would make up for a lost point in temper draw back.

With 4340 or similar Chrome- molybdenum steels this is fine. I have nitrided dozens of actions. I disassemble them and only send the parts i want treated. No springs or pins. They come back tougher than he'll and corrosion resistant.

ALL Glock slides are nitrided. I suspect they know something about metallurgy.

I don't like what it does to the bore. I've had 2 barrels that shot poorly after nitriding. I won't do any more barrels.

Ok, springs I get. Are most pins already hard enough because they're made out of something like drill rod stock and heat treated to begin with?

I beg anyone who is thinking about heating an action to 1000*F during a nitride process to contact the manufacture of the rifle before they proceed.

Per the heat treating chart for 4140 steel heating to annealing to 1000*F severely weakens the yield and tensile strength. This is serious stuff, if an action fails you can die.

https://www.practicalmachinist.com/...-special-application-4140heat_strain.jpg


https://www.snipershide.com/shooting/threads/to-nitride-or-not-to-nitride.6252625/
Where the nitriding becomes relevant is that in this instance, as in: When you step on your crank and make a mistake like this, the action does not merely split apart and lock up the bolt. It goes BOOM and gun parts become shrapnel.

I'm sure glad that you don't want yours done. One more out of the waiting line. Yes, I started having this treatment done about 20yrs ago and ain't had a problem yet.

Literally millions of guns have had this treatment.

Yep, he's a liberal for sure- worried about everything

Noting like being insulated by a stranger who does not have a clue what he is talking about.

Fact, not a liberal........

Fact rifle actions are heat treated for specific properties such as strength and durability. The heat treatment temperature are specific to the alloy.

Fact, the nitride process is a newer form of case hardening. The the high heats involved changes the manufacturers' heat treatment of the bolt and action. It can create a much harder core that originally intended my the manufacturer. It depends on the steel used it make it in the first place. If you do have a failure, say due to a bad reload, a brittle action can grenade and kill you. A a brittle bolt can shed it's lugs and kill you.

Check with the original manufacturer before you do this. That is all I am saying. This is not some obscure theory I pulled out of my ass. It is basic knowledge that anyone worthy of the title "gunsmith" should know.

20210319

First chart shows tempering range and colors for temps.

Second shows effects of temp on hardness.
Notice temps in first for tempering.


Second is for drawing knives made of 1095 back from brittle hard
To the range of normal knives. Softened, but still hard.

No idea how nitriding affects a gun.
But there is some BS being thrown around here,

And Scota is not wrong in his talk of temps.

The wild card in this is the post treatment time and soak time.

In my younger years I worked for a metalurgist in spokane by the name of Bob Williams. Bob owned Pohl spring works and I did what I could to pry knowledge from his head.

While it is true that the 1k will potentially affect the draw, we don't know the potential carbon migration, chill slope....etc.

There's obviously some surface hardness increase but at what cost? If anyone is curious, treat a recoil lug and make varying depth of grind across one side. Smack it in the tester and see how much if any change in RC is had....and how deep.

I don't recall exactly what our time and temos were for drawing 4140, but 4 hours at 600 rings a bell. A rifle action is no where close to that hard.

I knew it would get a reaction

You are winning about a treatment that thousands use with no issues yet you persist to belittle us