question regarding heat treating ak47 flats

[chadstrickland]

I ordered me two of them from nodakspud which are excellent and I am in the process of two builds. However they claim that heat treating there receivers are a critical step in making the rifle last. I understand that heat treating certain metals will strengthen it as long as it is done properly. You can weaken the metal if done improperly.

My question is this....has anyone here ever heat treated something successfully? And if so how did you do it.

Another question. How much does it really help? Is the metal under enough stress where the heat treatment is needed?


I know that the true ak47 rifle had a milled receiver which would be stronger than the stamped receiver and that what I have is a akm with a stamped receiver. My personal conclusion is that they switched over because of 3 reasons 1 less weight 2 cheaper and easier to mass produce 3 pretty much a mixture of the other two..the stamped receiver could handle the stress and was lighter, cheaper and easier to make.

Just leads me back to my original question. Can a receiver with no heat treating hold up?

[Dfariswheel]

You can find a lot of info on the net about building AK's from flats, including heat treating.

Basically, you have two choices, heat treat the entire receiver or spot harden.

To heat treat the entire receiver requires some better equipment including a special fixture to support and hold the receiver to prevent warping. If you attempt to heat treat it without the fixture the receiver will warp and be ruined.
Buying or building the fixture is too expensive unless you're going to be building a number or rifles.

Most builders spot harden around the hammer and trigger holes. These are the critical areas. This is usually done with a torch.

Here's some info:

http://www.surplusrifle.com/shooting...uts2/index.asp

[chadstrickland]

Thanks bud..that place is a gold mine

[HiBC]

I am not a lawyer or expert in firearms law.You will want to do your own investigating to find out what is true.
I am suggesting you do some investigating before you make two.When I built my FAL from parts long ago,I recall something about it being OK for me to make one.Something was different about making two.It might have to do with "manufacturing".
If it all comes out wrong,you may have just posted on the internet that you are in the process of commiting a felony.
I am not saying I know that for a fact.Just check into it.

[chadstrickland]

Thanks man ill go check

[chadstrickland]

That was a quick check...when I purchased (well I say I purchased I ment that the gun shop did ) the nodakspud receivers I had to fill out the same 4473.. paperwork like when you buy a rifle. Because they came from the company with serial numbers on them.

However I was reading a post on the high road that was quoting a letter from the batfe and they said it was legal as long as you put a serial number on it, was not full auto or sbr or aow, and that you was building the rifle for yourself and not with the sole intent to sell it. The above is for bending your own flats and such.

What I have done is the same as buying a completely assembled rifle.

[brickeyee]

I am suggesting you do some investigating before you make two.When I built my FAL from parts long ago,I recall something about it being OK for me to make one.Something was different about making two.It might have to do with "manufacturing".

You can build as many as you want, but only for yourself.

The issue is with building and selling them.

[mkk41]

I'm a toolmaker and had done heat-treating for almost 30yrs. In order to properly heat treat any steel , ya have to know exactly what alloy or analysis it is.
http://www.cartech.com/toolsteelspowder.aspx

It's no where near as simple as "heat till cherry red and quench in water or oil".

Each alloy has it's own protocol , such as oven atmoshere , oven preheat , 'critical temp' , soak time , and quenching specs , whether in air , oil , water , brine , etc. And 'oil' means specially formulated quenching oils. http://www.houghtonintl.com/images/H...0quenching.pdf

Critical temp can be anywhere from 1500-2800 degrees. And by 'critical' , they mean no more than 25 degree error.

Wrong temp and quench and you can very easily 'burn' or otherwise damage the grain structure , making the piece too soft , too hard/brittle or otherwise improperly treated.
Then there's distortion and warp.

Anymore , it's best left to commercial heat treaters. We use Solar Atmospheres.
http://www.solaratm.com/

[chadstrickland]

Hmmmm...yea I have lost the desire to heat treat stuff. I think I could probably find a company to do it for me. If not then I will just shoot till it falls apart then bend a new one.

I feel comfortable using a lathe, milling machine, band saws and such I just don't feel comfortable with the whole heat treating stuff, especially all that stuff about using cyanide crystals and such

[Gunplummer]

I agree with the other guy.I was in machining/tool&die a long time. If you don't know the material, don't even start. The Chinese did not even heat treat the trunion block on their AK's and pinned the barrels on. They were crap but did not blow up. They just slowly cease to function. They don't know how to heat treat and stayed away from it because it would have been more dangerous to do so than not.

[Bill DeShivs]

Heat treating doesn't require cyanide.
The method of heat treating in spots with a torch can not work, unless the entire receiver was hardened to it's maximum hardness. Then, you could spot-anneal with a torch.
I doubt an AK receiver would benefit much from even proper heat treating.

[Harry Bonar]

Sir;
You must know the number of the steel you are heat treating before you even consider it!
Harry B.

[mkk41]

QUOTE "Heat treating doesn't require cyanide."

Cyanide was used to surface harden (and blue) low grade steels 150yrs ago.

[Dfariswheel]

The reason home builders spot harden AK flats is to prevent the hammer and trigger holes from wearing to an egg-shape, which they will do if not hardened.

What you're dealing with here is a piece of sheet steel that really requires hardening in only the pin holes. While rather crude sounding, it's an entirely suitable method of building an AK rifle from a flat steel receiver blank.
This IS the accepted method for home builders and a lot of AK's have been successfully built using this method
If the receiver hammer and trigger holes are spot hardened the rest of the receiver can stay in the soft state since it's under little stress.

Without the heat treating fixture and equipment, full receiver heat treating as done by AK factories is beyond the home builder.
While you do need to know your stuff and the metals used to heat treat most things, the makers of AK flats use a steel designed be spot hardened as shown on the link posted.

Again, while this sounds crude, there's many thousands of nice AK rifles out there that were built using the pin hole hardening method.
It was even used by Ohio Ordnance to build their older receivers.
Military AK receivers are fully heat treated, and so are the better American made commercial receivers like the Global Trades/Elk River, and the top of the line Nodak Spud receivers.

[Bill DeShivs]

DFariswheel,
The link you supplied doesn't work.
The only steels that can be spot hardened in multiple places with a torch are air-hardening steels. It doesn't work on 4140.

[chadstrickland]

Once again I find myself doing serious research on a project

But there is nothing like listening to the real professionals discuss the topic in question. The value of websites like these are priceless. Thanks for all the help folks.

I bet the owner would disagree lol

[HiBC]

Agreed you need to know what steel you are working with.Common rolled steel,such as 1018,you just won't get anywhere heating and quenching.You might be successful using Kasenit and Templac.
If they used something like 1095 spring steel,eyeball spot treating may work out.Plenty of springs have been eyeball heat treated.As a matter of fact,IIRC,one of the causes of heat treat problems was described in Hatchers Notebook:Someone decided all the windows in the arsenal needed washing.The change in ambient light de-calibrated the heat treater's eyeballs,and overheated,brittle steel resulted.I have built Siler muzzle loader locks that require the hammer,sear,and maybe a couple other parts to be old school red/quench/draw to color heat treated and they came out great.
Its not quite true that spot hardening isn't used with proper steels.I worked for an industrial controls outfit,in their heat treat area I was filling in.Some castings had a cam area that needed to be hard.I used an induction machine,I would postion the part,hit a switch,the part was heated in a spot for a number of seconds,then I dropped it in water.Destructive testing was done,sample parts were sliced then ground and polished.The hard section could be clearly seen.I believe these were a 41xx or 43xx steel.Some military 1911 slides were spot hardened in the lug area,and the heat color can be seen.Mauser bolt receivers are often claimed to be soft.Some are.Most are soft in much of the receiver,but they are spot hardened at the locking lugs,extraction cam,etc.

[chack]

there is no prohibition against selling a rifle that you assemble unless you do so many that it appears that you are acting like a dealer. Then the prohibition is against dealing without a license.

The prohibition to be concerned about with AK 47s is when you are manufacturing a reciever. You can't manufacture a receiver for resale without a license.

[Bill DeShivs]

With any high carbon steel, you would have to heat the entire receiver to critical temperature, and quench it, then either temper the entire part, or leave it hard and spot-anneal with a torch.
Carbon steel (other than air-hardening steel) must be fully hardened, and then drawn back (tempered) to whatever hardness you want. You can't heat it a little and make it harder-only softer.

It would be impossible to heat all the individual areas at the same time and keep them at the proper temperature until quenching.

[Dfariswheel]

The Surplusrifle.com site seems to be down right now. It'll be up again soon.
It has pictures of the spot hardening process for AK receiver holes.

Here's other sites with spot hardening instructions:

http://www.akparts.com/akinfo10.html

http://www.quarterbore.net/forums/showthread.php?t=522

[Bill DeShivs]

DF- there is some very bad information there!
While you are heating hole #2 to red, you are already annealing hole #1, etc. etc.
4130 & 4140 won't harden enough to make a file skate.
I would just harden the whole receiver, then temper if necessary.

[Gunplummer]

If you heat 4140/4130/4150 cherry red and throw it in water as previously mentioned, it will get like glass. If you spot heat it and throw it in quenching oil you will get spot hardening up to 58-60 RC. Do not use water. I have made a lot of high power rifle bolts and I sit behind my work. I find it hard to believe that they use Chrome Molly on receiver flats to begin with.

[guncrank]

If you purchased two receivers from Novspud , they are already heattreated.
Just assemble them.

[chack]

what guncrank said

[chadstrickland]

I know the nodakspud are heat treated. Lol the reason I asked the question was because I was interested in bending my own flats for my future builds. Not that I have a problem with nodakspud as there receivers are superb I just wanted to try my hand at bending