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View Full Version : Metal Question, Cold Vs Hot Rolled


sterno
June 24, 2009, 08:12 PM
From what I've read, you'd want to use cold rolled steel for making gunparts. Can you use Hot rolled at all or is the carbon content too low?

If the proper heat treatment was used, could you use hot rolled steel to fabricate gun parts?

dahermit
June 24, 2009, 09:37 PM
From what I've read, you'd want to use cold rolled steel for making gunparts. Can you use Hot rolled at all or is the carbon content too low?

If the proper heat treatment was used, could you use hot rolled steel to fabricate gun parts? Cold rolled steel is low carbon steel. Hot rolled steel is also low carbon steel.

"Cold rolled" steels is made from hot rolled steel by running it through rollers to break up the oxides on the outside and then "pickling" it in acid to remove the deposits. Cold rolling breaks up the grain structure of hot rolled steel. Some old time machinists preferred hot rolled steel because they felt the grain structure provided more strength than cold rolled.

Heat treating (hardening, drawing) to produce strength is dependent upon enough carbon in the steel to allow it to change from ferrite into austinite and then in to martinsite. Neither hot or cold rolled steel has enough carbon to do this. They can however become "half hard" with a sub-zero quench (liquid nitrogin...not likely to be used outside a lab or a manufacturing facility). Both can be "case hardened" by heating to red heat and adding carbon with some product like Kasinite, but this will only produce a hardness that is only a few thousandths thick.

Cold rolled steel is easier on machining cutting tools than hot rolled, unless you get underneath the oxide on the first cut.

Most gun parts require some degree of heat treat or require some property that prohibits the use of cold or hot rolled low carbon steels for most gun parts, but not all.

sterno
June 25, 2009, 09:00 AM
So what kinds of steel should I look for?

Pocketfisherman
June 25, 2009, 10:10 AM
Cold Rold is also significantly harder on the Rockwell scale then Hot Rolled. The surface is less porous, slower to oxidize, but it is also more brittle than hot rolled. A lot of parts are made from hot rolled because it is a lot easier to bend, cut or machined, and then heat treated after the fact for hardening. It does not much matter which is used, it is the end result of the product, and quality put into the manufacturing and/or hardening of the parts during that process. Cold Rolled can also be annealed to soften it, machined, and then hardened again too, but that's expensive in terms of the energy costs to do so.

dahermit
June 25, 2009, 05:26 PM
O-1 (oil hardening drill rod), W-1 (water hardening drill rod), are the too most common that can be hardened and drawn to the desired amount of strengh and hardness.

http://www.onlinemetals.com/steelguide.cfm

You want tool steel:
http://www.onlinemetals.com/toolsteelguide.cfm

dahermit
June 25, 2009, 05:38 PM
Cold Rold is also significantly harder on the Rockwell scale then Hot Rolled. The surface is less porous, slower to oxidize, but it is also more brittle than hot rolled. A lot of parts are made from hot rolled because it is a lot easier to bend, cut or machined, and then heat treated after the fact for hardening. It does not much matter which is used, it is the end result of the product, and quality put into the manufacturing and/or hardening of the parts during that process. Cold Rolled can also be annealed to soften it, machined, and then hardened again too, but that's expensive in terms of the energy costs to do so. Common 1018 cold or hot rolled steels cannot be hardened, come in a soft state...does not have to be annealed, or can it be.
See links above relative to hot and cold rolled steel and the carbon content. Steels that contain .20% carbon will not harden with heat and quenching with normal means.

Tool steels (which can be heat treated) are not usually refered to as: hot or cold rolled steel.

Scorch
June 26, 2009, 12:39 AM
Depending on what part you are trying to make, 4140 may be your best bet.

sterno
June 26, 2009, 09:23 AM
I found an online supplier that answered alot of my questions. Thanks for the responses!

I'm pretty familiar with metalworking/blacksmithing/foundry processes, I just don't know that much about the different steels. All the stuff I've worked on before didn't really call for anything special so I just used hot rolled.

kraigwy
June 26, 2009, 10:34 AM
So what kinds of steel should I look for?
__________________

Between the two, Hot Rolled, like mentioned, it has more carbon, you need the carbon for any type of heat treating which most gun parts need.

sterno
June 26, 2009, 01:20 PM
Ok, so let me speculate for a second...

Lets say I was going to fabricate every part on a single-shot pistol chambered in a low pressure round, like say, .22lr.

Would it be safe for me to use hot rolled steel, case hardened, for the internals (Hammer, sear, trigger, firing pin, etc.)? Would I be safer using tool steel for the barrel and breech block?

Bill DeShivs
June 26, 2009, 01:23 PM
You would be safer using tool steel for all the parts. Most makers use 4140.

sterno
June 26, 2009, 02:05 PM
Is tool steel always oil-quenching or is there water or dual-quenching version? Is there are, which is superior?

I really appreciate all the info!

asskickinpeanuts
June 26, 2009, 10:29 PM
My understanding of steel (at least sheet):Carbon content is a function of the heat/grade (or recipe) of the melt for the steel at the mill. Hot rolled is softer because the grain structure is haphazard. Cold rolling aligns the grains, which is called work hardening, which increases the stiffness. Annealling after cold rolling allows the grains to randomly re-orient themselves. Thus, dead soft or fully annealed is soft like hot rolled. Tempering allows a certain amount of hardness to be imparted back to the steel, making it harder, depending on the amount of elongation after annealing.

Folks have made careers out of studying metallurgical properties and how to get them for different applications. More specific questions will indicate more specific answers. And yes, this opinion may be worth what you paid for it.

Zilmo
June 26, 2009, 10:31 PM
You would be safer using tool steel for all the parts. Most makers use 4140.

4140 is not tool steel. It is an alloy steel commonly used in airframe products along with 4340, but it is not a "tool steel".

grymster2007
June 27, 2009, 02:37 PM
I wouldn't use hot or cold rolled steel for most gun parts. High strength alloy steels such as 4140, 4340 and 4350 and many others would be appropriate for most parts. Tool steels, such as O1, A2, D2 might be good choices for parts subject to wear, but not practical for most applications.

dahermit
June 27, 2009, 03:03 PM
Is tool steel always oil-quenching or is there water or dual-quenching version? Is there are, which is superior?W-1 is water quenching tool steel. If you quench it in oil rather than in water, it will not harden as much as if quenched in water. O-1, if quenched in water, is very likely to produce quench cracks and should only be quenched in quenching oil.

Water is a more sever quenching medium than oil. W-1 Steel, although intended to be water quenching, often will have quenching cracks and distortion even if you use the correct temperature for hardening (1333 degrees F.), and drawing.

brickeyee
June 27, 2009, 03:22 PM
Tempering allows a certain amount of hardness to be imparted back to the steel, making it harder, depending on the amount of elongation after annealing.

Tempering is performed after quenching to soften the steel slightly from the very hard (and brittle) quenched state.

Without tempering it is possible for steel to be very hard but brittle to sharp loads.

Tempering is done by heating to a controlled temperature and allowing slow cooling, or sometimes another quench but at a lower temperature.

dahermit
June 27, 2009, 08:29 PM
...Tempering allows a certain amount of hardness to be imparted back to the steel, making it harder, depending on the amount of elongation after annealing...With all due respect, this statement is completely ignorant babble. What tempering is, is giving up some of the hardness for the advantage of toughness. The person making that statement has not studied metalurgy in college (more likely in a bar).

bustoff
June 28, 2009, 08:23 AM
first, im not a metallurgist nor a gunsmith, just a lowly machinist. hot or cold rolled material is just how the material was formed and does not tell you what type of steel you have. cold rolled steel is most commonly the 10xx series steels,1018, 1020 and so on but that type of steel can also be hot rolled. see how it works? you choose the proper TYPE of steel for the job. everything ive read shows alloy steel,4140.4340 and 17-4 and 400 series stainless is used firearm parts, maybe a real gunsmith could verify this. by the way I do pretend to be a gunsmith but only on my guns:D if you are really interested in the applications for the different types of steels get yourself a copy of the machinerys handbook. enough information to make your head explode, just try to get a used copy cause new ones are expensive.

grymster2007
June 28, 2009, 10:42 AM
The person making that statement has not studied metalurgy in college (more likely in a bar). It's metallurgy.... two ells!.... pick up yur English in a bar didja? :D :p

dahermit
June 28, 2009, 06:05 PM
It's metallurgy.... two ells!.... pick up yur English in a bar didja?
__________________Your attempt at humor not withstanding, this is a discussion about the properties of steel. In that note, please feel free to list any errors I have posted in that context. I will be sure to click on spell check in the future.

Unclenick
June 28, 2009, 06:47 PM
Sorry to see this has become contentious. I'm also sorry I'm not at home, where I have a couple of good little books on heat treating for model makers and engineers at the model shop level (small scale). They would be about right to recommend, but I read them so long ago the titles elude my memory.

Cold rolling steel does work harden the surface of the metal, and the stresses this sets up do distort the metal over time if you don't anneal it before machining it. Don't ask how I know? The bottom line is you can't make carefully fitted parts from it unless you anneal it first. It is strong enough that you can make things like wear-resistant pins from it if you case harden them afterward. Then you get a hard surface, but a malleable core to resist shock.

Hot rolled is usually sold as weldable steel because it doesn't pull and distort as badly (because it doesn't have those surface stresses) much when you put the parts together. I usually use it for things like match sight hoods for the Garand and M1A. Items where hardness and toughness aren't at all critical.

As to the numbered steels, a great web resource is matweb.com (http://www.matweb.com/). It will give you a full of the properties of the materials in many instances, and even if you don't understand them all, you can do some comparing there.

It is worth mentioning that water-hardening steel is usually quenched in 9% brine solution rather than plain water. This reduces the chances of surface cracking. Nonetheless, the high stresses in quenched water-hardening steel usually distort it some and you have to play games with it sometimes to remedy that.

Whether water or oil hardening steel is used, after quenching it needs to be tempered or the stresses can start cracks. Just-quenched steel is called "dead hard". The worse case is the higher stress brine-quenched steel which can start cracking in as little a couple of hours in some shapes. It is not unheard of for someone to quench it then forget and leave it sitting for a few days, only to go back and find some shattered pieces in place of the part.

To keep dead hard steel from self-destructing, you have to relieve some of the most extreme stress. That is what tempering does. The term comes from the word "temperature". It means to raise the temperature of dead hard steel until it looses a certain amount of stress. The extreme hardness out of the quench is then said to be tempered. It is how that word has come to be used to mean "mitigated" or made less extreme.

With the exclusion of the 500 to 700 degree range, where, perversely, common carbon steel can become more brittle rather than less, it is generally the case that the greater the temperature is that you expose the steel to, the less hard it becomes and the tougher it becomes. Toughness is determined by impact testing. Hammer heads, for example need to be hard enough that striking nail heads doesn't batter or distort them, yet tough enough not to break. That combination tends to occur at around a Rockwell C scale hardness of 50. While the exact temperature a quenched steel needs to be raised to in order to temper it (also called drawing the steel back form dead hard) to RC-50, for most carbon steels it is in the vicinity of 800-850 degrees or so.

Thus, to heat treat a batch of hammer heads, a typical process might look like this: heat them to the quenching temperature, which might be 1500 degrees for the alloy (but is reduced as the carbon content increases). You hold it at that temperature in the oven for an hour per inch of thickness of the steel to let the heat "soak" into the steel. With professional equipment this is done in a hydrogen atmosphere both to speed up the transfer of heat to allow a shorter soak time (say, half an hour per inch) and to avoid heavy oxidation of the steel surface (slag). The steel is then quenched, leaving it dead hard and under great molecular stress. It is then taken dead hard from the quench and placed in another oven and the temperature is raised to 800-850 degrees, and again the steel is allowed to soak at that temperature for the same amount of time the pre-quench heating required. It is then cooled again.

If, instead of hammer heads, you had wanted to leave enough stress in the steel for it to act as a spring, the drawing temperature might be more like 450 degrees. If you wanted enough left to make a cutting tool, like a D-reamer, it might be as low as 300. Again, it depends on the steel composition and the manufacturers of drill rod and tool steel stock will provide a quench temperature and a list of temperatures for drawing to different Rockwell C scale hardness numbers.

I've provided a copy of MSC's catalog page with general quenching temperature and temper information on common drill rod and steel flat stock. Also something on the 500 degree embrittlement range.

mwlu711
June 28, 2009, 08:28 PM
alot of your specalty steel supliers have books that tell you anything you want to know about the alloys.pacific machinery and tool steel out of portland oregon is good place.

grymster2007
June 28, 2009, 09:02 PM
Your attempt at humor not withstanding, this is a discussion about the properties of steel. In that note, please feel free to list any errors I have posted in that context. I will be sure to click on spell check in the future.I happen to agree with you on the metallurgy front. The humor (or attempt thereof) was all in good fun and meant to demonstrate that we're all human and know not everything.

14cm
June 29, 2009, 06:52 PM
I know this, if my purchasing manager ever orders 200 feet of 2x2 cold rolled solid again for spreaders in the fab shop, i will choke her. it was a wee higher than hr.

customizedcreationz
July 4, 2009, 11:10 AM
Some interesting info here.

brickeyee
July 6, 2009, 11:02 AM
I know this, if my purchasing manager ever orders 200 feet of 2x2 cold rolled solid again for spreaders in the fab shop, i will choke her. it was a wee higher than hr.

Probably received an 'atta boy' for saving a few $$ on material costs, only to eat up more $$ on tooling and labor.

HiBC
July 6, 2009, 02:54 PM
I have a few suggestions.

As someone else mentioned,steel suppliers often will have a reference book describing steels.

McMaster-Carr is an outfit that sells reasonable sized lengths of alloy steels.

8620 is an alloy one might select for firearms parts.That is what a Garand reciever and many other gun parts are made of.Reasonable hardness can be achieved through a heat/quench/draw process,and it takes case hardening.

P-20 mold steel,and ETD 150,and ETD 180 are pre-hardened as I recallto about R 24-28 C(this is a ballpark number,I am not checking refs)
Now,thisis about as hard as 1911 frames and slides.ETD stands for Elevated Temperature Drawn,150 and 180 are the tensile strengths(150,000 and 180,000 psi.It is a Ryreson steel.

These steels are quite machineable,and may seve many purposes unheattreated.(Not sears,etc,but maybe a low pressure reciever)

Heating and quenching,along with warping and cracking,are avoided.

Expensive and maybe had to find,17-4 PH is a pretty magic steel.Precipitant hardening,it can get up(by recall) close to a Rockwell 40C by just holding it at 900 f for a couple of hours and aircooling.Please get better info,but this is a lead to send you looking.

I'm pretty sure that is what outfits like Freedom Arms use.

If there is a local plastic injection mold shop,ot if outfits like DME and Manhattan Supply still sell mold components,Core pins a a great resource.They are made of H-13 tool steel,through hard,tougher than a woodpeckers lips,and machineable with carbide Two hardnesses,also.

If themold shop has junk mold plates,some are 4140.

Only S&W and Me
July 18, 2009, 03:29 PM
Too much mis-information here...let me clear a few items....I'm 22 years in the biz Automotive Metallurgist.:D

Cold rolled steel is just what is says, steel cold reduced to provide better dimensional results and a elongated grain structure which provides it higher mechanical properities, especially in the transverse direction - across the grain direction. Typically carbon is low, under .10% but can be bought to higher levels for more strength. Higher carbon is harder and more difficult to form/bend.

Hot rolled is more common steel, like it says, hot reduced to a select dimension and lower strength than cold rolled (cheaper and typically worse surface finish than cold reduced but depends on the final pickling process).

Heat treatable steels are typically .30 and up carbon alloyed for hardenability depending on the section to harden deep (ie 4140, 4340). These are quench and tempered (tempered back to a certain hardness after a full hardening during heating and quenching).

Typically guns parts are nitrocarburized (Melonize/Tenifer etc) to provide a thin hard wear resistance layer of heat treat on the metal to resist scratches/damage and provide some corrosion resistance forming an FeNitride layer....at least my Smith is....

Hope this clears the air a bit;)

dahermit
July 19, 2009, 10:54 AM
Heat treatable steels are typically .30 and up carbon alloyed for hardenability depending on the section to harden deep (ie 4140, 4340). These are quench and tempered (tempered back to a certain hardness after a full hardening during heating and quenching). You should perhaps mention that plain carbon steel (only carbon as a significant alloying element)with .40 carbon(medium carbon steel), cannot be heat treated significantly without sub-zero quench, then only become half-hard. The two steels you mention (4140, 4340) are not plain carbon steel, they are alloy steels. A plain carbon steel must have a minimum of .83% carbon(high carbon steel), to harden completely upon quenching.

Only S&W and Me
July 19, 2009, 06:05 PM
Depends on the steel section for plain carbon steels, but yes,generally do not have the hardenability to through harden. It's all about section and steel hardenability based on chemistry. Actually sometimes, depending on the product, you WANT a softer core and a harder surface to increase fatigue life, thus a fast quench of a plain carbon steel (ie 1030) in beneficial. All depend on what you need....

1040 can though harden if small or thin..(ie rod, plate). Water quench will be sufficient

Where did you get >.83 only can through harden...not true.

dahermit
July 20, 2009, 08:44 PM
Depends on the steel section for plain carbon steels, Steel "section"? If you mean "thickness" of the part, heating in an oven ("soaking") for the prescribed time would negate any perceived problems with thickness.

but yes,generally do not have the hardenability to through harden. It's all about section and steel hardenability based on chemistry. Wha...? In plain carbon steel (no other significant alloying elements besides carbon and iron), the amount of carbon determines if it can be hardened, unless you are talking about case hardening...then carbon is added to the outside.

Actually sometimes, depending on the product, you WANT a softer core and a harder surface to increase fatigue life, "Case hardening."

thus a fast quench of a plain carbon steel (ie 1030) in beneficial. All depend on what you need....

1040 can though harden if small or thin..(ie rod, plate). Water quench will be sufficientHere is a quote from "Machining Fundamentals", John R. Walker, The Goodheart-Willcox Company, Inc., South Holland, Illinois. page 377: "Carbon steel with less than 50 points [.50%] of carbon cannot be hardened."

Where did you get >.83 only can through harden...not true. Plain carbon steel is made up of molecules that form in the shape of a cube with an atom of iron at each corner and an atom of carbon suspended in the center of the cube (body centered). This molecule is called ferrite. If the steel is heated to 1330 deg. F., the carbon atom is allowed to move. If there is more carbon available outside the ferrite molecule, five atoms carbon will take up position on the faces of the atom, and the one in the center will move to one of the faces (face centered). When this change has taken place and there are now six atoms of carbon and the original eight atoms of iron in each molecule, the molecule is now called, austinite. If that piece of metal is quickly quenched in water, the atoms cannot move out of the face centered arrangement (if allowed to cool slowly the molecule will revert to ferrite), and is under stress. This condition is now known as martinsite...it is hard steel (about 67 on the Rockwell C scale). Now if there is not enough carbon to form the austinite molecule, the martensite cannot be formed. Thus, low carbon steel cannot be hardened. However, if there are exactly 83 points of carbon (.83%), there is exactly the correct amount for hardening all the metal into martinsite. There is no way to case harden, inasmuch as if it is heated and quenched, all the metal hardens, and to case harden, it must be heated and quenched (Try to case harden a file(67 Rockwell C) and see what happens).
However, if the metal piece is hardened, and then drawn (tempered) some of the molecules will revert back to ferrite, giving up some of the hardness for toughness and will read lower on the Rockwell C scale.

Only S&W and Me
July 22, 2009, 08:35 PM
Dahermit....I could talk for days on this. :D I'm a full degreed Materials and Metallurgical Engineer who deals with this this stuff everyday for 25 years. This is basic 101 for me. You would not beleive the intense heat treat I get involved with daily. Yes, you can quench out steels with lower carbon and get some hardness. I've even done it with 1020. Thickness makes a big difference. Alloys and residual alloys will contribute. 1040 and up will quench out very nice in a small section. Just today got back from trip hardening 1065 fully in a small part section of .250". Go to SAE and read the hardenability curves (Jominy end quench test). This tells you how deep you can harden.Sometimes we fast quench 1040 in a larger section to "rim" harden and keep the core soft with no carburizing or case hardening.

I have to say, this John Walker (hope no relation) is seriously misleading/wrong in his writing...there are no molecules in steel (atomic lattice) and ferrite is not molecules and hardening not possible under .85, tempering causing ferrite etc etc etc.:confused:

BobCat45
July 23, 2009, 09:11 AM
<diffidence>
go to
http://www.dtic.mil/dtic/search/tr/
and search for monograph 88
one of the hits will be:
Title: Heat Treatment and Properties of Iron and Steel - download it.
Or go direct to http://handle.dtic.mil/100.2/ADA361141 and get it.

Also
http://steel.keytometals.com/default.aspx?ID=Articles

Get MIL handbook 5J at
http://femci.gsfc.nasa.gov/presentations/MIL-HDBK-5J.zip
or http://www.everyspec.com/MIL-HDBK/MIL-HDBK+(0001+-+0099)/MIL_HDBK_5J_139/
and see Chapter 2

Info on the web:
http://www.crucibleservice.com/ and http://www.latrobesteel.com/technical_datasheets.cfm

http://www.msm.cam.ac.uk/phase-trans/2004/Bain.Alloying/ecbain.html
- this is an absolute gem, but not one person in 500 will have the patience for it.

http://www.steelynx.net/
- you could drown if not careful.

</diffidence>

This is offered in the spirit of conciliation, and with the hope that some young person will be interested enough to consider a major in Metallurgy or Materials Science.

People were heat treating swords and other implements long before they had any fundamental knowledge of the processes, and getting excellent results. OTOH I know people who can write out all kinds of wonderful equations, who would be unable to turn an automotive leaf spring into a decent blade. We do best when we balance "book learnin'" with practical experience and knowledge.

Regards,
Andrew

dahermit
July 23, 2009, 12:30 PM
After reading the links provided in the above data sources, I have concluded that: 1) Some of what I have read in text books was in error. 2) Some of what I was taught in college was in error. 3) My memory has faded somewhat (I am 66). Therefore, one should consult the data sources as above as the definitive source of heat treat information.

brickeyee
July 23, 2009, 01:49 PM
The concern over the section size occurs since you can only cool the metal so fast through its surface.

A large section will not cool fast enough in the core, but will slowly cool down.

BobCat45
July 23, 2009, 03:47 PM
brickeyee,

That is exactly right. As Only S&W and Me said, it goes back to Jominy curves. Tip: many steel mills have little "gimme" booklets containing this kind of info. Contact your local rep and ask for one.

dahermit,

I turned 60 last winter and my memory is shot. I don't tell people anything anymore because:
1) I did not understand it perfectly when I first learned it.
2) If I don't use it often, I've forgotten even the little I knew.
3) I'm lazy - if I have to go look it up, I'll read it again so I understand it again, but still just tell where to look it up - people can read and get more from it than I can relate.
4) Once I start talking, I forget where I was going and wind up telling stories about my cats and the cute things they do - nobody wants to hear it.

To get back to reality (guns) - there was a guy in Houston, maybe 10-12 years ago, with a business called something like, Texas Longhorn Arms. He made replica Colt Peacemakers, out of the best-quality, cleanest 4340 he could get. It was 'way overkill, much better than "needed" and probably a bear to machine (very low sulfur) - but he wanted to be "the best" and, as far as I'm concerned, his guns were. My regret is that I was too cheap to buy one, and now he is either retired or passed on and there will be no more of them.

This does not prevent me from fantasizing about guns made from exotic, expensive alloys that would not rust/corrode in anything you would find loose on the Earth (i.e. hydrofluoric acid would take a toll on most nickel-based alloys, so would mixed hydrochloric / sulfuric). These would be overkill but still, real cool (in my opinion).

And I have to giggle when folks express doubts about the quality of the steel in some imported guns. Steelmaking has evolved to where modern steel is so much cleaner (less nonmetallic inclusions) and better, and the chemistry so much better controlled, than the very best steels of the 1940s-1950s that it is amazing. If their QA / process-control people are awake, there is no reason offshore steel should be at all inferior to our best from the golden era (i.e. when the 1911 was new, and the Garand was about to be adopted).

Anyway, time for me to shut up and go back to whatever I was doing... have fun!

dahermit
July 23, 2009, 04:57 PM
And I have to giggle when folks express doubts about the quality of the steel in some imported guns. Steelmaking has evolved to where modern steel is so much cleaner (less nonmetallic inclusions) and better, and the chemistry so much better controlled, than the very best steels of the 1940s-1950s that it is amazing. If their QA / process-control people are awake, there is no reason offshore steel should be at all inferior to our best from the golden era (i.e. when the 1911 was new, and the Garand was about to be adopted).Do you mean that the steel used to build the Titanic was not high quality???!!!

BobCat45
July 23, 2009, 07:47 PM
<cackle> if I can believe what I read on the Internet, that stuff was poor even for its time... and the rivets were worse.

Somebody has a .sig line that says something like, "the Titanic was built by professionals, the Ark was built by an amateur."

Oh - and I looked up Texas Longhorn arms, and I was wrong - it was not 4340, it was 4140. Should have looked before I babbled.

And - was Sam Colt left handed? Apparently the Texas Longhorn guy thought so, because the loading gate on the SAA is on the right side, so you have to change hands to load and unload it. His pistols were mirror images of the Colt - you could keep the revolver in your right hand, operate the loading gate and ejector with your left, and never loose your grip on the grip while reloading. That sounds cool!

Regards,
Andrew

grymster2007
July 24, 2009, 07:55 AM
4340 is a bit harder and higher in tensile strength, but both it and 4140 are easily machined and make for excellent gun parts. I thought I'd make my conversion cylinder from 4340. Probably not necessary, but building something just a little better than it needs to be is kinda fun. :)

BobCat45
July 24, 2009, 08:27 PM
That is because you know how. Someone used to cutting 12L14 all day, and getting paid by the piece-part, would not be so calm about it.

Yes - making it "better than it needs to be" is fun! It drives the Supply Chain people crazy, but when the part is for your project, and you are on your own time, better is better.

http://handle.dtic.mil/100.2/ADA076035 - or Google WADC TECHNICAL REPORT 52-73 and get the .PDF - if you want a good belly laugh. It is from 1952, and describes 4330V - about twice the impact toughness of 4340 when both are heat treated to the same strength. We are seeing it come on-line in the oilfield business now, only about half a century after than the fly-guys got it, but better late than never. I think it would be wizard stuff for barrels and receivers, but only if you are making it for yourself - never get it past the people who know the price of everything and the value of nothing.

Regards,
Andrew