An Engineer's take on S&W.

[Dave T]

First one cracked at the dust cover on both sides at around 2500 rounds, most a handload duplicating 230 Ball. Second cracked at the slide stop cut out, the dust cover on one side and showed a hairline crack at the slide stop hole itself (it had been electroless nickeled) after approx 5000 rounds. The heaviest load shot in it was Fed HydraShok 230s (not +P). The third one cracked on both sides at the mag release and under the thumb safety. It digested the most rounds, about 6500, none of which were heavier than non +P factory.

Dave

 

[deuterij]

Very good information and agrees with everything I have heard about materials. In the oilfield, 4130 is common for good reason. Various Inconel grades (high nickel alloys) are used for non-magnetic, corrosion-resistant applications. Galling of 17-4PH is also well known in the oilfield. Some of these assembled 17-4PH parts (especially large diameter helical threads) seemed welded together when you tried to loosen them. Small bits of material would ball up and fill the space in the thread locking it up.

There was a forum thread about N-frame heat treating a while back. This materials information adds to that. Steel has many mechanical properties (beyond hardness or yield strength) with trade-offs between them. Fracture toughness is hugely important.

 

[H P Bushrod]

Interesting post. Thanks for sharing.

 

[Catshooter]

Thanks for the informative reply DaveT.

Makes me wonder about the life span of my aluminum framed Shorty .45.


Cat

 

[perpster]

DaveT, This is a great thread! Dare you ask your friend about MIM parts?

 

[bubbajoe45]

Thanks for the informative reply DaveT.

Makes me wonder about the life span of my aluminum framed Shorty .45.


Cat

Me too! I have 4 aluminum-framed .45 autos (Sig,kimber,para, & Smith (with Sc)). At most, one of them may have a little over a thousand rounds and I don't shoot +P. Also, thanks again for your efforts DaveT.

 

[Dave T]

My friend cracked the frame of an alloy framed Para Ord some years ago. We discussed alloy frames then as it was about the time I cracked my second or third Commander. His take was that the forged aluminum frames could be expected to digest from 5,000-7,000 rounds. He indorsed the idea that alloy framed guns were intended more for carry than digesting thousands of rounds for years. There is some design consideration there too. The 1911 frame was initially designed to be made of steel. It takes quite a beating which work hardens aluminum. A gun like a SIG, with a purpose built/designed alloy frame will probably hold up longer.

That's all paraphrasing his thoughts, but we discussed this subject (his and my cracked frames) over and over for several years. I'm confident about this being his take on the subject.

Dave

 

[CAJUNLAWYER]

I've only got two lightweights-a 317 and a 337. After reading what your friend had to say, I'm knida glad.
Were the 1970-80 era blued N frames made of that 4130 ?

 

[rayb]

?Sticky?

Please, maybe in the gunsmithing section

Thank you

Very well presented, informative post.

rayb

 

[Catshooter]

DaveT,

Your friends take on the dreaded MIM parts would be interesting.


Cat

 

[Pitdog02]

A thread I saved and read from time to time. Very interesting and I own a 1954 Pre 27 also. I try to memorize it so I sound smart when arguing at the range. Sofar Ive butchered it up pretty badly during battles. Mabye I should just print it and slap a copy on the table when being accosted.

 

[bigmoose]

S&W probably has more experience with broaching than any other company. Incidentally, the cost of broaching machine tools is one reason that revolvers are not common today.

Broaching...Now there is a process that you don't hear much about today. I worked at Remington years ago and have to say that they also had decades of experience with broaching. It was fascinating watching those machines carve out the interior surfaces of the Remington Model 700 receivers. They used broaching for many other applications at the factory also. As impressive was the level of skill and precision of the machinists (or tool and die guys) that worked in the tool shop keeping the broach cutters sharp and tuned.

 

[DWalt]

Some may not be aware that Ruger runs a sizable business in making precision investment castings of all kinds for customers that have nothing to do with the gun trade.

 

[M29since14]

...As impressive was the level of skill and precision of the machinists (or tool and die guys) that worked in the tool shop keeping the broach cutters sharp and tuned.

The skill lies with the tool designer and the toolmaker. Properly set-up, the broaching operation is more or less "push button" simple for the machinist.

The comments about the Aluminum/Scandium-alloy are interesting. Its use in a specific product, for instance, the frame of the revolver, likely requires a good deal of actual testing to know whether the addition of the material has merit or is just a flash in the pan. Presumably, S&W has done that testing and knows whether it serves a purpose, if so, to what extent (cost effective), or whether it is a sales technique that is basically useless from an engineering point of view. Generalizing about the topic may not be very helpful in terms of revolver manufacturing.

It might be nice if manufacturers would give us the benefit of their testing, but if they did, likely a lot of products would never be offered for sale. I have had Commanders all my life and am very fond of them (even though one has cracked), but if someone had told me to expect them to crack after, say, 4000-rounds, I probably never would have bought one. The frame of the SIG 220 seems even more fragile to me. On the other hand, I have seen reports of 220s going 30,000 rounds without failure. In all, there are a lot of pieces in this puzzle and material is just one of them. Nothing tells the story like testing of the actual product.

 

[SweetMK]

Some may not be aware that Ruger runs a sizable business in making precision investment castings of all kinds for customers that have nothing to do with the gun trade.

I actually visited their facility in NH in 1980 when we were sourcing parts for the "NEW" GE CF6-80 engine.

We used a hand-full of investment cast parts.

 

[DWalt]

I actually visited their facility in NH in 1980 when we were sourcing parts for the "NEW" GE CF6-80 engine.

We used a hand-full of investment cast parts.

Back at about the same time I was an engineer working for a company which designed and manufactured various types of downhole oil tools. Pine Tree Castings (Ruger) made many components for us. They made it very clear that even though we were good customers, there would be no "special deals" on Ruger guns.

 

[Old TexMex]

Broaching...Now there is a process that you don't hear much about today. I worked at Remington years ago and have to say that they also had decades of experience with broaching. It was fascinating watching those machines carve out the interior surfaces of the Remington Model 700 receivers. They used broaching for many other applications at the factory also. As impressive was the level of skill and precision of the machinists (or tool and die guys) that worked in the tool shop keeping the broach cutters sharp and tuned.

For those of us not familiar with broaching, this is pretty good:
http://m.youtube.com/watch?v=7n1r5XfVkyk
This too:

http://m.youtube.com/watch?v=rjckF0-VeGI

 

[Doug M.]

Looking at the stress issue with the aluminum-scandium alloys makes me think that maybe the issues with barrel tightening and frame cracking is related to the stress tolerance of the alloy used. I think that's a serious problem, as proper barrel mounting is not an option.

I will also note, however, that most shooters do not put a lot of rounds downrange. The higher volume shooting of the last decade or so was much less common 50 years ago, and I have seen the statistic claiming that most folks put 600 rounds downrange in a gun's lifetime. If correct, then a 2000 round service life in a gun that one carries a lot and shoots little (like a snubby in its best role, as a BUG) is no big deal most of the time.

I have had the same experience with exercise equipment. Most made for home use becomes a coat rack soon after purchase, so if you are a big ape who beats hell out of the gear as I sometimes do, the typical entry level stuff will die a quick death.

 

[M29since14]

This is drifting a bit but on the heels of Doug M.'s comments, probably most (or at least a lot) of us can remember Elmer Keith writing about his skepticism of the Airweight Chief, which he subsequently debunked by means of his own field testing - with his own handloads, no less!

At that time he wrote that the big wigs at S&W stated the intended service life of the gun was 2500 rounds, IIRC. He satisfied himself that the provided test gun (as in one test gun) held up nicely for that. Nowadays, the way some people write about "training" you would imagine they go through 2500 rounds in a year or less.

In EK's opinion, that kind of service life for the airweight gun seemed a reasonable trade off for the convenience, and he recommended practicing with your steel gun and carrying the airweight. I know a few of us who did just that.

 

[jaymoore]

From doing work on an N1K2 Shiden Kai I found that the first use of the 7000 series aluminum alloys was in Japan. Used in the main spar webbing of the Zero, and later in the Shiden kai, etc. SDCH was their marking on the parts so used. So, in this case, it was the Americans who followed in the Japanese footsteps...OT, but good ideas are where you find them.

Back on topic, I tend to not keep aluminum framed pistols or revolvers very long! Not if they get shot or handled very much. Once the anodizing is worn through I reckon that's enough. That layer of hard oxide is what prevents most of the wear. Never mind the lack of a lower endurance limit on "fatigue" life.

Practically speaking, it's why that heavy hunk of 940 rides around with me rather than one of the airweights.

Your friend is a rare engineer that not only knows his stuff, but can communicate effectively, Dave T. I can barely string a couple of sentences together...I'd rather do the math or fabricate something. He!!, most MEs can barely spell, and that's the ones with real aerospace jobs!

 

[Bullet Bob]

What is the prize for best thread of 2013?

 

[Green Frog]

DaveT, if you came back aboard when this thread was raised from obscurity, could you be so kind as to ask your friend about the MIM technology that has been subject to so much heat and so little light on this and other forums? I for one would love to hear what he has to say, as I am sure we could "take it to the bank!"

Regards,
Froggie

 

[Tom K]

What is the prize for best thread of 2013?

You mean for 2009?

 

[Dave T]

Green Frog,

I just found out this old thread was resurrected (who'd a thunk it - lol). He and I have talked about MIM a number of times. I'm not going to try to explain what I've heard him say as some of these conversations go back as much as 10 years. I know he's away from home solving some engineering problem for his company/industry (it's what he does for them) right now. I"ll get in touch when he comes back and see what he can send me about MIM.

Dave

 

[Llando88]

Dang! This is one interesting thread. Allow me to continue to sit here and listen.

 

[Pitdog02]

Considering that it was commented that 416 stainless is anemic compared to the 41 series low carbon steel, I doubt there will be a politically correct non offensive way to describe the MIM situation. I had a good look at the MIM parts in my 2 J frame scandium 357s during a action/trigger job. I will say you don't have to be an engineer to realize what you were looking at was not quality hand fitted parts or process.

 

[SweetMK]

It is tough to contribute your opinion in a thread such as this without stepping on someones toes.

Materials selection is a difficult process, in almost all cases more than properties MUST be considered.

Yea, we hate to hear it, but cost, and appearance DO come into play.

Then reliability of proper manufacturing processes come into play.

Pick the best material, require a SPECIFIC heat treat, watch manufacturing find a lower cost way of doing that heat treat, the material choice becomes a failure. BTDT -

My BTDT actually involved 17-4 PH, manufacturing "thought" a shorter heat treat, with all the parts stacked in a pile, was adequate.

What did they think, we were killing the bacteria on the surface????

Fool proof material selection typically is the driving force for materials engineers these days, when designing low cost assemblies.

Million dollar jet engines get more careful processes.

MIM is a fact of life to keeping a $600 (wholesale) revolver on the market, along with rubber grips.

IMHO

 

[DWalt]

Unfortunately, what used to be steel is now plastic or MIM. In today's economics, you can't produce a gun in the USA by using the same methods used in 1950. No one could afford them.

 

[rjb1]

As an engineering professor I agree that this is really excellent information. It's to some degree a synopsis of two upper-level mechanical engineering courses: "Design of Machine Elements" and "Manufacturing Processes".
What he said is what you hope that the students pick up to the extent possible.
The only slight addition is historical, not technical, and that is that the 8620 chromium, molybdenum, nickel alloy actually pre-dates M-14's and was used in M1 Garands back into the 1930's.
(Also, current-generation ME's are really good at both speaking and writing.)

 

[SweetMK]

(Also, current-generation ME's are really good at both speaking and writing.)

Is this like getting your car fixed?

Your ME can be good at two;

Speaking
Designing
Writing

Pick two!!



I went to college to be an engineer, now I are one.