An Engineer's take on S&W.

[BigBill]

I build a cnc lathe to machine the m1Abrams main engine rotor which is titanium. The machine they purchased from Japan couldn't handle cutting this metal. The tooling to cut the rotor was $250k in the early 80's. The federal inspector also witnessed a horse power cut we did on all the machines for the oil industry. We took a one inch wide cutter and drove it into a steel billet till we got the amperage rating and horse power from the motor running the machine. The curly q's came off the billet sounded like machine gun rounds hitting the guards. The inspector seen this and went wild about what a Bullard machine could do. These machines could hog yet hold tolerances to the millionths.

Stelite is used in making exhaust valves in engines. It can take the heat yet also take the gas we use today. We removed the materials that cushion the valves when they hit the seats like the lead. With these engines running hotter today to get the emissions better probably both valves are stellite now. My valve grinder needed special grinding wheels for stelite valves. The standard grit wheels couldn't touch this harder steel.

 

[DWalt]

I doubt there is a S&W MIM part that is not sintered.

MIM involves heating after forming from powdered metal, but the actual MIM process is substantially different from sintering.

 

[JDBoardman]

Broaching is a really cool process. We use it extensively in turbojet and turbofan engine manufacture. Each turbine, compressor and fan disk may have as many as 72 broached slots around the perimeter to hold the blades. Since the major loads on the blades are in a circumferential direction, using fasteners to hold the blades won't work, and since the blades are removable for economic overhaul of the engines, some method of positive location and retention is necessary. Hence, a Christmas tree-shaped broached slot for each blade, and a matching fir tree-shaped root on the blade. The complexity of the slots mean that broaching is the only feasible fabrication method.

The blades themselves are investment cast, so complex shapes are not too difficult to make. Again, the stress loads are axial along the blade, and are also complicated by high temperature creep, heat-accelerated corrosion, erosion, etc. Special nickel superalloys are used, since, as your friend indicates, a collection of various properties need to be considered to achieve the optimum results. In addition, specialized cooling processes are used in the casting process to achieve axially oriented solidification, or, ultimately, single-crystal solidification. These parts are not typical investment castings, and the properties desired are achieved by both alloy composition and cooling/solidification processes. (and, as an 'oh by the way... S&W Forgings make certain specialized small parts for us, so they are still in the forging business).

(edit for Mbliss57 - did Wyman shut down the 50K ton press they had in Houston? We used (2000-2001) to make Offshore Platform Risers [40' long, 36" diameter, 4" wall] from titanium mults and CFM56-3, -5 and -7 fan disks from Ti 6-4)

 

[mbliss57]

Good article explaining MIM

I posted this in an edit but many like me don't often reread old posts.
The MIN process explained. There are even Pics!!

http://www.pim-international.com/aboutpim/binders

Mike

 

[mbliss57]

Broaching is a really cool process. We use it extensively in turbojet and turbofan engine manufacture. Each turbine.....
(edit for Mbliss57 - did Wyman shut down the 50K ton press they had in Houston? We used (2000-2001) to make Offshore Platform Risers [40' long, 36" diameter, 4" wall] from titanium mults and CFM56-3, -5 and -7 fan disks from Ti 6-4)

JD.. I was not aware WG had a 50K ton forge press in Houston. I was told (by colleagues at WG) they only had the one at WG in Worcester, MA and 1 at Alcoa in Cleveland. (I have seen the one in Cleveland) I will research it. If you used it.. it must be there. The 2 up North were made under USAF contract right after the WWII when Americans found a destroyed 50K ton press in post nazi Germany. Both have been rebuilt since.
Do you still work for WG?

Edit: I was wrong about the MA location. The 50K ton press at Wyman Gordan is in N Grafton MA not Worcester. The one in Houston is a 35K ton press.
Wyman Gordon Forging Companies | Wyman Gordon Grafton Forging Operations

I wonder what the largest press S&W uses on it revolvers?

Mike

 

[Doug M.]

I'm glad you broached the subject.

*
Hahaha. I see what you did there.

 

[Abwehr]

Being an engineer myself, I have followed this thread closely and agree with most areas of firearms manufacture from the correct steel, aluminum, and various alloys. Then which is best forgings, casting, MIM, etc.

But, what about some of the latest aluminum alloy with Lithium. I know Li-Al is know the world over, but there are some "recipies" of Al-Li that is proprietory and have the ability to reach 50-60 kps. The material being lighter and stronger than other aluminum alloys. The only problem with the strength is that it is in one direction. What are the thoughts from other with Li-Al in firearms?

 

[jaymoore]

Broaching is a really cool process. We use it extensively in turbojet and turbofan engine manufacture. Each turbine, compressor and fan disk may have as many as 72 broached slots around the perimeter to hold the blades. Since the major loads on the blades are in a circumferential direction, using fasteners to hold the blades won't work, and since the blades are removable for economic overhaul of the engines, some method of positive location and retention is necessary. Hence, a Christmas tree-shaped broached slot for each blade, and a matching fir tree-shaped root on the blade. The complexity of the slots mean that broaching is the only feasible fabrication method.

Couldn't find a good christmas tree photo right quick, but these slots are likely broached as well. (Photo taken during initial set up of a spline check for re-establishing the indiron mark.)

Bringing things back a ways, we talked to some of the old Curtiss engineers and they stated that the main reason that they forged many parts was just to increase production. It was quicker to produce near net shape parts using this process than any other available at the time and still have reasonably light weight components. Nuances of refined grain structure, etc. were of secondary concern, and if other methods had been availablr, they would have used them! Very un-nostalgic fellows. No reason to assume S&W was any different. They just had no pressing reason to modernize for quite a spell.

A NOS P40 fuselage lower longeron attach forging and my tracer mill billet "in process" new production parts which are currently flying:

 

[Black_Talon]

Didn't we have these MIM pro/con discussions ad-nauseam a few years back? Does this need to be rehashed?

 

[SweetMK]

Didn't we have these MIM pro/con discussions ad-nauseam a few years back? Does this need to be rehashed?

It is either re-hash, or discuss retirement benefits!!

 

[mbliss57]

Didn't we have these MIM pro/con discussions ad-nauseam a few years back? Does this need to be rehashed?

This is not IMO a "what is wrong with MIM" as much as the differences and process of each. The MIM vs Forged debate is dumb. Forged parts are stronger. MIM parts are cheaper. More money gets a better/ stronger guns in every inch of the revolver/semi auto. It doesn't get a cheaper one. So there is no debate on which is better. Only on if we can afford all guns made with only forged parts or if all forged parts have the need to be forged.

Edit: There are many new members that probably would like to know what this discussion means to them as gun owners.

 

[jaymoore]

Edit: There are many new members that probably would like to know what this discussion means to them as gun owners.

Practically speaking? Little to nothing! Except that MIM parts are more likely to be drop in replacements should the need arise. It seems that the the newer bolts are finding favor with the IPSC and ICORE shooters over the old style. (Ref., for instance, the Brian Enos revolver forum for more detailed discussion for what works under speed and with high round counts.)

Probably the most signifigant improvement S&W has made over the years is the adoption of more heat treated parts. Frames, yes, but more so the smaller components. However, it's an invisible change so doesn't attract much attention.

 

[Doug M.]

...
But, what about some of the latest aluminum alloy with Lithium. I know Li-Al is know the world over, but there are some "recipies" of Al-Li that is proprietory and have the ability to reach 50-60 kps. The material being lighter and stronger than other aluminum alloys. The only problem with the strength is that it is in one direction. What are the thoughts from other with Li-Al in firearms?

*
Lithium/aluminum alloy in firearms? I am not familiar with such. Can you tell me what makers are using this, and in what firearms? I am utterly ignorant of this, and curious.

 

[Abwehr]

DougM,

Currently, there are none of the AL-LI alloys being used on firarms, but with the low weight factor, and strength it has (in certain directions according how it is manufactured) of low carbon steel, it may have a use in firearms. I know it is used in the NASA program, and major aircraft manufacturers. I was not sure if anyone had presented any Papers on the use in firearms. Due to the stress factors on firearms, it could be machined to match these stresses. I know it could be used in the AR receivers and be much stronger than the what is currently being used. But is any additional strength needed on the AR.

 

[Doug M.]

Thanks. I wonder if it would be a good choice for certain components, depending on how it resists stresses of different types.

 

[BigBill]

What does MIM mean? Is it casted parts vs machined parts? They do harden both parts right?

If there on the ball with there CAD Systems they can run the stress part of the program and reduce costs in some areas were there design is over kill.

 

[mbliss57]

MIM= Metal Injection molding see post #83 for a link to process diagram.
Neither cast nor forged. Not as strong as either.. I would be surprised if they did not run 2D or 3D stress modeling to determine stressed areas and design to exceed those stresses.

 

[BillyMagg]

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.)

Quite right, this is an outstanding thread on fine steel and aluminum, but of course we will never convince the true believers in investment casting, but hey, somebody's gotta buy those guns, and that just means more Smith and Wesson's for the rest of us. LOL

There are several AEs and MEs that post on the Sino Defense forum, they write and present quite well, after doing my own welder and bailing wire engineering/fabrication, I came to the conclusion that the engineers were usually right, the sideline commentaries,,,,, not so much!

 

[jaymoore]

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.)

I just ran across this old photo whilst linking a linseed oil cleaner photo to another thread. Don't remember why it was taken, except it's got some great reference material. (Newest is probably 1980s, but some things don't get better in newer editions. Like Timoshenko's book: the first edition was the best.)

Spotts' book ain't bad. Which is why it's still about the house, I guess.

 

[mjdupuis]

Very interesting information. If I read this correctly, stainless steel is not as good as normal blued steel in revolvers.
Would this apply to rifles as well; would a stainless action and barrel in a rifle be a step down from the regular steel as far as durability and long term life (beside the all-weather properties of stainless)?

 

[SweetMK]

Very interesting information. If I read this correctly, stainless steel is not as good as normal blued steel in revolvers.
Would this apply to rifles as well; would a stainless action and barrel in a rifle be a step down from the regular steel as far as durability and long term life (beside the all-weather properties of stainless)?

Stainless is a "tradeoff" material, you trade one trait for another.

In this case, you trade corrosion resistance for strength.

Strength is not the main issue with stainless.

Galling is the real issue;

Galling - Wikipedia, the free encyclopedia

IIRC, AMT had major issues with galling, it was kinda the downfall of the company.
(Did AMT make anything that was not stainless?? )

I love stainless, I doubt I will buy any gun that is not stainless, unless it is at gift price.

Since the original S&W's have some margin in the strength of the blued guns, a little of the margin is used to allow a nice stainless to be made to the same dimensions.

THEN, we could discuss how much more difficult stainless is to machine,,,,,,,,,,,

 

[gunbob1911]

Very interesting read. I am not an Engineer and most of this stuff printed here is 'way over my head ". I am a retired LE 30 years and love wheel guns, S&W, Colt, Ruger in that order. I always kinda looked down on a Ruger because one of the reasons is it a "cheap" investment cast frame you see. A few years ago I took a Revolver tuning class at an accredited Gunsmithing school. Our instructor was a retired Captain and Gunsmith for the Colorado State Patrol with 40 years plus experience with wheel guns used in LE and related this story to our class. Having access to lots of guns from the property room that were confiscated for various reasons they decided to do a little"experiment ". Using bullseye powder they filled the case to the top of a.357 magnum, and seated a 158 grain bullet. S&W, Colt and Ruger wheelguns where put through a torture test to see which guns if any could survive it. The guns where place in a fixture and fired by using a string on the trigger from a safe distance. Too make a long story short the S&W and Colt which are "forgings" where quickly destroyed while the Ruger was not. They could not compress enough powder in the case to blow up the Ruger. They also backed over it with a 3/4 ton pickup and the gun still functioned . To me the 'proof is in the pudding". I have not ever owned a Ruger wheel gun but every once in a while at the LGS I will pick one up and check it out thinking you know if I ever go to Alaska I think I would bring one of these because it will probably survive being dropped a long way or shot with mud in the barrel or even accidentally being run over by a truck. I have witnessed this myself when the gun is placed on the hood or roof of the vehicle then only to be run over by the Driver who "forgot. "Stuff happens " and I would trust that Ruger to be there for me if one is depending on it for self defense against a big critter that could have you for lunch. Thanks, one mans opinion.

 

[Pondoro]

One thing that has not been discussed here. I am an engineer, so I respect them, but they cannot predict the future. Smith made guns for decades using forged parts. These parts wear out, but the wear out rates are slow and predictable, because we have hindsight. MIM and polymer parts are not as predictable, simply because we do not have millions of guns built over five or six decades to help us predict.

Aviation is adopting MIM and printed parts and polymer parts right now to save weight (which saves fuel). But safety critical parts are tracked and all manufacturers run test "endurance" engines to show what these parts will look like after thousands of flights. If you fly on a plane powered by the new "XYZ" engine and your plane has an engine with 2,000 flights on it then you know that "papa" engine manufacturer got more than 2,000 flights on a ground test engine. If a safety critical part fails on a ground test engine or even shows unexpected distress in an overhaul we go after every part in the fleet and replace them. No one is doing this with guns that I know of. So I worry what is the life expectancy of a polymer framed gun? If the frame cracks after 25 years and I am an LEO I will get a new one and be glad the old one (which I carried every day) was light. But if the frame cracks and I am a collector I may not be able to replace that gun. We could say the same about MIM parts and printed parts - they may have failure modes that we simply do not expect. So for collecting and long-term shooting I think a bias towards forged is somewhat reasonable.

It is never obvious how much strength is enough. You want a factor of safety but how much do you need? It is difficult to predict what the users will do. Investment cast guns have been made by Ruger for decades, and I do not hear tales of Rugers blowing up, so if they give up some strength to forgings they are compensating somewhere. Rugers do often seem a bit larger than Smiths, in the thinnest areas.

 

[Pondoro]

I just ran across this old photo whilst linking a linseed oil cleaner photo to another thread. Don't remember why it was taken, except it's got some great reference material. (Newest is probably 1980s, but some things don't get better in newer editions. Like Timoshenko's book: the first edition was the best.)

Spotts' book ain't bad. Which is why it's still about the house, I guess.

Is the 4th from the bottom Shigley? I have one that cost $33, I have my father's copy which cost $7.95, and I had a young engineer who worked for me whose copy cost $120.

 

[jaymoore]

Is the 4th from the bottom Shigley? I have one that cost $33, I have my father's copy which cost $7.95, and I had a young engineer who worked for me whose copy cost $120.

Yes. It's probably got the price sticker inside, but I'm not within 30 miles of it right now. Probably closer to the US$33 mark, but it's hard to remember. I tried to buy books used whilst in "trade school" and the habit has remained!

As far as unexpected failure modes go, I'd include aluminum alloys in the list. Might take some photos of aluminum that now looks like splintered wood! Even the aluminum that's not "exploded" tends to age harden.

 

[rjb1]

That is an edition of Shigley, but can't say which it is. A GREAT series of machine design texts. I still have the edition that I used as an undergrad and I have used it so much since that it is falling apart.
Anyone here, engineer or not, who wants to learn a good bit about the subjects being discussed in this thread would be well-advised to pick up one or more of the various editions of Shigley.
His books had such a good reputation that new editions with his name on them were being published a decade after he died.

Aluminum alloys don't have an "endurance limit", as do steels, so they will fail at some point due to fatigue if you keep on stressing them. (See Shigley, 2nd Ed. Page 160, "Fatigue Strength and Endurance Limit".)
The key is to design using a high enough number of fatigue cycles to allow for a "sufficient" lifespan for the item in question. This is a design decision, and is not based on an inherent property of the material, as you could use for steel.

 

[Jim Watson]

"But if the frame cracks and I am a collector I may not be able to replace that gun."

I read an automobile collector to say something of the sort.

He pointed to his daily driver, a new Lincoln and said "This car is mostly sheet metal stampings and plastic. When the warehouse runs out of spare parts, it is done for." Indicating his elderly Packard, he said "But as long as I can hire a machinist, a carpenter, and a seamstress, I can keep this one looking and running like new indefinitely."

 

[Oyeboteb]

"But if the frame cracks and I am a collector I may not be able to replace that gun."

I read an automobile collector to say something of the sort.

He pointed to his daily driver, a new Lincoln and said "This car is mostly sheet metal stampings and plastic. When the warehouse runs out of spare parts, it is done for." Indicating his elderly Packard, he said "But as long as I can hire a machinist, a carpenter, and a seamstress, I can keep this one looking and running like new indefinitely."

Tell him to get a 'teens or 'twenties Dodge ( with the 'Budd' All-Steel Body ).

He can get on fine then, indefinitely, with out the Carpenter.

And he is welcome to 'Ask the Man who owns one!"

Lol...

I had a '26 Dodge Roadster for a short time, some years ago. Absolutely marvelous workmanship and design and fit through out. Stamped Steel Disc Wheels, no Wood anywhere in or on it.

It had sat outdoors in the weather here in Las Vegas for almost 60 years, and, the Doors still functioned perfectly, closed 'Like a Bank Vault', same with the Trunk and Hood and so on, none of the woes which thin Sheetmetal nailed on to Wood Frames have.

I accept that modern cars have 'advanced or sophisticated engineering'.

The most boring, totally uninspiring, and anticlimactic 'engineering' I could ever hope to have to stomach.

None of which will endure, and none of which will inspire anyone, 60 or 80 or 100 years from now.

A Hundred years from now? 200 years from now? 300 years from now? There will be more Ford Model T Automobiles, up and running, Get-in-and-go, than viable/running 'survivors' of the 33 year total of all makes and models made from 1980 to the present.


Yes, present day cars work well, in their way, as what they ( actually ) are, an expensive 'Bic Razor' which one uses and throws away...and, they are a total bore, from every view inside and out, underneath, hood open, hood closed, every detail inside and out, on any road, any weather, any time, day or night, a total boring ridiculously over-complicated throw away item, devoid of any memorable or substantial character, genius, or individuality. All 'value engineering' and slick marketing and a nightmare - or just depressing - to Work on.

Ohhhhh, golly...so it goes...

Nothing against Packards ( I do love them afterall! ), but, it this were 1926 and I were intending to drive from LA to New York, and back, I'd have bought a new or used mid '20s Dodge Roadster..!

 

[mbliss57]

I made that analogy... And every analogy breaks down at some point.
It's wasn't the best analogy buy all I could come up with at the time.

OVEBOTEB....you kind of make my original point though. New cars are not collectible but very function even over functional. Classic cars like the classic guns of the forged only era are collectible. The new ones are quite functional, lightweight etc. but will never have that collectible appeal of the forged all steel guns.

 

[DWalt]

When we get hit by the EMP, the only things left running on the highway will be bicycles and really old cars. The best car I ever had was a 1952 Chevy - but it eventually died of body rust after over 300,000 miles.