I read where a well known gun Smith refuses to work on certain S&W revolvers because of the min cast frames? I think it's a "6" in the model number. (K frame)

Does the new n frame have a casted frame too?

MIM = metal injection molding, currently used to produce revolver hammers and triggers (and I read somewhere here J frame barrels also).

All steel S & W revolver frames are forged, and I think the alloy ones too.

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Alan
SWCA LM 2023, SWHF 220

Metal Injection Molding. It is a method that adopts certain techniques from the plastic and composite injection world and adapts them to metal structures. Starts with powdered metal mixed with a resin, the part is injected in a mold then heated to a very high temp in something akin to an autoclave. The resin "evaporates" and the metals shrink to a very precise size that can be further machined where needed. (This is strictly the $.01 description of the process). The process comes from the aerospace industry where tolerances are far tighter than anyone in the firearms industry ever thought about using.

MIM is not popular with many because it sort of sounds like injection molding, not anywhere near as classy as forging and machining.

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"Sacramento" Bruce Conklin

A leading number "6" in a S&W model number usually indicates stainless steel. For example: the M629 is the stainless version of the blue N-frame M29. The M686 is a stainless version of a L-frame M586. The M638 is the stainless version of the J-frame M38. The M64 is a stainless version of the famous K-frame M10. The M610 is a stainless 10mm N-frame (and is not based on the M10 -- the system isn't perfect).

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~ S&W aficionado in training ~

Excellent explaination and Assessment. Mim parts are easier to manufacture at extreme tolerances but some people still refuse to accept it.

My question is: How do MIM frames compare in strength to forged frames???

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Not in Kansas anymore, Toto.

IMHO, as a retired pistolsmith, the mim parts are as good functionally as forged/milled parts and sometimes are better. The hardness can also be greater where necessary. Other than 'classic' looks, IMHO, the handguns with mim parts are as good as those without and sometimes are better. But, now ask me about 'plastic' parts. I recently acquired a S&W M 351PD. Of course I had to look inside it. Much to my dismay the spring cup on the mainspring guide is of plastic. :-( ! I found a steel one in my parts drawer and changed it out. Ugh! A plastic part with a hammer spring bearing against it. S&W, what were you thinking? ......... Big Cholla

Heavens knows I am no S&W expert and I do not try to keep up with the latest coming out of Springfield, but IMHO there are no frames for S&W handguns being made from MIMs. Undoubtedly S&W research dept. has already been experimenting with that concept but none has made the market. Other manufacturers might be using the MIM process for their 'frames'. When you see the reference 'MIM frame' in conjunction with S&W, I'm sure that just means a standard forged and milled steel frame that has been fitted with some MIM internal parts. ....... Big Cholla

Since S&W doesn’t use MIM frames and I’m not aware of anyone who does, this is a question w/o an answer. Don

For the OP with over 5000 posts, I’d have thought you’d be more conversant with this issue which has been debated and discussed to death.

MIM parts are strong, precise and economical. They’re here to say despite the dislike of the old is better school. Don

[QUOTE But, now ask me about 'plastic' parts. I recently acquired a S&W M 351PD. Of course I had to look inside it. Much to my dismay the spring cup on the mainspring guide is of plastic. :-( ! I found a steel one in my parts drawer and changed it out. Ugh! A plastic part with a hammer spring bearing against it. S&W, what were you thinking? ......... Big Cholla[/QUOTE]

Did the same on my 43C for the same reason.

If he thinks they have MIM frames, he may be well known but he is not at all knowledgeable...

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Pisgah

Ok here's the post about the min castings.

http://www.clementscustomguns.com/sm...revolvers.html

If the plastic cup is changed out for a metal one on a revolver with a lifetime warranty has doing so now voided the warranty?

I'm sorry I don't know everything. The one person who did was crucified. If I don't fully understand something I ask. There are many different processes in castings.

Did you mean this to be for a different thread?

It belongs in this thread; KC was saying it's unlikely a MIM frame would have a "6" designation -- per the original post -- because "6" denotes stainless steel.

If you're going to be a scold, you might want to make sure you've read and understood the OP first -- he asked if S&W was making MIM frames; he did not rehash the MIM debate.

Thanks for the clarification.

Read the OP. I took it to mean he was asking if the number "6" had any significance in regards to the frame's metallurgy. If you study S&W model numbers you learn the number six does have a very specific meaning, which I attempted to explain.

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~ S&W aficionado in training ~

That's in regards to MIM parts used in the lockwork of current S&Ws; it has nothing to do with the frames.

Mr. Clements (who has an exceptional reputation as a revolversmith, though he's known mostly for is work on single actions and Rugers) is saying he finds that MIM internals do not lend themselves to action work the way forged internal do, and so he declines to perform action work on MIM parts. He's not the only reputable gunsmith to arrive at this conclusion.

Hopefully this answers your question, Big Bill.

I guess the OP's question was unclear to me because S&W frames are not "MIM" or "Cast". So, the "6" numeral in the model number has nothing to do with being "MIM" or "cast" frames. If I'm wrong I not surprised. Please educate me!

Sorry Clements states the back of the trigger has cavities casted in it(mim)
My mistake I thought he was talking about the frame were the back of the trigger has cavities casted into it.

I was told here all the S&W n frames are forged steel.

Historically, S&W has been very generous to their customers in the "Lifetime Warranty" interpretation. There is always that ominous 'But' hanging just off the shoulder of the first S&W employee to look at a returned handgun. For a whole myriad of reasons that employee could say, "I just don't want to log this handgun in for repair and here is a reason to say NO." Or, in the usual case the employee ignores the obvious part change as being inconsequential and we the customer gets whatever fixed on the S&W Lifetime Warranty hook. So, that is why I dropped that little piece of plastic back into the factory box for my handgun. It would be where I could find it if I ever needed to send back that handgun on a warranty issue. This whole question is moot for me. I will never return a S&W on a warranty claim except for a broken frame. I know they break on occasion, but I have never had one break. Certain air weight revolvers are known to break at the barrel shank threading.

I did see a broken frame on a M 3913 that an acquaintance had used to shoot IDPA for about 4 years. He thought he had shot it a minimum of 50k times. The frame cracked thru the slide stop port. S&W gave him a new frame with the same serial number and did a complete rebuild on the slide including a new barrel. He had bought the 3913 new. I was so impressed with the performance of both the pistol and the customer service I purchased my first M 3913. I have carried it for my CCW ever since.

But I digress from the question; Answer, "They could, but probably wouldn't". ................ Big Cholla

I did an installation at a shop that specializes in this process that builds high pressure valves used in turbine engines. Pretty amazing to watch and see the results. Tolerances and quality are more than good enough for my 629 and your pistols.

I'm gonna jump in with a comparison here. Ruger uses investment cast frames on their DA revolvers as a way to keep machining costs down. To my knowledge their frame strength has never been an issue for that company. IF S&W ever did produce a mim frame I am confident that three things would have to happen, before they released them to the public. First, a redesign of the frame. They would likely need to be made slightly heavier. Second some serious testing to failure and tweaking the design to protect the S&W quality reputation. Third, and this is where the idea would probably die, a massive PR push trying to convince the gun buying public that these are somehow better than any previous design.

Just my 2 cents

I own brand new S&W N Frame Revolvers and older K & N Frame Revolvers also. I think the S&W warranty is awesome and it's there if we need it. I own a 1911 that has an investment casted frame. From another gun manufacturer. We put 500rds through it of non stop action. The three of us hammered it. She passes the functioning and reliability test for ccw carry plus the frame held up well after all its 4140 casted steel.
I lube my guns with moly. This way all the triggers feel equal when switching to shooting different guns that's a big plus when every trigger feels the same.

Much of the bad rep from MIM pRts was do to early production Kimbers who outsourced inferior MIM parts .Kimber back in the late 90's bought a premier Aero Space MIM factory. ( name escapes me at the moment ) and there have been no problems since.Both cast and MIM breakage are to a equal today.

I thought that, "MIM", stood for Mashed Into Metal. Guess I don't know as much as I lead myself to believe!
peace,
gordon

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better have that checked

That's the process they use to install the lock; sort of like a crush fit barrel.

I'm not a metallurgist but at a gut level it would seem that a chunk of metal that was a homogeneous chunk o' stuff with a continuous crystal lattice would be better than a bunch of teeny metal bits that are essentially welded together. Just sayin' (as the young 'uns say).

It may be easier to manufacture and may be "almost as good."

As for "aerospace" applications, meh. Stuff in the aviation world is subjected to regular inspections and replaced if anything looks iffy. How often do we magnaflux the hammers in our guns.

Damascus steel is just a bunch of piece of steel headed and mashed together and it ruled the steel world for years. (not cheap Damascus barrels which were actually silver soldered) The very best steel you can buy is formed by spraying the molten alloy in an inert atmosphere and then the tiny balls are pressed together to weld under high heat. The very best knifes are made with this type steel and they are superior in every way to regular forged steels. Oh, ya so are jet turbine blades which take extreme pressures and get a lot more hours on them than any of our revolvers ever will.

Just because something is different or new technology doesn't mean its inferior. Hardly.

PS. I have a 1917 with a pinned barrel. I can roll the barrel about 5 degrees in either direction with the pin in it. Barrels have always been crush fit. Pin was just an extra.

Hardly ruled the steel world. Trains weren't made of damascus, neither was armour. It ruled the sword making world.

You can have your MIM. I'll take my metal as Hephaestus intended it to be made.

If MIM is good enough for turbine blades in jet engines, it should be plenty strong for most firearms.

That and the parts themselves are butt-ugly compared to forged, case-hardened lock work.

With all due respect to Mr. Clements, the smiths I've talked to prefer MIM parts for their consistency. They say tolerances on forged parts were so loose they never knew how much work an action job was going to take till they got inside the individual gun.

MIM parts are better than forged. Stronger, held to tighter tolerances. Parts in aerospace applications are subjected to stresses no one in the firearms industry would even dream about.

Many aerospace parts are replaced on a time-based schedule. It has failed, it does not show any wear, but the standards developed in the 50's tell us it has to be tossed. We used to look in disbelief at what we were tossing, shrug our shoulders, and toss.

Just a note, Smith & Wesson handcuff keys are MIM products. There is a lot of force applied against that little tab quite often.

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"Sacramento" Bruce Conklin

Exactly and MIM parts are used because they are cheaper.

NOT TO HI-JACK THIS THREAD, BUT............... I see nothing wrong with this or any other legitimate & honest question no matter if it has been discussed before or not. There are many members here (that even though they have been long time members) have not been interested in a subject or topic prior to asking a specific question at a certain time - even though there may or may not be plenty of posts prior. I post and ask topics and questions that I have not done extensive research on and that is what this Forum is about - helping, sharing and discussing. Some one should not be crucified for asking a question that he did not do an extensive search or had given long thought about before posting. If someone has discussed (posted) the answer too many times that he is frustrated - just ignore the post and let another member respond. No need for excessive bitterness!

HAPPY THANKSGIVING EVERYBODY!
Chief38

The early Kimber internal components were eventually outsourced to Chip McCormick. I have one of the earlier Kimber Classic Custom 1911's. It's a real tack driver, that didn't break the bank $625 OTD in 1997 or 98. My BIL has lusted after it, ever since he first shot it in 06. He has since bought two Kimbers.

I think the MIM process was initially confused with "Cintered Metal" where metal filings were heated and pounded into a part mold. The metal tended to have voids, that made the parts fragile and prone to corrosion. I understand that Colt used this inferior manufacturing process in the mid 70's for their revolvers.

Made a call to S&W about that very question . Your post and his answer are the same.

I believe the mim technology started with the space program and have been proven to be very strong with improved accuracy in the parts manufacture.

All the manufacturers that I know of, that make cast frames, use a process called "investment casting" to make their frames. It's a process that uses molten liquid metal. It is very different from MIM.

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~ S&W aficionado in training ~

Probably because MIM stuff is sintered after it is formed.