MIM parts - What's the real story?

[Emerson]

What is the real deal with MIM parts.

Are MIM parts more likely to fail?
Do MIM parts result in worse trigger pulls?
Do MIM parts cause the chickens to quit laying and the cows to dry up?

I know a lot of guys who cuss em and say they wouldn't own a gun with MIM parts......yada yada.

Has anyone EVER had a problem with them?

 

[18DAI]

I don't care for MIM parts, they are a cost cutting method IMO. They are not a deal breaker, for me, that some other "innovations" are.

I've had two incidents with broken MIM parts. One, a thumb safety on a Kimber Stainless Target II, snapped. The other was a mag catch on my S&W 4516-3. The catch snapped where it enters the mag well, and would not secure the mag in the well.

Are MIM parts more likely to fail? Depends on how well they are made.

Yes, for me, in the S&W revolvers I've handled, the MIM guns trigger pulls were gritty. I did not purchase said revolvers.

No MIM does not cause chickens to quit laying or cows to dry up. MIM simply increases the profit margin of manufacturers who are putting out cheapened crap with famous logos laser etched on them. Regards 18DAI.

Regards 18DAI.

 

[Aussie44]

No MIM does not cause chickens to quit laying or cows to dry up. MIM simply increases the profit margin of manufacturers who are putting out cheapened crap with famous logos laser etched on them. Regards 18DAI.
Regards 18DAI.

Well said,Forged not Cast.If I want a cast revolver I'll go buy a Ruger (Not).

Ken

 

[gizamo]

Well said,Forged not Cast.If I want a cast revolver I'll go buy a Ruger (Not).

Ken

Come on Ken,,,,,
We all know you must be a closet Ruger guy!!!
Don't you ever feel the need for investment cast parts...

And for the record...things like the hammers on the older guns were not forged...it's a misnomer and has always been.


As for MIM I actually broke down and now own one....I never intend to shoot it, but I got's one



giz

 

[Aussie44]

Hey Giz...
I purchased a Redhawk .44 Mag over 20 years ago to use with my recently purchased 310 gr JDJ bullet mould so I could load it real hot.(I think it was 1986).Was that gun rough as guts(pourus internally) and the trigger...No where near a S&W no matter what I did.So I ended up selling it.I'm a one eyed S&W revolver man.And for Auto's a Colt 1911.I know you've got a few Rugers and they do look nice ,I'm not knocking them,I just prefer Forged Smiths.

Ken

 

[Snapping Twig]

MIM is good enough to do the job.

I sold the only pistol I had that used it, just not right for me.

I've seen it fail, looked like a pot metal inside at the break.

Get it and don't worry about it, but there are those like myself that won't.

 

[BruceM]

This has been discussed and been debated so many times that there should be a "sticky" thread for it. Personally, I have trouble accepting the concept of the MIM parts along with that of the flush toilet.

Seriously speaking, MIM parts, when properly made are superior to conventionally manufactured steel parts for most applications in which Smith uses them. That said, they absolutely stink when substituted for the color case hardened triggers and hammers. Cosmetics matter whether Smith & Wesson has figured this out or not. Then again, I guess an argument can be made that S&W has thrown cosmetics (and revolver customers) under the bus in exchange for cost benefits.

Just my opinion which, when added to a buck & a half, will get you a cup of coffee.



Bruce

P.S. After MIM manufacturing, lets discuss unibody automobile construction.

 

[glypnir]

Smith and Wesson is trying to stay in business. Who is the other American manufacturer who makes revolvers the way Smith and Wesson used to? They're outselling Smith, right?

Or are they out of the business? Are they perhaps Colt?

And who hasn't taken similar "cost cutting" measures on their rifles? Was it perhaps Winchester?

The defense rests, your honor.

Now I can understand why some of you collectors of old Smiths want them to go out of business - you are jealous of those Colt collectors. You want the dead artist bonus on your collections.

But I like being able to buy new Smith and Wesson revolvers, from a Smith and Wesson company based in the USA, and even owned in the USA. And I think they're pretty nice, those new Smith and Wessons. I like being almost able to afford them too.

As other people have said in other contexts, Smith and Wesson is in business to manufacture and sell firearms, not to make collectors happy.

 

[Aussie44]

As other people have said in other contexts, Smith and Wesson is in business to manufacture and sell firearms, not to make collectors happy.


It has nothing to do with collectors..Smith & Wesson for over a hundred years built them one way forged,Firing pin in the hammer.Now they look like a Taurus,Have a lock which it doesn't need,As for Colt they didn't go out of business because they forged ,it was the Unions wanting more money for the workers and splitting the company that killed them,Winchester made cast ?? They are no more.

Ken

 

[stevieboy]

Gosh, it's been, what, nearly two weeks since we had a thread where people got to moan about the terrible events at Smith? Ironically, it was just this weekend that I took my 686-6, with its unpinned barrel, its unrecessed cylinder, its MIM hammer, trigger, and internals, and (oh, the horror of it all!) its lock, to the range, and for the umpteenth time, marveled at its accuracy and its smooth trigger. I'm such a traitor. Of course, I feel the same way about my pinned and recessed 66 no-dash, my 27, and my pre-lock, pre-MIM 617. They're all great in my book.

 

[Hunt200]

My 686 has MIM parts and is smooth as silk, I have pounded away with thousands of 38s and 357s with out a hiccup.

 

[Dennis The B]

MIM parts don't have the same crystalline structure as forged parts. There just isn't any way to get the same density with MIM as with forging. That stated, if MIM parts meet the same product standards as forged parts, at fractions of costs, why not use them?

Auto manufacturers have been using MIM parts in engines for years. The internal stresses on engines far exceed those of a hammner or trigger.

I agree that forged parts are more traditional, and that MIM parts don't have the romance to them that the forging process brings to mind. However, are we talking art or utility? What's the purpose of the handgun. Is it art to be admired, or a tool to be used for utility purposes.

Bill Ruger proved that investment casting could be used to create products which are every bit as utile as those forged.

Outside the firearms industry, golf manufacturers have been making investment cast irons for years, and they've pretty much replaced forged irons in the golfer's bag. Are they as nice looking? No. Do they get the job done better? Yes, because the investment casting process helped create a bigger "sweet spot", something forging couldn't do.

 

[haggis]

From the horses mouth...

This is an old post about MIM from Herb Belin of S&W that may shed some light on the subject...


I have read with much interest the many comments in this forum pertaining to MIM, MIM Parts and the use of same in a S&W product. So far I have come away with several impressions and they are "people in general don't like/trust MIM parts" and "no one has said why" I will take a stab at this issue and see where it goes.

As background to our decision to use MIM in some areas of our Mfg Process we took a long hard look at our "Life Time Service Policy". It was clear to us that any change in any of our products such as the use of MIM components had to show equivalent or better performance and durability to those components that were being replaced or the "Lifetime Service" would haunt us forever. The second consideration was to determine if the change was too radical a departure from S&W mainstream design.

For the performance and durability issues we decided that if MIM could be used for the fabrication of revolver hammers and triggers successfully this would truly be an "Acid Test". There is nothing more important to a revolvers feel than the all-important Single Action Sear that is established between the hammer and the trigger. Mechanically few places in a revolver work harder than at the point where the hammer and trigger bear against each other. If these surfaces wear or loose there "edge" the "feel" is lost. Initial testing was on these two critical parts. Over time we arrived at a point where our best shooters could not tell the difference between a revolver with the old style hammer and trigger and the new MIM components. Special attention was given to their endurance when used in our very light Magnum J frames such as the early prototype 340 & 360 Sc's. None of our revolvers work their components harder than these small magnum revolvers. Throughout this testing MIM held strong and finally we determined that this change judged on the basis of durability and feel was a good one.

The second area of concern to S&W was our customer's reaction to this departure from the traditional. Many heated, intense discussions resulted but in the end the decision was made to move ahead with MIM. The issue of cost was only one of the considerations in making this decision. Equally as important was the issue of part-to-part uniformity and the result of this of course is Revolver-to-Revolver consistency. We found that revolvers that used MIM hammers and triggers required almost no Fitter intervention in those areas during final assembly and final inspection and Trigger Pull Monitor rejection rates dropped markedly on finished guns. From an internal process point of view it appeared a "Winner".

Lets shift gears for a moment and talk about the MIM process. It is unclear to me as to the reason for many of the negative feelings on the forum concerning MIM. Typically when people complain and aren't specific in the reason why, the problem is often created by a departure from the "Traditional". Perhaps that is indeed what is bothering some people when they view MIM.

The term MIM stands for Metal Injection Molding. It holds some similarities to Plastic Injection Molding and many differences as well. To start we would take a finally divided metal powder. This could be stainless or carbon steel. Today even Titanium is being used in some MIM fabrications. We would mix the metal powder and a thermoplastic binder (generally a Wax) forming slurry of sorts when heated and inject this mix into a precision mold and finally form what is known as a "Green Part". This part is roughly 30% larger than the finished part it will become at the end of the process. Interestingly enough the Green Part at this stage can be snapped in two with simple finger pressure. The Green Parts are then placed in a Sintering furnace filled with dry Hydrogen gas and the temperature is brought almost to the melting point of the metal being used. Over time the "Wax" in the Green Part is evaporated, the metal fuses and the part shrinks 30% to it's final correct dimensions. At this stage of the process the MIM part has developed 98 to 99%of the density of the older wrought materials and a metallurgy that is almost identical. Dimensionally it is finished and no machining is required. However the job is not yet done and the MIM parts are brought to our Heat Treat facility for hardening and in the case of Hammers and Triggers, Case Hardening. Depending on the particular metal alloy that was used at the start of the process we apply a heat treat process that is the same as would be used if the material were the older wrought style. Final hardness, Case thickness and core hardness are for the most part identical to parts manufactured the older way.

Lets look for a moment at how we achieve dimensional precision when comparing these 2 processes. The old parts were each machined from either bar stock or a forging. Each cut and every resulting dimension was subject to machine variations, Cutter wear, operator variations etc. If every operation was done exactly right each and every time and the cutter didn't let you down you would have produced a good part but sometimes this didn't happen resulting in a rejected gun and rework or in the worst case an unhappy customer. With MIM parts you must still machine to very high tolerances and your cutters have to be perfect and your machinist has to be highly qualified but all of this only has to come together one time. That time is when the injection mold is made. Typically a mold for this process costs S&W between 30,000 and 50,000 dollars. Once it is perfect every part it makes mirrors this perfection and you have in my view a wonderful manufacturing process.

Hopefully this description will help us all better understand the MIM process.
Please forgive the spelling errors and misplaced punctuation. I have no spell checker on this and the phone continues to ring!

Have a Great Weekend,
Herb

Additional Point.
Currently S&W is paying about $1.20/Lb for stainless steel bar stock. Raw MIM stainless steel inject able material costs $10.00/Lb.


- Buck

 

[scooter123]

Gosh, it's been, what, nearly two weeks since we had a thread where people got to moan about the terrible events at Smith? Ironically, it was just this weekend that I took my 686-6, with its unpinned barrel, its unrecessed cylinder, its MIM hammer, trigger, and internals, and (oh, the horror of it all!) its lock, to the range, and for the umpteenth time, marveled at its accuracy and its smooth trigger. I'm such a traitor. Of course, I feel the same way about my pinned and recessed 66 no-dash, my 27, and my pre-lock, pre-MIM 617. They're all great in my book.

That about sums it up for me as well. Trigger pull on my 620 is nearly as good as my older model 67, which I strongly suspect was treated to an action job. In addition, 2 part barrel produces accuracy that is simply stunning when I do my job right.

 

[Bullseye Smith]

If it doesn't have a hump back hammer I don't want it. That was what was said after the war when they started the new type hammer and now we hear it with the new MIM hammers.

The MIM are the best for a target or race gun, I agree it's not pretty like a girl in Playboy, But I always liked the farm girls myself "LOL". If we don't support Smith and Wesson now, our grandkids with have to buy that inport junk like the cars. The new guns are better built than the old, but the old has that feeling of being hand built which makes them special. The ones built today will have that same feeling in 30 years. We have the best built revolver made in a Smith and anyone says other wise doesn't belongs here. I have over 200 revolvers in the safes and I can say with pride that they are all Smith & Wesson. I'm sorry If I pee in someones cornflakes, you will just have to live with the taste "LOL".

 

[gizamo]

John,

Good post. One point I would like to make. There is a relatively new firearms company...USFA...

U.S. Fire Arms - Old West Guns and Cowboy Action Shooting Rifles

They make Single Action handguns to very high standards. Frankly, I don't know how they can make such a fine firearm at their price point. I've handled a few and cannot tell you how impressed I am with their quality...line bored cylinders and fitment of the highest order. So it is still being done in the USA, at the very highest levels of standards.

Definitely on my short list...

giz

 

[Aussie44]

Your piss missed my bowl..As for not belonging here,Well thats not for you to decide Mate.My money and I will spend it the way I want,And I don't need a Taurus lookalike.The best Smiths were pre MIM and Pre frame mounted firing pin And pre lock,That's my opinion and I'll stick to it.

Ken

 

[gizamo]

Forgot to mention...USFA's is located ....at the old Colt Factory. In keeping with the companies interest in continuing classic American designs, the factory is located "Under the Blue Dome," the former site of the Colt East Armory, where Colt's Manufacturing produced many of their classic firearms in the late 19th and early 20th centuries.



giz

 

[lebomm]

Giz:
+1 on the USFA guns! I have one of their Bisley Flattop Targets in .44 Special, and it's a picture of hand-fitted artisanship! That and the fact that it shoots as well or better than my Model 24-3 make me quite proud to own it.

Larry

 

[i8mtm]

If MIM is so great....why do the Performance Center guns still use forged hammers & triggers?

I have both forged & MIM guns. I am not an expert shooter, but even I can tell a difference. The forged parts feel smoother.

My question is, how can a "trigger job" be done with MIM? I thought the case hardening of MIM is not as deep as forged parts and if one were to polish down past the case hardening on a MIM part, the wear would be very rapid.

I bought a used Model 60 that was sent by the former owner to S&W for a trigger job. The gun has MIM parts, and it definitely feels like it has had a trigger job. How do they do that? Do they file and polish the parts and then re-heat treat them?

Would this gun's hammer/sear engagement last as long as forged parts that have been polished and fitted? Just curious.

MIM is not a deal-breaker for me, I don't abhor MIM the way I do the internal lock. But I do prefer forged parts.