Conversation with MIM sales rep (long)

[Shear_stress]

I was at a recent trade show for more or less completely non-gun-related products when I stumbled across an unassuming, but very interesting booth. The fellow manning the booth represented a small company in Longmont, Colorado that specializes in the production of metal-injection-molded (MIM) parts. After all the debate on this forum and others about the extent to which MIM parts have ruined recent gun quality, I wanted to get the scoop from someone who makes these things. His opinions would not be impartial, but they would be interesting.

On the table was a wide and random array of "green" and finished parts. Immediately, I saw something that grabbed my attention: the trigger for an Accu-Trigger-equipped Savage rifle (you could tell by the slit for the "AccuRelease"). It was then that I noticed all the Smith and Wesson parts: revolver hammers and triggers, 3rd-generation semi-auto hammers, and numerous 1911 parts (hammers, sears, MSHs, etc.) After talking to the rep, here's what I found out:

1.) This company makes 85 different parts for S&W. I had understood that Smith made these parts in house, but I guess I forgot when century it is.

2.) In addition to S&W, the company makes parts for Savage, Remington, Mossberg, and even the late Winchester (he showed me the "end-cap"--not sure what to call it--of a Model 70 bolt).

3.) According to the rep, MIM results in parts with little or no porosity. He argued that recent advances have allowed them to produce parts with close to the theoretical densities (7.5-7.7 g/cc for most MIM steels).

4.) To pick a random example, the 2% yield and ultimate tensile strengths for MIM'ed 316L stainless (25 and 75 KSI), were no different than typical 316L steel.

5.) Their low-alloy ("MIM 46xx") steels are heat treatable to 48 HRC.

6.) The company makes parts for the medical-device industry.

7.) They have tried to eliminate visible mold parting lines. Yes, they are aware that consumers are very suspicious of MIM parts.

8.) Due to advances in the field, we can expect to see MIM parts that are larger and have different form factors than we are used to (slides or frames?)

All in all, it was pretty interesting. As for myself, I am still agnostic about MIM technology and tend to prefer older guns for subjective reasons--aesthetics, an old-fashioned sense of craftsmenship, etc. However, it looks like MIM is here to stay and will be popping up in unexpected places.

Just thought I'd pass this on.

 

[Car Knocker]

Thank you for relating your conversation.

 

[MarshallDodge]

I am familiar with that company. They were one of my customers when I lived in Colorado and have a good reputation.

My thoughts on MIM are positive. I have quite a few guns with MIM parts and have had zero issues. The look of a machined part is better, especially with a high polish and good bluing.

It does not matter if the part is MIM, cast, or machined. If the process has a quality control issue then the parts that come out of it will be flawed. I have seen machined parts fail because of a glitch in the heat treat process.

 

[fastbolt]

I've observed no particular issues with MIM parts in the S&W and Colt pistols I help maintain and personally own. FWIW, I've seen more issues arise with forged & cast parts over the years.

I remember asking someone from the S&W factory how things were going with their usage of MIM parts last year, and I was told that the factory continues to be pleased with the quality of the parts produced for them, and that they maintain ownership of the MIM molds used to produce their parts.

 

[PracticeFreedom]

Count me as in the dislike-MIM camp.
The problem I have with MIM has nothing to do with close-fitting/tolerances or price. It's the way MIM parts catastophically fail with no warning. Happened no less than 3 times, on 3 different parts, on a Para-junk P14 Limited I had the misfortune of owning (safty lever, slide stop, firing pin stop) That little lesson caused me to go over my other 1911s very carefully, replacing any cast or MIM internal parts, pins and levers.

MIM has its place, but IMO, doesn't belong on ANY internal, or stress-heavy firearm part.

I've been told that the reason for this type of failure has to do with the way flaws develop in the MIM process. Apparently, unlike say castings (who's flaws are usually visible), flaws in MIM parts are not apparent until the part is stressed/used (like firing a gun for the Nth time) As MIM parts aren't individually tested (this would cost $$ and the whole point of MIM gun parts is cheapness) you can get "lucky" as I did. I'm no metalugist, so I don't know if that is true, but I do know that the Para I owned had 3 MIM parts that failed with less than 500 rounds through the gun.

 

[fastbolt]

Lumping all MIM parts together is like lumping all cast, forged, extruded, machined, etc., parts together.

The quality of the materials used and the quality control involved with the specific manufacturing process are also very important. However, in some respects you may only get what you pay for, as with some other things ...

There's forged, and then there's forged ...

There's cast, and then there's cast ...

There's MIM, and then there's MIM ...

There's ammunition, and then there's ammunition ...

The last several parts I've had to replace on various firearms were all produced with other than MIM.

Quality of manufacture and component application are important.

There are a couple of things I don't necessarily like when it comes to MIM parts, but the manufacturers seem to be improving their MIM offerings and I've learned to trust QUALITY MIM parts in certain applications.

 

[HankB]

I'm not a metallurgist, but my impression is that

* Top-quality MIM parts are better than low quality forged & machined parts.
* MIM parts are not suitable for the most highly-stressed parts, such as the aforementioned 1911 slide stop and springy things like 1911 extractors.
* NOBODY claims even the best MIM parts are as good as, let alone better, thaN the best forged & machined parts.

 

[jeepmor]

Like an engineering endeavours, quality control is the key. As new technologies come out and mfrs try them to save a buck or two, people who are willing to buy new things get to play guinea pig. That's just the way it is, the way it's always been.

People used to think the car would never replace the horse and buggy....see any horse and buggies on the highways lately? The Amish don't like mim, or rubber wheels for that matter, so let's leave them out.

I would really like to work for a company conducting this type of engineering, it would be a nice change from my current role in semiconductors measuring things your naked I cannot even begin to see.

 

[Old Fuff]

If you happen to lay hands on an older S&W revolver you may notice the (then) trademark color casehardened hammer and trigger. The oil-slick colors add a quality appearance to the gun, as well as being functional.

Today's MIM lockwork may be functional, and it's still casehardened, but the colors are muddy-gray because the parts don't color when they are hardened. They also don't burnish or polish as smoothly as well as the "all-steel" parts used formally.

They are to be blunt, cheaper subsitutes. They are being used because they cost the manufacturer less. When MIM makers can duplicate the older parts in all respects I might get interested.

But they aren't doing that now.

 

[Flame Red]

Remember that MIM is used because the process makes the product less expensive to manufacture - NOT TO IMPOROVE THE QUALITY.

Just another technique so they can give thier CEO's a bigger retirement golden-parachutes. Like my CEO that just walked away $158M, and his anual golf club membership they also threw in of $25K/year will be more than any pension I will ever see even after 30 years.

 

[Onmilo]

Regular floor workers still get pensions somewhere???

Our Factory took that away when the last contract was ratified.

MiM is popular because the Chinese and India are buying up all the steel they can get their hands on and MiM is a cheaper alternative.

It is in no way better than forged and machined steel.

 

[5Wire]

Thanks for the informative post, Shear_stress.

 

[Shear_stress]

I knew this would generate a lot of debate. Let me be, if not the first, then the millionth gunowner to say I do not particularly like MIM parts. I don't like the way they look, I don't like the fact that MIM parts are cheap but guns are not (at least in non-adjusted dollars, see below), and I don't like the fact that MIM parts are not hand-fitted by craftsmen/women. Among the reasons I love guns is the fact that, despite the encroachment of mechanization over the past two centuries, the way guns were once made spoke to a more time-honored sense of quality and workmanship.

. . . However, I fully acknowledge that the above are subjective--matters of personal taste that heavilly influence what I choose to put in my gunsafe (which is populated almost entirely with used guns). In addition to being a gunlover, I am also an engineer who seeks to evaluate things based on objective, data-driven criteria. Because of this, I find myself in the unusual position of defending MIM against statements like this:

MIM is popular because the Chinese and India are buying up all the steel they can get their hands on and MIM is a cheaper alternative.

Really? A steel MIM part is still made from steel. The density of a properly finished MIM part is, for all intents and purposes, the same as one made from barstock. What MIM saves is not material but labor (see above, re: craftsmenship.)

It is in no way better than forged and machined steel.

No one is arguing that it is. The point I'm trying to make is that there is no evidence that, from a purely mechanical point of view, MIM parts are inferior to forged parts.

Remember that MIM is used because the process makes the product less expensive to manufacture - NOT TO IMPOROVE THE QUALITY.

This is correct, but, again, no one is saying that MIM parts are better--only that they aren't necessarily worse. On the other hand, I'd be willing to bet that most modern gunbuyers wouldn't be willing to lay down the dough for new guns made "the old way". Just ask Colt. This isn't so much of a problem right now while there is so much good stuff on the used market, but it may become a factor years later.

I share many folks' gut-level dislike for MIM. For exactly the same reasons, I don't like plastic pistol frames or rifle stocks (why buy plastic that costs pennies on the dollar to squirt into a mold when I could buy something forged from metal or hewn from wood?) I've only recently come around to investment cast frames (why do the anti-MIM folks never carp about Ruger, FN, Caspian, or Freedom Arms for that matter?) All I am trying to do is add a few data points into the debate here and there for consideration. I think folks should just be honest with themselves as to their preferences.

 

[FullEffect1911]

There is one sad truth about the world we live in today, American manufacturers need to find a way to compete with the rest of the world. Other countries (China for example) currently has much much much (did i say much) lower wages then we Americans do. Wages are usually what drives the price of things up. In order for American manufactures to compete they either have to move their manufacturing overseas, or find a way to do it differently/cheaper.

The U.S. has to stay ahead of the game through technology now a days, cause I wouldn't be happy making a dollar a day. And eventually when China's wages start to catch up, there will be another country with cheap labor to take it's place.

New technologies take time to get all the kinks out. And I would not commit to saying that MIM is bug free at this point... but they are getting there.

I would rather see MIM part in our firearms then see some of our most historical firearm manufactures go out of business.

I think in another few years, it will be quality parts will be quality parts despite how they were made.

 

[DawgFvr]

Does Ruger use any MIM parts?

 

[MarshallDodge]

I don't know about MIM but they do use a lot of investment cast parts.

Once again, this may not be a bad thing if it is a good design using an efficient quality control system.

 

[Nightcrawler]

Does Ruger use any MIM parts?

No. But nothing Ruger makes is forged, either. It's all investment castings.

 

[Boats]

Ruger just happens to make some of the best investment castings the planet has ever seen, which are magnitudes of order better than MIM parts.

 

[Shear_stress]

Ruger just happens to make some of the best investment castings the planet has ever seen, which are magnitudes of order better than MIM parts.

So, one great implementation of a molding technology invalidates an entire alternative molding technology? Both investment casting and MIM involve squirting a liquid into a mold, though the former is usually under a vacuum and the latter under positive pressure. Neither involves coldworking. If anything, Ruger's excellent cast parts should make Ruger fans less suspicious of molded parts in guns. As has already pointed out above, it's often not the technology, it's the implementation that matters.

See, this is the kind of stuff that prompted me to start this thread.

 

[MarshallDodge]

Ruger just happens to make some of the best investment castings the planet has ever seen, which are magnitudes of order better than MIM parts.

Do you have facts to backup this claim?

 

[Nightcrawler]

Yeah...has anyone actually scientifically demonstrated that investment castings are better than metal-injection-molding, given the same levels of quality control? Has anyone scientifically demonstrated that either of these are inferior to forged materials, in terms of how they're applied to firearms? (I.E. can you prove that a cast hammer or a MIM hammer is more likely to fail or break than a forged one?)

It seems to me that if they can make major firearms components out of plastic, then making them from castings or MIM doesn't necessarily mean they're more prone to failure.

 

[Boats]

Scientific proof? Look at the state of the two technologies. Investment castings, including those made by Ruger's Pinetree facility, are routinely used in high stress aerospace applications, such as jet turbine blades and other highly stressed internals of jet engines.

MIM is generally limited to dimensional small parts that weigh less than an ounce. Its only advantage over IC is the elimination of finish machining, which is a considerable cost savings on things such as small parts. I'd still rather have an IC part vacuum formed over a baked sintered metal MIM part.

Even where MIM is being experimentally scaled up for larger parts, such as by Honeywell for use in jet flow covers, they daren't use it in a moving part as it seems only suitable for taking passive temperature stresses not mechanical stresses.

MIM might one day be a top shelf production process, but right now it's just a cost cutter that can't generally be trusted in a part over an ounce in weight. Undetected voids inherent to the manufacturing process being the main culprit.

 

[Shear_stress]

Scientific proof? Look at the state of the two technologies. Investment castings, including those made by Ruger's Pinetree facility, are routinely used in high stress aerospace applications, such as jet turbine blades and other highly stressed internals of jet engines.

Absolutely, but, again this is an example of an implementation of a mature technology. The types or processes and controls used to make investment cast turbine are not the same as those used to make gun parts. The fact that investment casting can be used to make aerospace or mil-spec parts does not automatically mean that such parts are comparable to golf clubs or gun frames. My point is that you can't use one example of a use of a forming technology to either praise or bash everything made that way. How many single crystal Ruger pistol frames are out there?

Even where MIM is being experimentally scaled up for larger parts, such as by Honeywell for use in jet flow covers, they daren't use it in a moving part as it seems only suitable for taking passive temperature stresses not mechanical stresses.

You are right again, but the fact that MIM parts have been difficult to scale up doesn't mean that, for the applications they are used for, they are inferior. S&W uses MIM for lock-work, not pistol frames (which investment casting works fine for). All forming technologies have their limitations.

MIM might one day be a top shelf production process, but right now it's just a cost cutter that can't generally be trusted in a part over an ounce in weight. Undetected voids inherent to the manufacturing process being the main culprit.

See point #8 in my original post. Technology improves. Remember that, once upon a time, investment cast pistol frames were a cheap alternative to forging. You know, the kind of thing that a start-up company like Sturm Ruger might use (and eventually perfect.)

 

[BigG]

{MIM parts} They are to be blunt, cheaper subsitutes.

I don't think anybody didn't know that. The difference between an enthusiast and a businessman is the enthusiast doesn't have to make money. The businessman has to pay dividends to his stockholders, give his workers a raise, pay the operating costs and buy material. People that believe a businessman is ripping them off because the weapon is not built with 1957 technology ought to drive a 57 Chevy and work for 1957 wages.

 

[Onmilo]

1957 era technology produced the M14, the oil tankers that bring our precious fuel and that wonderful 1957 Chevy which in all ways except safety, (no seatbelts), was a better automobile that what we have today, oh wait no unneccessary GPS and no cupholders.
Heck I don't even want a sattelite I have never met being able to track my vehicle at any given time.

As for 1957 wages, adjust for inflation and I actually I earn LESS than what a 1957 era factory worker did and current CEOs earn 10,000 times more than a CEO did in 1957.

Ever tried cleaning up a sear or a magazine release made out of MiM material?
The heat treat is a mild surface application and cannot be worked without reducing the structural integrity of the part.
Forged steel can be worked down past the heat treat too but if you do this it will be so out of tolerance the part will no longer function as it should.

As for the density of a similar MiM fabricated part being consistent with a forged solid steel component, so what?
Density does not make a structurally stable steel part.

Lead is denser than steel, put a torch to an identical lead part and an identical steel part and see what happens and when it happens.

MiM is a cheap way to make an expensive gun. Sure looks grand to the stockholders anyway,,,,,,,,