MIM vs. Machined

MIM parts cannot be hardened.
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From what I read they can be hardened. This is the link I posted in one of my above posts.

http://machinedesign.com/article/mim-machining-matchup-1020

There are several MIM stainless and low-alloy steels that can produce parts with enough hardness (40 to 44 HRc) and tensile properties on the order of 150 to 200 kpsi (1,030 to 1,380 MPa). Tests of MIM 17-4PH H1025 at 98% theoretical density, for example, showed that 50 consecutively molded tensile bars had similar mechanical properties to those in published guidelines. Other commonly MIMed materials which attain enough hardness include MIM 4140 and MIM 4605.
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I also don't see the big deal about MIM parts. The only part on a firearm of mine that has broke in the last 5 years was the extractor on a Glock 20. Don't know if it was MIM it not. It broke under the 150 round mark. I called glock. Had a new one in the mail box within a week.

Machines break. No rhyme or reason to it.
 
Maybe people like to jump on a bandwagon on controversy. Who knows...
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You hit the nail on the head I think. My dad is a senior engineer for Whirlpool. He designs washing machines and dishwashers, and he sees this a lot in design circles. Something is new, so the failures are far more scrutinized than the old tried and true method. This doesn't mean that the old method was better or failed less however. More often than not the new method is just as good, if not better, and costs less. People eventually "get over it" and move on, just like polymer frame pistols. Today it is MIM. 10 years from now when there is a new process, the MIM debate will be overshadowed by it and you won't hear about how evil it is, or how failure prone it is, because the new process will be "the devil".
 
The post about pre-war S&W revolvers reminds me that when S&W switched from the so-called long action to the short action sometime after the war, there was suddenly a demand for the old style action because some experts decided they were better, smoother or something. Of course you already knew the pre-war stuff was better anyway.
 
2003flht writes:
I've seen alot of bashing about MIM parts. I was wondering why people hate MIM so much. Is it a cosmetic thing? Durability? Mis-conception?

Being in the aerospace industry, and being a machinist/tool designer/engineer, I've seen technology advance through my years. I was amazed when I saw what resembled a inkjet printer produce a plastic part from a CAD model, a tank of yellow liquid goo that when a laser beam was applied, made highly detailed plastic parts. Then I was involved in SLS (selective laser sintering). I was amazed what could be done with powdered metal.

Now, we have metal injection molding... I have seen parts made this way that conventional machining could never do, or it would be so cost prohibitive. MIM is an advanced technology that keeps getting better as time goes. These MIM parts are used in aeroplanes and advanced fighter jets. Why wouldnt they work in a firearm?

I mean, if they use MIM parts in jet engines at 30,000 feet going Mach 2, what makes people think MIM parts are inferior for a firearm?
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Thank you very much for posting this. As a member of the aerospace industry myself, I have never seen an increased failure rate of MIM parts and the guns I own have never had a failure of MIM parts.

The truth of the matter is that there are people lurking within the Forum who cannot wait to find something to pounce upon and bash. Makes no difference whether it be MIM, Glock, Kimber, etc. They are the 3 percenters who are never happy people, always looking for something negative and adding nothing constructive.

I have learned a lot from reading this Forum, and others like it, as there are so many very intelligent people willing to share their expertise and knowledge and I am grateful to each and everyone of them. Then there are those that will bash anything because it seems to be a popular thing to do and have no real experience; only what they have heard. It make the world go around and for those of us looking to garnish something positive, it sharpens our awareness of what is real and what is contrived.
 
From what I read they can be hardened.
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No, they are produced in the proper hardness. They are not hardened after-the-fact. They cannot be welded.

My biggest gripe with new S&W's, other than the infernal lock, is that while they are manufactured more cheaply, they are still expensive. Costs have not come down and MIM parts greatly reduce labor and manufacturing costs.


Of course you already knew the pre-war stuff was better anyway.
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The fact that most people don't know the difference does not mean the difference does not exist. In a world of revolvers with laser sights and rubber grips, I'm not surprised that the finer details are lost on most.
 
I'm not surprised that the finer details are lost on most.
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Well, it depends on what your purpose for owning a firearm is in the first place. Are you looking for a reliable tool, or are you a collector? That right there will determine whether or not you like the current breed or not.
 
"IM". That is, injection molding. From that point on it does not matter how good the process actually is. We, the traditional lot we are, will always associate "injection molding" with plastic. Which equals "cheap".
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Whatever the superlunary and quintessential TRUTH about MIM parts might be, those of us who don't want them are able to avoid them simply by avoiding manufacturers who use them. By and Large, custom pistol and revolver smiths don't use them at all. I've even heard that the Smith and Wesson custom shop throws out the MIM parts and replaces them with earlier technology. I don't expect to ever know if this is a decision in favor of quality or some sort of religious thing.

It does seem that Ruger has optimized its products for investment casting and MIM while old single actions, handejectors and 1911s evolved when forging was the prefered process.
 
MEC is correct. The S&W Performance Center actually boasts that there are "Forged parts only" in their pistols. Wonder why they do that? Given the obvious superiority of MIM as told to us by experts here, why not put MIM parts in those expensive PC pistols and revolvers?

Anyone see where S&W is having problems with the MIM strikers in the M&P pistol breaking? The replacement striker is stainless steel. Why not just come up with another MIM striker?? :rolleyes:

MIM is not the deal breaker, for me, that the lock is.

I have had two MIM parts break though. The thumb safety on a Kimber Stainless Target II, and the mag catch on a S&W 4516-3.

I think if MIM is done right, you are unlikely to have a problem. But to declare that it is not a cost cutting measure by (insert your favorite manufacturer) and superior to forged parts is ludicrous.

Then again the "brand loyalty" that I see displayed over and over, on this and another board, by the same folks, no matter what turds their favorite manufacturer turns out, is ludicrous to me as well. Regards 18DAI.
 
I've got one question - what process was used to manufacture the the locking block mechanisms in the 1990's Beretta 92 and Taurus copies? It was some kind of casting, I know that, becasue the replacement locking block was really rough looking and the casting seams were over 2mm deep in some places. The seams had to be ground off by my gunsmith.

In other words, they fit like crap, looked like crap, and were prone to breaking. So, I guess I equate "casting" with Taurus locking blocks. There's no science behind this opinion, just personal experience.
 
Its perception ..... and perception of strength and quality...

Not all MIM parts are bad - not all cast parts are bad - and all machined parts are not good. But I do think when MIM parts first came out - we did see some failures and that perception of "cheapness and poor quality" lingers.

All things being equal - I'll stay away from a gun with MIM parts, cast parts and poly frames - at least for now. But in the 70's, I thought all japanese cars were junk too....but Lexus has changed my mind on that as well. I may change my opinions on MIM, cast and poly frame down the road too ...but don't hold your breath...(and I can't bring myself to buy any of the newer S&W revolvers with the internal frame locks either - but I love my older S&W revolver collection of model 19's, 27's, 28's, 29's, 66's, 686's, 629's ....). But I know I'm a dinasauer too ....and I like it this way.
 
The question is not why use of MIM and other modern techniques have not lowered costs, it is how much the guns would cost if made by the methods advocated by CraigC and mec. A $3000 Model 642 anyone? Hand fitting is hard and tedious. In the 1900's skilled workers were paid $2-3 a day, it went up to about $5 in the 1920's. I don't think the "hand fitted only" folks would work for that at whatever they do. Read my previous post and become familiar with the insides of both the old and new guns. I used to hate having to deal with those tiny springs and microscopic pins.

P.S. A big chunk of the price of a new handgun goes for insurance to protect against the kind of lawsuits intended to end firearms manufacture in the U.S.

Jim
 
Chances are, custom gunsmiths don't use them (that is, don't make them) is because they can't afford the technology. While this sort of thing is one way of lowering costs, it generally only makes sense for high volume work. After all, if you use computer controlled equipment for metal shaping, you still need the equipment itself, plus all the electronic stuff, and you still need an operator. Same thing with all the other methods.
 
MIM is like many other things.

Used correctly with good QC it produces very good parts, some that could not be made any other way.

Done incorrectly their can be voids and poor parts subject to all sorts of defects.

It is painfully expensive to set up for, and not really suitable for small shop use.

The machines need to be kept busy to make any money back.
 
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