Bad Rugers with MIM parts?

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against my better judgement I will repost Grant's explanation


The trouble is that the MIM part is the same hardness all the way through, since that's how it was engineered. This is great for reducing sear face wear, but with hardness comes brittleness - and that thin edge is quite brittle. What you need is a surface hardening of some sort for wear resistance, with the underlying material left softer for strength.
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This is the money shot on the subject from a gun expert of impressive renown.
 
The trouble is that the MIM part is the same hardness all the way through, since that's how it was engineered.
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quote by grant which at the time the article was written may have been true but it doesn't jive with this quote on he link I provided
MIM parts are sintered at temperatures nearly high enough to melt the entire metal part outright (up to 1450 degrees Celsius), at which the metal particle surfaces bind together to result in a final, 96-99% solid density. The end-product MIM metal has comparable mechanical and physical properties with parts made using classic metalworking methods, and MIM materials are compatible with the same subsequent metal conditioning treatments such as plating, passivating, annealing, carburizing, nitriding, and precipitation hardening.
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just for conversation sake I emailed the company and asked about hardness and wear resistance of their MIM products if they respond I will post the response. And with that I am out as I was about to go to sleep an hour ago, :) but its a good conversation MIM is a part of the production of many things and is relatively new.
 
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Guillermo said:
against my better judgement I will repost Grant's explanation

The trouble is that the MIM part is the same hardness all the way through, since that's how it was engineered. This is great for reducing sear face wear, but with hardness comes brittleness - and that thin edge is quite brittle. What you need is a surface hardening of some sort for wear resistance, with the underlying material left softer for strength.
Click to expand...


This is the money shot on the subject from a gun expert of impressive renown.
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As I have noted before when G-Man has made reference to this is that in this paragraph, Grant is referring to the spring like sears of auto-loaders......and of no significance when talking about revolvers as we have been here. Grant in the same linked article also contradicts the suggestion made here that MIM is just a "cheap" alternative. Apparently some folks only read what they want, or have a poor sense of comprehension.


The advantages of an MIM part do not generally include raw cost; the material is expensive, and the molds are horrendously expensive. The benefits come in the area of post-fabrication. The MIM part, as noted, can be heat treated - the benefit is that they don't need to be, as the hardness of the part can be engineered in when the part is made. The parts come out ready to use; no additional surface finishing is generally needed. Finally, the parts can be made in shapes that would be extremely expensive or nearly impossible to economically machine.

The downsides? Cost, as already noted. Additionally, the tolerances for an MIM part generally need to be larger; it's hard to hold them to .001" in all dimensions (though they're getting better all the time.) Another problem is that the technology doesn't work all that well for parts that are more than about 3/8" thick (again, this gets better on an almost monthly basis), nor on stressed parts that are very thin.
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Again as Grant states, the quality of MIM fabrication gets better and better on a monthly basis. The linked article is from 2006.........


just sayin.
 
the fact remains the same, no matter what the part, the way that gun companies produce them, the hardness remains the same all the way through.

This does not vary as to the quality or type of part.

It doesn't have to be that way. They can create a soft core and hard surface. They do not do so because of cost.

Again, this is not a problem in a value gun like Ruger. In fact, it is probably an improvement over the cast part it replaces.
 
Quote:
Originally Posted by CraigC
His data conflicts with crap you found on the internet.
^^^hahahaha!!..awesome..
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so Im guessing no one bothered to read any of the "crap" filled links but instead rely on an article written in 2006, interesting.
 
MIM parts are sintered at temperatures nearly high enough to melt the entire metal part outright (up to 1450 degrees Celsius), at which the metal particle surfaces bind together to result in a final, 96-99% solid density. The end-product MIM metal has comparable mechanical and physical properties with parts made using classic metalworking methods, and MIM materials are compatible with the same subsequent metal conditioning treatments such as plating, passivating, annealing, carburizing, nitriding, and precipitation hardening.
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Is this quote false? Because every website about MIM that isn't a gun forum has info like this. so maybe I am reading it wrong. please, is this incorrect?
 
Lobo,
that is not a false statement. It is a general sleeping statement. It certainly can be true. It depends on what the engineers specify.

In the case of turbine blades it is a three-step process, they are very strong yet flexible.

In the case of handgun parts, is a one step process and since the surface has to be very hard, the entire part is very hard.

This hardness makes them Brittle. Not excessively brittle, or they would all fail. Instead just some do. But that is the case with any part made by any method.

That said, it is still a good way to make inexpensive, uniform parts.

It is not the best way, but in some instances it is the best compromise.

My guess is that Ruger did their homework and this part is an improvement over the cast part which it replaces.
 
Guillermo said:
That said, it is still a good way to make inexpensive, uniform parts.

It is not the best way, but in some instances it is the best compromise.
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But again, as per your link, the process nor the materials are inexpensive, and as Grant states "the parts can be made in shapes that would be extremely expensive or nearly impossible to economically machine." In other words, not the best compromise, but the best way to manufacture quality affordable firearms. Again as per the Grant Cunningham link you provided for us.

The other issue I have with many of the posts in this thread is that it's fine for Ruger to use MIM with their cast frames, but it's not okay for S&W and other manufacturers to use it with forged frames. This comes as many state that since Ruger is such a great value selling for much less than others it should be expected. Have folks looked at list prices of comparable revolvers from Ruger and S&W? In most cases the difference is negligible and in some cases, the Rugers are actually more. The price point is a moot point. Truth is, the technology is there that MIM should be acceptable for any manufacturer to use, as long as they use it in the right application. Cunningham was right, it did not work well for auto-loader sears and most manufacturers have learned that lesson well. Reliable manufacturers that stand behind their products with great customer service(Ruger, Colt, S&W) apparently have great confidence with their MIM parts. The problem seems to lie with the internet gurus.
 
The Old Fuff is clearly one of those Internet gurus that no one should pay attention too... :uhoh:

But for the handful that do, I have several concerns about MIM parts.

In the good ol' days these components were manufactured "in house." Now they are usually made by sub-contractors, who are sometimes (if not often) picked for offering the lowest bid, which sometimes does not represent the level of quality I insist on. Unlike aircraft parts such as turbine blades they do not go through 100% x-ray inspection.

If not perfectly made, sharp edges, such as the edge of the full-cock notch on a hammer and tip of the sear may chip or crumble. You can also get a weakness in a seam of the matrix (metal particles + binder) if it is not perfectly mixed before it is heated.

While it is not of compelling importance, the parts themselves look cheap, and do not compliment a quality revolver. This of course makes me a gun snob, and I carry the title proudly. :cool:

The manufacturers often make the point that MIM parts are so precise that semi-skilled workers can assemble the guns they go in. Somehow I do not find this to be assuring… Skilled and experienced workman who hand fitted earlier guns were expensive – for very justifiable reasons, one being that they often spotted issues that had been previously overlooked before the product went out the door.

But for those who neither see nor care about all this there is no reason to not buy the current guns. There must be a lot of you because the company’s stock prices are going through the roof.
 
but the best way to manufacture quality affordable firearms
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Yes...it is an inexpensive way to produce a part that is relatively precise and requires no fitting. (thus saving enough money on labor to more than make up for the more expensive raw material)
Not the "best way" but the best way to save money so as to make your firearms "affordable".

No one who knows anything about the process argues that it injection molding produces the finest part. It is "good enough" and "cheap".

Same thing with Ruger using cast frames. He never claimed it was the best way. He used more than enough material and removed the sideplate to make up for the material.

Quite intelligent method of producing a strong gun at a cheap price.

Ruger has always attempted to produce good guns at reasonable prices. I think they do a fine job of it.



Such methods are to save money. When those savings are passed on to the consumer, I am all for it.

When such cost cutting methods are not passed on, I am not.

Put another way...vinyl makes a good seat cover. Easy to clean, durable. But don't charge me for leather.
 
to back up a bit the statement you are referring to as a "general sweeping statement" is not a general "sweeping statement" it is a fact of MIM production. It certainly can be true, because it is true.

Not excessively brittle, or they would all fail. Instead just some do. But that is the case with any part made by any method.
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your quote sums it up MIM parts where applicable are equal to the same parts made by different means. so which is "better"?
MIM is less expensive production for many reasons, One not being that they are inferior when properly produced and utilized. If you don't want them don't buy them.
 
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Old fuff you make good points but you are referring to improperly made MIM parts which can be true of all things made of anything. For example Century Arms some are awful, some are awesome, and some are passable. If made wrong they suck, if made right they work. Bad example I guess.... hey best I could come up with :)
 
But, on a more important note- Guill, how do MIMs hold up with .38 Special +P loads? :D
Denis
 
Lobo,

you seem to not want to understand.

I have repeatedly tried to explain how MIM parts are the same hardness all the way through as produced by gun companies. This makes them brittle.

It seems that you are trying to justify MIM. That is fine. It is your right.

But understand that NO ONE believes that MIM parts are better quality than forged.

No ultra premium weapon has them.

MIM is a solution to a problem that has to do with LOWERING costs. It is not a bad solution in order to cheapen guns...but it is not a method to improve quality.
 
And you fail to see part of my argument that when utilized in some gun parts a MIM part is equal to the same part created by a more expensive method that may require a more skilled laborer. And that could be where we agree to disagree and have no other choice but to come back 5,10,15,20 years and see how MIM parts have held up compared to their more expensive counterpart.

and one more quick point already pointed out earlier in the thread by someone else, Sintering that you spoke of that Colt was doing was not the MIM that we chat about. and I'm guessing colt made many errors besides that resulted in them not making DA revolvers anymore.
 
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As far as hardness is concerned. MIM parts can be hardened and annealed so if gun manufacturers decide not to its not the fault of the MIM :) may the MIM be with you.
 
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