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What are MIM parts?
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codasmog
Member
Metal Injected Molding
bigshot500
Member
so its a cast part like ruger uses...
OP
Ruger calls it "Investment Casting"
Pisgah
Member
MIM is similar in some ways to investment casting -- it does use a mold -- but much more akin to plasric injection molding.
Powdered metal, mixed with a plastic or wax "binder", is injected in liquid form in to a mold. The mold and contents are then heated to a high temp that drives off the binder and fuses the metal particles in to a solid piece. The result is a part that is as strong as most other types of metal parts, and very, very close to a finished product requiring little or no machining and/or finishing.
Powdered metal, mixed with a plastic or wax "binder", is injected in liquid form in to a mold. The mold and contents are then heated to a high temp that drives off the binder and fuses the metal particles in to a solid piece. The result is a part that is as strong as most other types of metal parts, and very, very close to a finished product requiring little or no machining and/or finishing.
leejack
Member
Made in Mexico.
Sorry guys, too much coffee this morning! LOL!
Sorry guys, too much coffee this morning! LOL!
leejack
Member
^ You caught that, huh? LOL!
slabside2
Member
Something you don't want. Look for one of Smiths older guns if you going to buy one. It just one more way for them to save a buck. But you won't. There prices just keep going and up and the way they are made keeps going down. In a couple of years who knows you may see MADE IN CHINA stamped on the the barrel. And the unions will get the blame. Maybe it's just me.
Pisgah
Member
This is the same stuff people used to say about Ruger firearms with their investment-cast parts. I don't know of many people today who would say the same about them.
bk43
Member
Investment cast parts have been around a long time and more will probably recognize the more common term lost-wax. They are the same thing and not the same as MIM manufactured parts.
I like the action on MIM guns as the close tolerances make for a smoother action right out of the box. The strength seems to be there but even if it turns out it's not down the road no big deal. S&W warrants the parts so the fix is on their dime.
Bob
I like the action on MIM guns as the close tolerances make for a smoother action right out of the box. The strength seems to be there but even if it turns out it's not down the road no big deal. S&W warrants the parts so the fix is on their dime.
Bob
slabside2
Member
Its not just the MIM parts it's the way the newer guns are made today.ask you self would you trade your new smith for one of the older ones??
Black_Talon
Member
Here's the MIM section of our very own Forum FAQ:
http://smith-wessonforum.com/report.php?p=1029055
Tons of other interesting info in the FAQ as well.
http://smith-wessonforum.com/report.php?p=1029055
Tons of other interesting info in the FAQ as well.
Pook
Member
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I got rid of an older Smith for a new one. as I mentioned on two other posts (http://smith-wessonforum.com/s-w-revolvers-1980-present/179448-classic-s-w-model-27-four-inch-2.html) and (http://smith-wessonforum.com/s-w-re...4-many-people-buying-new-s-w-revolvers-5.html) I had a mid-1970s-vintage ANIB nickel Model 58 that had "Monday morning hangover" (read "terrible") workmanship that I gladly sold to buy a new M58 nickel "Classic," whose workmanship is flawless. Although it has an MIM hammer (strangely, it has a forged trigger) and an IL, I want quality and craftsmanship more than I want or care about vintage or a pinned barrel, counterbored chambers and other superfluous "hallmarks" of the older guns. I want a S&W that has the great finish, fit, and overall quality, pride, and workmanship that "is Smith & Wesson." If an older S&W has these qualities, which none of my purchased-new 1970s guns had (they were awful), even though they were pinned, c'bored, no IL, No MIM, ad nauseum, I will give them an honored place in my family. If, on the other hand, they do not, they are dumped faster than you-know-what and then replaced with a S&W that does meet my expectations, and if I find those expectations are met with a new S&W, then that's what gets added to my family.
'Nuff said
God Bless,
Pook
scooter123
Member
MIM firearms components had some serious issues when they were first introduced and this earned them a bad reputation that carries on with some gunsmiths to this day. If not "cooked off" properly or if the base material isn't well suited to the use, a part that is brittle and fails quickly is the result. BTW, these parts were first offered for the 1911 platform and some custom crafted 1911's caused serious issues between the gunsmith who build the gun and his customer, so it's no wonder that some gunsmiths still deride MIM components.
However, S&W was a bit late to the MIM game and they took the time to work with their material suppliers and their process Engineers to make sure they "got it right". I've seen one single posting about an MIM part failing and that was a hammer spur that shear off after many thousands of dry fire cycles without the use of snap caps to cushion the fall of the hammer. Note, just ONE SINGLE FAILURE in two years on a very active forum and it was most likely the result of what many would consider abuse, including the person who posted about that broken hammer spur.
I'll also point out that about 1 1/2 to 2 years ago a member who knew one of the S&W engineers involved in the MIM implementation described the testing that S&W subjected the parts to before making the change from forged to MIM. Basically, they ran MIM and Forged parts in a parallel test that cycled these parts for many many cycles, my memory has the total cycle count being in the millions but I aint got the best memory, it could have been in the 100K range. After all these cycles the MIM and Forged parts were then checked and compared microscopically. The result was that the MIM parts showed LESS wear than the forged and no MIM parts failed during the testing. I suspect that 100 years from now collectors will prefer MIM guns over any other type because they'll stand up better than the forged parts.
As for why, it's pretty simple. MIM allows the material to be fully Engineered for function and structure down to microscopic levels, meaning it's a FULLY Engineered product. Unfortunately, Forged steels can't be fully engineered down to microscopic levels, to some extent "Pot Luck" is in play. BTW, I've had personal experience with that Pot Luck, you should see what happens with you try and drill and tap a hole in a piece of forged steel that has a chunk of tungsten carbide imbedded in it, end result is that nearly finished workpiece goes in the scrap hopper and you start over.
Bottomline, MIM from Smith & Wesson is MIM that has been done correctly. This means that it's as strong and probably stronger than forged steel and contains wear resistant particles in it's engineered matrix that will allow it to last longer than forged parts. IMO, MIM is Win-Win for all concerned, we get a longer lasting gun and S&W no longer has to individually fit each hammer to it's mating trigger. I'll also note that I've found that MIM guns are much easier to tune for a superb trigger feel than the older forged parts because no additional fitting is needed and the MIM components incorporate features that have to be added to forged parts for an action tuning.
However, S&W was a bit late to the MIM game and they took the time to work with their material suppliers and their process Engineers to make sure they "got it right". I've seen one single posting about an MIM part failing and that was a hammer spur that shear off after many thousands of dry fire cycles without the use of snap caps to cushion the fall of the hammer. Note, just ONE SINGLE FAILURE in two years on a very active forum and it was most likely the result of what many would consider abuse, including the person who posted about that broken hammer spur.
I'll also point out that about 1 1/2 to 2 years ago a member who knew one of the S&W engineers involved in the MIM implementation described the testing that S&W subjected the parts to before making the change from forged to MIM. Basically, they ran MIM and Forged parts in a parallel test that cycled these parts for many many cycles, my memory has the total cycle count being in the millions but I aint got the best memory, it could have been in the 100K range. After all these cycles the MIM and Forged parts were then checked and compared microscopically. The result was that the MIM parts showed LESS wear than the forged and no MIM parts failed during the testing. I suspect that 100 years from now collectors will prefer MIM guns over any other type because they'll stand up better than the forged parts.
As for why, it's pretty simple. MIM allows the material to be fully Engineered for function and structure down to microscopic levels, meaning it's a FULLY Engineered product. Unfortunately, Forged steels can't be fully engineered down to microscopic levels, to some extent "Pot Luck" is in play. BTW, I've had personal experience with that Pot Luck, you should see what happens with you try and drill and tap a hole in a piece of forged steel that has a chunk of tungsten carbide imbedded in it, end result is that nearly finished workpiece goes in the scrap hopper and you start over.
Bottomline, MIM from Smith & Wesson is MIM that has been done correctly. This means that it's as strong and probably stronger than forged steel and contains wear resistant particles in it's engineered matrix that will allow it to last longer than forged parts. IMO, MIM is Win-Win for all concerned, we get a longer lasting gun and S&W no longer has to individually fit each hammer to it's mating trigger. I'll also note that I've found that MIM guns are much easier to tune for a superb trigger feel than the older forged parts because no additional fitting is needed and the MIM components incorporate features that have to be added to forged parts for an action tuning.
Wrong. MIM is superior to standard forging for small parts.
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dla:
Not that I am purposely trying to start a pi**ing match here, but that statement you just made about MIM parts being stronger or better than forged parts goes against everything I have ever learned, heard or read about metallurgy. Now admittedly, I am not a metallurgist, but if you could back up that statement with some real facts I would surely like to read it. Thanks in advance.
Chief38
Not that I am purposely trying to start a pi**ing match here, but that statement you just made about MIM parts being stronger or better than forged parts goes against everything I have ever learned, heard or read about metallurgy. Now admittedly, I am not a metallurgist, but if you could back up that statement with some real facts I would surely like to read it. Thanks in advance.
Chief38
scooter123
Member
Chief, MIM or Powdered Metal metalurgy has a rather long history of development and with proper selection of base material and proper technique, today it can produce parts that are both stronger and more wear resistant than forged steel. That is a fact and I happen to be a Mechanical Engineer who has worked in the Automotive industry since 1982.
At one point Chevy was using PM connecting rods for their premium engine offering in the Corvette Z06, with the Z07 they are now using Titanium because of the weight reduction offered. However, those PM steel rods were actually STRONGER than the prior Gold Standard, the forged Pink rods that so many hot rodders and drag racers sought out for full effort small block race engines.
Now, I don't know if what S&W is using is actually stronger than the forged parts, I don't have the contacts at S&W engineering that I did at GM. However, one thing is VERY evident, that is that whatever they are using is more than "good enough". As evidence of that I'll just point out the complete lack of any reports of these parts failing in normal use. If there were problems with this process I have no doubt that we would have seen endless complaints about pre-mature failure and that has NOT happened.
At one point Chevy was using PM connecting rods for their premium engine offering in the Corvette Z06, with the Z07 they are now using Titanium because of the weight reduction offered. However, those PM steel rods were actually STRONGER than the prior Gold Standard, the forged Pink rods that so many hot rodders and drag racers sought out for full effort small block race engines.
Now, I don't know if what S&W is using is actually stronger than the forged parts, I don't have the contacts at S&W engineering that I did at GM. However, one thing is VERY evident, that is that whatever they are using is more than "good enough". As evidence of that I'll just point out the complete lack of any reports of these parts failing in normal use. If there were problems with this process I have no doubt that we would have seen endless complaints about pre-mature failure and that has NOT happened.
trulyapostolic
Member
The problem with MIM parts is they are cast. You can end up with air pockets and inconsistencies in density. That's why gunsmiths won't use MIM parts, it's to difficult to get perfect finished surfaces (sears, hammers, etc...). Forged parts are machined from billet steel which is homogenous and very rarely would you find a void if ever.
I, like someone else already wrote, believe MIM parts were introduced for cost cutting purposes. If S&W didn't believe the benefit of forged parts they probably wouldn't have produced a Pro Series.
I, like someone else already wrote, believe MIM parts were introduced for cost cutting purposes. If S&W didn't believe the benefit of forged parts they probably wouldn't have produced a Pro Series.
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