huntsman
Member
does the 625JM or model29 classic use MIM?
MIM parts?
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Lucky Derby
Member
All current production S&W revolvers use MIM parts.
OP
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huntsman
Member
thanks all
InkEd
Member
They are still excellent guns.
To save some bandwidth : MIM parts are {insert your favorite percentage} the strength of forged parts. Aircraft turbine blades and race car pistons are made of MIM. When MIM parts fail its usually early on.....blah blah blah ect.
BUT - forged parts are 100% the strength of forged parts.
BUT - forged parts are 100% the strength of forged parts.
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huntsman
Member
really? twenty years ago (when I last worked in the industry) they were forged from titanium, inconel and monel
Early MIM parts had problems. It was a relatively new technique for making gun parts; the companies who did MIM were not familiar with gun making, and the gun makers were too quick to jump to MIM. Today, I believe that MIM parts are just as good as forged parts and much less expensive.*
I remember when folks learned that Ruger used castings; many people were horrified, remembering the cheap cast iron guns that flooded the country in the 1920's, and blew up by the thousands. Today, Ruger still uses castings, and is respected as one of the top gun makers of the world. I also remember when the German P.38 was denounced as a "cheap, stamped out piece of crap", and the Ruger Standard Model was said to be made out of old beer cans.
*Much has been made of S&W going to MIM for hammers and triggers instead of "forged parts." But those S&W parts had not been forged for decades; they were blanked out of thick steel plate and machined. With MIM, no punching, machining, drilling, milling or cutting is needed.
Jim
I remember when folks learned that Ruger used castings; many people were horrified, remembering the cheap cast iron guns that flooded the country in the 1920's, and blew up by the thousands. Today, Ruger still uses castings, and is respected as one of the top gun makers of the world. I also remember when the German P.38 was denounced as a "cheap, stamped out piece of crap", and the Ruger Standard Model was said to be made out of old beer cans.
*Much has been made of S&W going to MIM for hammers and triggers instead of "forged parts." But those S&W parts had not been forged for decades; they were blanked out of thick steel plate and machined. With MIM, no punching, machining, drilling, milling or cutting is needed.
Jim
Sunray
Member
"...Aircraft turbine blades..." Nope. ECM'd out of blocks of TI. I hated that job.
Like Jim says, there's nothing wrong with MIM parts.
Like Jim says, there's nothing wrong with MIM parts.
Guillermo
member
with good reason
Sheepdog1968
Member
I sat through a 1911 class by John Jardine and he must have spent 20+ minutes talking about MIM parts. They can be as good as other parts mfg'd by different methods; it all depends on how it is manufactured. He went into great detail and I quickly got lost.
"Some gunsmiths ... won't work on them..." "With good reason."
I would like to hear the reason other than that MIM parts are both very hard and smooth without the machine tool marks common to the old parts. So the "file and stone" guys have nothing to do and can't collect big bucks for an action job any more.
Jim
I would like to hear the reason other than that MIM parts are both very hard and smooth without the machine tool marks common to the old parts. So the "file and stone" guys have nothing to do and can't collect big bucks for an action job any more.
Jim
MiM is just another process. It may be the right process, or the wrong process, depends on the use. If it breaks, some engineer was a dope. I could argue the parts milled from solid bar stock could be crap, because they can be in the wrong application, with sharp corners that raise stress. Forgings are great, but machine a sharp corner into a stress area and they can be crap also. Stampings are cheap crap, but there are AK's out there for 50 years made from stampings - the advantage being it's very hard to put a sharp corner into a stamping, it doesn't cut the material grain, and the process of stamping work hardens the metal.
So the right process for the right application works. Preaching something or other is the only way to make a gun has been BS since about 1650. We can make whatever we want, in any manner we want, how much money you want to spend to do it?
So the right process for the right application works. Preaching something or other is the only way to make a gun has been BS since about 1650. We can make whatever we want, in any manner we want, how much money you want to spend to do it?
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1911Tuner
Moderator Emeritus
Some MIM is good. It can be excellent, in fact. Some...not so good. It depends on the material...both metal and binder...and adherence to proper sintering.
I removed an MIM sear from a Colt 01991 when the owner wanted to swap out the bad, old MIM for machined steel.
I decided to see what the deal was, so I conducted a scientific test on the takeout sear.
I laid it on an anvil...cupped side down...and whacked it a few times with a hammer.
It didn't shatter.
Curious, I installed it in a gun. It functioned just fine, although the trigger was a bit rough.
What are we to make of this...other than the fact that Colt has apparently found a vendor that makes very good MIM?
I removed an MIM sear from a Colt 01991 when the owner wanted to swap out the bad, old MIM for machined steel.
I decided to see what the deal was, so I conducted a scientific test on the takeout sear.
I laid it on an anvil...cupped side down...and whacked it a few times with a hammer.
It didn't shatter.
Curious, I installed it in a gun. It functioned just fine, although the trigger was a bit rough.
What are we to make of this...other than the fact that Colt has apparently found a vendor that makes very good MIM?
Guillermo
member
there are several knocks against MIM parts for many of the applications within a revolver. The larger parts, such as John's MIM sear are unlikely to fail. Generally it is the smaller parts (or tight tapers or sharp edges) that have issues. They COULD make MIM parts better than forged...but that is another story.
To answer your question, the main reason that many "smiths won't work on them is that they can't be polished effectively. They do "burnish" which is why dry firing the heck out of an MIM gun is a good thing to do. (works the trigger finger too).
This is why when Jerry Miculek wanted to improve the action on the special edition revolver that bore his name, they flash chrome the MIM hammer. Of course MIM does not play well with other metals and does not hold the chrome. In many cases the chrome comes off. (you can imagine what lovely trigger action it has then
)
So in a nutshell...many gunsmiths do not work on them because they can't polish up the working surfaces to improve the action. A disappointed client is bad for business, so they punt.
To answer your question, the main reason that many "smiths won't work on them is that they can't be polished effectively. They do "burnish" which is why dry firing the heck out of an MIM gun is a good thing to do. (works the trigger finger too
). This is why when Jerry Miculek wanted to improve the action on the special edition revolver that bore his name, they flash chrome the MIM hammer. Of course MIM does not play well with other metals and does not hold the chrome. In many cases the chrome comes off. (you can imagine what lovely trigger action it has then
)So in a nutshell...many gunsmiths do not work on them because they can't polish up the working surfaces to improve the action. A disappointed client is bad for business, so they punt.
"...the main reason that many "smiths won't work on them is that they can't be polished effectively..."
Well, that was my point. Done right, MIM parts don't need polishing. For an example, when a trigger is made by other methods, it is milled to final shape and the cutters create tiny cross-wise grooves in the critical areas. Those cuts, under magnification, look like a plowed field, and if deep enough cause a trigger to feel "creepy" or "rough." The gunsmith uses a stone to polish and smooth out the grooves and remove the trigger roughness.
But MIM parts are not machined and do not have those tool marks; the critical parts of the trigger (and other parts) are made smooth and polishing them has no effect. Factory technology has caught up with the "action job."
Not the only case, of course; cars once required a "tuneup" (points, plugs, rotor change and timing adjustment) every 5000 miles. When was the last time your new car needed that work done?
Jim
Well, that was my point. Done right, MIM parts don't need polishing. For an example, when a trigger is made by other methods, it is milled to final shape and the cutters create tiny cross-wise grooves in the critical areas. Those cuts, under magnification, look like a plowed field, and if deep enough cause a trigger to feel "creepy" or "rough." The gunsmith uses a stone to polish and smooth out the grooves and remove the trigger roughness.
But MIM parts are not machined and do not have those tool marks; the critical parts of the trigger (and other parts) are made smooth and polishing them has no effect. Factory technology has caught up with the "action job."
Not the only case, of course; cars once required a "tuneup" (points, plugs, rotor change and timing adjustment) every 5000 miles. When was the last time your new car needed that work done?
Jim
JDBoardman
Member
Turbine blades are neither MIM nor are they machined. For the most part, they are investment castings, either directionally solidified, equiaxial solidified or single crystal. There is no other way to create the complex labyrinth of cooling air passages inside the blade other than casting. Investment casting (also known as lost wax casting) is the same process Ruger uses for its firearms.
MIM (Metal Injection Molding) involves pumping a slurry of fine metal powder with binder into a mold, allowing the slurry to cure ("green" part). The part is then sintered at temperature to burn out the binder and fuse the powder particles into a solid mass. The end result is a near net shape part that requires little if any finish machining. The basic process is very similar to powder metallurgy, except it substitutes a mold and injection pump for the high force press used to form the "green" parts when pressing powder. As has been said previously, if the part is designed and manufactured properly, it is as good as a machined forging at lower cost. If not properly designed or correctly made, it is junk.
An additional process can be used on MIM, sintered and cast parts to increase the density of the finished part, reduce or eliminate internal voids or porosity and produce an external skin more nearly resembling a machined bar stock or forging. In Hot Isostatic Pressing (HIP) the part is put in an inert atmosphere furnace, heated up to very close to the melting point while raising the pressure to 15,000 to 25,000 pounds per inch squared. This pressure surrounding the part squeezes it, collapsing internal voids and sintering the particles into a structure virtually as dense as a forging. But this improvement in density comes at a cost - it costs both time and money to perform this process. Again, it is the responsibility of the design engineer to determine if this is necessary, or if some other part fabrication process will give the desired results at less cost, shorter time,or better quality (or any combination of these factors).
MIM parts can be, and generally are, every bit as functional as parts made in more conventional methods. They cost less to make, and are more uniform in dimensions, but the surface finish is not quite as nice. The older forged, machined and case colored fire control parts in a S&W revolver are admittedly better looking than the newer generation MIM parts, but the new parts are as functional and just as strong as the older parts. The cost savings in machining labor is reflected in the final cost of the revolver - in today's competitive environment, the manufacturer has to go for every cost savings possible without adversly affecting the end quality of the product.
MIM (Metal Injection Molding) involves pumping a slurry of fine metal powder with binder into a mold, allowing the slurry to cure ("green" part). The part is then sintered at temperature to burn out the binder and fuse the powder particles into a solid mass. The end result is a near net shape part that requires little if any finish machining. The basic process is very similar to powder metallurgy, except it substitutes a mold and injection pump for the high force press used to form the "green" parts when pressing powder. As has been said previously, if the part is designed and manufactured properly, it is as good as a machined forging at lower cost. If not properly designed or correctly made, it is junk.
An additional process can be used on MIM, sintered and cast parts to increase the density of the finished part, reduce or eliminate internal voids or porosity and produce an external skin more nearly resembling a machined bar stock or forging. In Hot Isostatic Pressing (HIP) the part is put in an inert atmosphere furnace, heated up to very close to the melting point while raising the pressure to 15,000 to 25,000 pounds per inch squared. This pressure surrounding the part squeezes it, collapsing internal voids and sintering the particles into a structure virtually as dense as a forging. But this improvement in density comes at a cost - it costs both time and money to perform this process. Again, it is the responsibility of the design engineer to determine if this is necessary, or if some other part fabrication process will give the desired results at less cost, shorter time,or better quality (or any combination of these factors).
MIM parts can be, and generally are, every bit as functional as parts made in more conventional methods. They cost less to make, and are more uniform in dimensions, but the surface finish is not quite as nice. The older forged, machined and case colored fire control parts in a S&W revolver are admittedly better looking than the newer generation MIM parts, but the new parts are as functional and just as strong as the older parts. The cost savings in machining labor is reflected in the final cost of the revolver - in today's competitive environment, the manufacturer has to go for every cost savings possible without adversly affecting the end quality of the product.
Guillermo
member
Unfortunately MIM parts as Smith manufactures them do need to be smoother. (there is nothing wrong with MIM...it is "Smith way" which is ultra hard, the same density all the way through and constructed of a rough "grain")
Of course they COULD be made to be smoother and stronger than a forged part but it would take a multi step process that would raise costs.
Personally, if I was a suit at S&W, I would have my engineers create some MIM parts with a soft, flexible core covered by an ultra fine grain, ultra hard, MIM veneer.
I would sell the parts to 'Smiths at very high prices and put them in ultra high end editions.
If they did that they would produce (perhaps) the best gun parts ever made.
Of course they COULD be made to be smoother and stronger than a forged part but it would take a multi step process that would raise costs.
Personally, if I was a suit at S&W, I would have my engineers create some MIM parts with a soft, flexible core covered by an ultra fine grain, ultra hard, MIM veneer.
I would sell the parts to 'Smiths at very high prices and put them in ultra high end editions.
If they did that they would produce (perhaps) the best gun parts ever made.
Guillermo
member
actually they cost more to make...but they are considered finished when they pop out of the mold. Forged parts cost less but require more processing, thus raising their costs.
this is probably what you meant but I just wanted to clarify
1911Tuner
Moderator Emeritus
Additionally...A single mould will drop parts that are exactly the same for thousands of parts.
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huntsman
Member
not at TRW they were forged, had a 3 story press (another 2 stories in the floor) to do the first stage fans (CF6) in the big GE engine. parts weighed close to 90lbs when they came out of the press.
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