Whats mim mean?

BigBill · Nov 21, 2014

I read where a well known gun Smith refuses to work on certain S&W revolvers because of the min cast frames? I think it's a "6" in the model number. (K frame)

Does the new n frame have a casted frame too?

murphydog · Nov 21, 2014

MIM = metal injection molding, currently used to produce revolver hammers and triggers (and I read somewhere here J frame barrels also).

All steel S & W revolver frames are forged, and I think the alloy ones too.

sac-gunslinger · Nov 21, 2014

Metal Injection Molding. It is a method that adopts certain techniques from the plastic and composite injection world and adapts them to metal structures. Starts with powdered metal mixed with a resin, the part is injected in a mold then heated to a very high temp in something akin to an autoclave. The resin "evaporates" and the metals shrink to a very precise size that can be further machined where needed. (This is strictly the $.01 description of the process). The process comes from the aerospace industry where tolerances are far tighter than anyone in the firearms industry ever thought about using.

MIM is not popular with many because it sort of sounds like injection molding, not anywhere near as classy as forging and machining.

Kernel Crittenden · Nov 21, 2014

A leading number "6" in a S&W model number usually indicates stainless steel. For example: the M629 is the stainless version of the blue N-frame M29. The M686 is a stainless version of a L-frame M586. The M638 is the stainless version of the J-frame M38. The M64 is a stainless version of the famous K-frame M10. The M610 is a stainless 10mm N-frame (and is not based on the M10 -- the system isn't perfect).

DFrame · Nov 21, 2014

sac-gunslinger said:
Metal Injection Molding. It is a method that adopts certain techniques from the plastic and composite injection world and adapts them to metal structures. Starts with powdered metal mixed with a resin, the part is injected in a mold then heated to a very high temp in something akin to an autoclave. The resin "evaporates" and the metals shrink to a very precise size that can be further machined where needed. (This is strictly the $.01 description of the process). The process comes from the aerospace industry where tolerances are far tighter than anyone in the firearms industry ever thought about using.

MIM is not popular with many because it sort of sounds like injection molding, not anywhere near as classy as forging and machining.

Excellent explaination and Assessment. Mim parts are easier to manufacture at extreme tolerances but some people still refuse to accept it.

mtrvl · Nov 21, 2014

My question is: How do MIM frames compare in strength to forged frames???

Big Cholla · Nov 21, 2014

mtrvl said:
My question is: How do MIM frames compare in strength to forged frames???

IMHO, as a retired pistolsmith, the mim parts are as good functionally as forged/milled parts and sometimes are better. The hardness can also be greater where necessary. Other than 'classic' looks, IMHO, the handguns with mim parts are as good as those without and sometimes are better. But, now ask me about 'plastic' parts. I recently acquired a S&W M 351PD. Of course I had to look inside it. Much to my dismay the spring cup on the mainspring guide is of plastic. :-( ! I found a steel one in my parts drawer and changed it out. Ugh! A plastic part with a hammer spring bearing against it. S&W, what were you thinking? ......... Big Cholla

Big Cholla · Nov 21, 2014

Misconception?

mtrvl said:
My question is: How do MIM frames compare in strength to forged frames???

Heavens knows I am no S&W expert and I do not try to keep up with the latest coming out of Springfield, but IMHO there are no frames for S&W handguns being made from MIMs. Undoubtedly S&W research dept. has already been experimenting with that concept but none has made the market. Other manufacturers might be using the MIM process for their 'frames'. When you see the reference 'MIM frame' in conjunction with S&W, I'm sure that just means a standard forged and milled steel frame that has been fitted with some MIM internal parts. ....... Big Cholla

DonD · Nov 21, 2014

mtrvl said:
My question is: How do MIM frames compare in strength to forged frames???

Since S&W doesn’t use MIM frames and I’m not aware of anyone who does, this is a question w/o an answer. Don

DonD · Nov 21, 2014

For the OP with over 5000 posts, I’d have thought you’d be more conversant with this issue which has been debated and discussed to death.

MIM parts are strong, precise and economical. They’re here to say despite the dislike of the old is better school. Don

saemetric · Nov 21, 2014

[QUOTE But, now ask me about 'plastic' parts. I recently acquired a S&W M 351PD. Of course I had to look inside it. Much to my dismay the spring cup on the mainspring guide is of plastic. :-( ! I found a steel one in my parts drawer and changed it out. Ugh! A plastic part with a hammer spring bearing against it. S&W, what were you thinking? ......... Big Cholla[/QUOTE]

Did the same on my 43C for the same reason.

Pisgah · Nov 21, 2014

BigBill said:
I read where a well known gun Smith refuses to work on certain S&W revolvers because of the min cast frames? I think it's a "6" in the model number. (K frame)

Does the new n frame have a casted frame too?

If he thinks they have MIM frames, he may be well known but he is not at all knowledgeable...

BigBill · Nov 21, 2014

Ok here's the post about the min castings.

www.clementscustomguns.com/smithwessonrevolvers.html

regalsc · Nov 21, 2014

If the plastic cup is changed out for a metal one on a revolver with a lifetime warranty has doing so now voided the warranty?

BigBill · Nov 21, 2014

DonD said:
For the OP with over 5000 posts, I’d have thought you’d be more conversant with this issue which has been debated and discussed to death.

MIM parts are strong, precise and economical. They’re here to say despite the dislike of the old is better school. Don

I'm sorry I don't know everything. The one person who did was crucified. If I don't fully understand something I ask. There are many different processes in castings.

Macinaw · Nov 21, 2014

Kernel Crittenden said:
A leading number "6" in a S&W model number usually indicates stainless steel. For example: the M629 is the stainless version of the blue N-frame M29. The M686 is a stainless version of a L-frame M586. The M638 is the stainless version of the J-frame M38. The M64 is a stainless version of the famous K-frame M10. The M610 is a stainless 10mm N-frame (and is not based on the M10 -- the system isn't perfect).

Did you mean this to be for a different thread?

Hapworth · Nov 21, 2014

Macinaw said:
Did you mean this to be for a different thread?

It belongs in this thread; KC was saying it's unlikely a MIM frame would have a "6" designation -- per the original post -- because "6" denotes stainless steel.

Hapworth · Nov 21, 2014

DonD said:
For the OP with over 5000 posts, I’d have thought you’d be more conversant with this issue which has been debated and discussed to death.

MIM parts are strong, precise and economical. They’re here to say despite the dislike of the old is better school. Don

If you're going to be a scold, you might want to make sure you've read and understood the OP first -- he asked if S&W was making MIM frames; he did not rehash the MIM debate.

Macinaw · Nov 21, 2014

Hapworth said:
It belongs in this thread; KC was saying it's unlikely a MIM frame would have a "6" designation -- per the original post -- because "6" denotes stainless steel.

Thanks for the clarification.

Kernel Crittenden · Nov 21, 2014

Macinaw said:
Did you mean this to be for a different thread?

Read the OP. I took it to mean he was asking if the number "6" had any significance in regards to the frame's metallurgy. If you study S&W model numbers you learn the number six does have a very specific meaning, which I attempted to explain.

Whats mim mean?

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