MIM Parts

[AR-G23]

I have seen several comments about MIM parts (all negative, if I remeber correctly). What is the problem with MIM parts? Do they break easily, wear out quickly? I did a forum search but I never found a discussion about why (or if) they are really bad? Thanks.

[Carlitos]

Nearly every gun under $1000 uses them and the parts CAN be made properly.

As for Kimber's MIM process, I have seen a lot of broken Kimber brand MIM parts come back, including slide stops and thumb safetys.

I'd suggest a Springfield, S&W, Sig, Dan Wesson, or STI. All much better than a kimber with defective parts.

[Mail Clerk]

Originally posted by AR-G23
I have seen several comments about MIM parts (all negative, if I remeber correctly). What is the problem with MIM parts? Do they break easily, wear out quickly? I did a forum search but I never found a discussion about why (or if) they are really bad? Thanks.

AR-G23,

From what I was told these parts are molded powder that been hardened on the surface only. The insides I heard will crumble of anyone tries to do trigger jobs on them wether it's a revolver or pistol. These parts are cheaper to make and can be made in any form the mold is. With constant usage these parts wear faster than the old fashion way of manufacturing parts.

Mail Clerk

[Jeff S.]

I believe that a properly fitted part is more important than the material of the given part. However, with that said, I'm having a 1911 built and I've specifically avoided MIM parts.

[AR-G23]

Originally posted by Mail Clerk
AR-G23,

From what I was told these parts are molded powder that been hardened on the surface only. The insides I heard will crumble of anyone tries to do trigger jobs on them wether it's a revolver or pistol. These parts are cheaper to make and can be made in any form the mold is. With constant usage these parts wear faster than the old fashion way of manufacturing parts.

Mail Clerk

Is the part about the surface hardening only correct? I worked for an automotive parts manufacturer that made timing gears for GM, Ford, Toyota, etc using a process they called "powdered metal". The powdered metal was formed into a gear in a mold under high pressure from a press. The gear was then run thru an oven to harden. Before going into the oven the gear would crumble if you dropped it, but came out of the oven hard enough for the automotive applications. Is a MIM part similar? If the MIM process is the same, then I would think the parts would be pretty strong, but then again I thought Santa Claus and the Easter Bunny were real until someone told me otherwise.

[One Ragged Hole]

MIM is basically "Sintered Metal" They make connecting rods using the method. It all depends on the process and the care of the manufacturer how good the parts really are. Totally forget about there being "Powder" in the inside of MIM parts;g The part might be surface hardended, but it's all solid.
O-R-H

[freepatriot]

Originally posted by One Ragged Hole
Totally forget about there being "Powder" in the inside of MIM parts;g The part might be surface hardended, but it's all solid.
O-R-H


Keerect.


No worries about still-powdered metal. It all melts together under pressure.


The worry that some have is that there are bubbles in the cooled steel.

Maybe. Mebbe not. I am not overly worried about MIM parts.

[Drjones]

Originally posted by AR-G23
I have seen several comments about MIM parts (all negative, if I remeber correctly). What is the problem with MIM parts? Do they break easily, wear out quickly? I did a forum search but I never found a discussion about why (or if) they are really bad? Thanks.



Never found a discussion about MIM??? You clearly don't know how to use the search function!!!

www.1911forum.com has sooooooooo many threads on this topic too....

Anyhow, it is all basically internet hype.

There are many, many thousands of guns out there with MIM parts, and all of them work just fine.

If you have the choice, you should choose parts machined from bar stock or other high quality parts.

If you have the money to replace parts on your 1911, go for it, though it really isn't necessary.

MIM parts will serve just fine.

[freepatriot]

MIM Parts:

<ul>
Started WWI when they helped assasinate Archduke Ferdinand.
Cause cancer in laboratory animals
Are responsible for the heartbreak of psoriasis
Killed Elvis Presley (on the toilet, no less)
Poisoned Marylin Monroe and killed JFK
Raped Nanking
Shot JR
Caused Hurricane Karina & blew up the levees
Got M*A*S*H* cancelled
Got Dan Rather fired
Caused the Hindenburg fire
</ul>

...and other assorted world tragedies.

[Critter]

Originally posted by scottauld
MIM Parts:

<ul>
Started WWI when they helped assasinate Archduke Ferdinand.
Cause cancer in laboratory animals
Are responsible for the heartbreak of psoriasis
Killed Elvis Presley (on the toilet, no less)
Poisoned Marylin Monroe and killed JFK
Raped Nanking
Shot JR
Caused Hurricane Karina & blew up the levees
Got M*A*S*H* cancelled
Got Dan Rather fired
Caused the Hindenburg fire
</ul>

...and other assorted world tragedies.

I call BS on this, JR never really got shot, I've got Nick at Night and can prove it.

[Fred]

^c ^c ;f

[freepatriot]

<---Busted by Critter.




Critter forgot more about 1911 than I ever knew. ;f;f;f


#wav

[DAVE RICHARDS]

This seems to be the low down on MIM parts from my research. If, that is if, they are made properly they usually work just fine. Evidently some companies are more thorough in their manufacturing processes and quality control than others.

[horge]

Oiginally posted by Mail Clerk
From what I was told these parts are molded powder that been hardened on the surface only. The insides I heard will crumble of anyone tries to do trigger jobs on them wether it's a revolver or pistol.
Hi, Mail Clerk. :)
The metal powder grains sinter together
throughout the thickness of the part, not just at the surface.

Originally posted by AR-G23
Is the part about the surface hardening only correct? I worked for an automotive parts manufacturer that made timing gears for GM, Ford, Toyota, etc using a process they called "powdered metal". The powdered metal was formed into a gear in a mold under high pressure from a press. The gear was then run thru an oven to harden. Before going into the oven the gear would crumble if you dropped it, but came out of the oven hard enough for the automotive applications. Is a MIM part similar?
Hello, AR-G23! :)
Very close. 'Green' castings of metal powder mixed with
a polymer glue/binder are made, cold, in latex molds. These castings
are then popped out and sent on trays to a sintering furnace. The
polymer binder that holds the part-shape together gradually burns off
(the part loses some volume as a result), but the metal grains
remaining stick together under heat: they never cross over into
'melting', and so do not lose the intended part-shape.

Originally posted by scottauld
No worries about still-powdered metal. It all melts together under pressure. The worry that some have is that there are bubbles in the cooled steel.
Hi, scottauld :)
It technically doesn't 'melt' together, otherwise the unsupported part
would collapse into a useless puddle in the furnace. Sintering is
getting metal bits hot enough to get tack-sticky without really melting
them down. The metal bits then stick to one another. Unlike hot casting,
which truly reduces metal to fluid state, MIM doesn't require
moulds while in the furnace.

While 'bubbles' cannot occur in MIM (because the metal never goes fluid),
something similar can occur as a fluke: improperly sifted/mixed
metal-and-polymer can lead to polymer clumps --when those clumps
burn off, they can leave small voids where they were.


----
Using automotive parts as a real world example of MIM strength is misleading.
Provided a MIM part's dimensions were designed with MIM in mind
(meaning, a bit thcker than otherwise), no problem ---indeed, power tools
and automotive parts are made via MIM.


The problem is that some parts that were designed with forged or
properly-cast steel in mind, are now being made via MIM without a
corresponding increase in sectional thickness to compensate.
Worse still when some complex shapes are made via making two MIM
halves, and then weakly re-sintering those two together after
application of a metal-polymer slurry.

Unless a gun was actually designed with MIM in mind, I'd rather not
see MIM in it. Gun manufacturers have tried to skirt the danger,
using MIM for low stress parts... but personally, even for those
apps, I'd not want any MIM in a 1911 --not without a mild redesign to
thicken the MIM parts as necessary, and if at all feasible.



h.

[SAWBONES]

Yes, MIM parts can be fine.
Trouble is, you'll never know unless and until one breaks.
And some DO break, suddenly and unpredictably.

I'll take billet or forged parts if I can get 'em, cast if I can't, and no MIM at all, just to be as sure as I can that my gun will work!

YMMV, but when you've had a MIM part break like I have (slidestop), you'll change your mind.

[DAVE RICHARDS]

The two most common MIM parts breakages I've seen on 1911's have been the thumb safties and the slide stops. Usually the thumb safties break pretty fast. An MIM slide stop being an area under allot of stress would be a matter of concearn to me. I'd get (and have gotten) one of the Wilson or Ed Brown bar stock slide stops and put that in my gun(s). The MIM part may never fail but on such an important high stress part I'd rather have the solid steel. Just for piece of mind.

[Drjones]

It is worth pointing out that "high quality" parts made of bar stock or whatever can and will break as well as MIM parts.