MIM parts in firearms how can we tell?

[pat701]

I don't know if i posted this question in the correct forum but here goes. Is there a way for a average person that isn't a Tool and Die maker to tell with a simple field strip if a pistol he wants to buy has MIM parts? :confused:

[RD62]

This question would probably go better in one of the handgun sub-forums versus the AR Technical one.

That said ALOT of handguns now use MIM components so you'd probably be better of narrowing down what model you are interested in and going from there.

[crossgun]

Usually you will see a "parting line" on the part. This would be the hairline or edge that goes around the entire part usually on the width. It might be in the middle or very close to either the top or bottom surface. Somewhere on the parting line you should also notice an area where there is a"gate". This is the place that the material is pushed into the mold and then cut off from the part after molded.

One side of the part should also have some evidence of some small pin marks usually located in cavities in the part or around holes. These are from the "ejector pins" in the mold which push it out of the mold once it is molded.

Think of MIM parts just like plastic parts with all the tell tale signs. MIM parts are pretty easy to spot.

[BufordTJustice]

Usually you will see a "parting line" on the part. This would be the hairline or edge that goes around the entire part usually on the width. It might be in the middle or very close to either the top or bottom surface. Somewhere on the parting line you should also notice an area where there is a"gate". This is the place that the material is pushed into the mold and then cut off from the part after molded.

One side of the part should also have some evidence of some small pin marks usually located in cavities in the part or around holes. These are from the "ejector pins" in the mold which push it out of the mold once it is molded.

Think of MIM parts just like plastic parts with all the tell tale signs. MIM parts are pretty easy to spot.

BIG +1

I have nothing to add. Great explanation.

[Dave_M]

MIM parts, in and of themselves, are not, 'deal-breakers' by any means. Shit, MIM is used in the aerospace industry...

[BufordTJustice]

Dave, I agree. As long as the part in question was designed from the git-go to be MIM and that is an initial consideration of the design of the machine, it's not an issue. Issues seem to arise most often when somebody started with a costly machined part or forged part within a mechanism and then transitioned to an MIM'd part at a later point, without altering the geometry of the part or incorporating post-mold processes to remove the mold marks or any other burrs (and possibly incorporate MPI to detect voids).

I have no prob with it being a used when that use was pursuant to a choice made by an engineer. I DO have an issue when it is an after-the-fact substitution for a machined/forged part made by a bean counter purely to save on production costs. I'm not gonna say the G-word (that rhymes with Glock)....but....oh damn.....I'm sorry.

[cz7]

MIM parts, in and of themselves, are not, 'deal-breakers' by any means. Shit, MIM is used in the aerospace industry...if it's is done right it works but short cuts like low temps cold molds wrong pressure etc its crap !!!junk plus inspection needs to be done for Q/C .....more costs etc

[crossgun]

The secret is not at all in the molding. It's in the debinding and sintering. If you understand the process and work with the MIM house up front on the design then you can achieve some outstanding results.

[Palmguy]

MIM parts, in and of themselves, are not, 'deal-breakers' by any means. Shit, MIM is used in the aerospace industry...

Correct. If the intention of the OP is to use the presence of MIM parts as a litmus test for whether or not any given firearm is worth buying, they are looking at it the wrong way in my opinion. The big picture should be top priority with a design perspective, not a process perspective. Machined steel is capable of failing if not designed properly and MIM parts are capable of being reliable if designed properly.

[JSantoro]

I don't know if i posted this question in the correct forum
Metaphorically, you decided to take a dump in one of the cups at the Mad Tea Party instead of simply asking one of the Disneyland security guards where the bathrooms are located.

Closed, until you get a chance to tell me enough info for me to know which HANDGUN subforum (of the three we have...) in which to put this PISTOL question.