MIM parts

[anchors]

What are MIM parts and why are they disliked so much?

 

[anchors]

What are MIM parts and why are they disliked so much?

 

[gunguy56]

I'll give you my experience with MIM-parts. As you may know, MIM parts are created by metal powder being mixed with an epoxy and formed in a mold under pressure so that the manufacturers don't have to use labor and machine time to make small parts. I bought one of those new Taurus PT1911 autos. Thought it was a good buy considering all the included features on it. Took it to the range, and fired 4 boxes of WWB 230 gn FMJ for a break-in session. No malfunctions, shot good. I was happy. when I got home, I took it apart for a cleaning-when I slid the slide off the frame-the MIM-made ejector fell out. (Evidently the slide had been holding it in place while it was assembled). The front leg of the ejector was broken off, and only the shorter rear leg was holding it to the frame. Since the front leg is in a blind hole, there was no way to tap it out. My dealer sent it back to Taurus. Two months later I had a new pistol. Great warranty-crappy part. I've had about a dozen 1911's over the last 40 years-never had a machined ejector break. Can't afford to stake my life on MIM-type parts...

 

[WR Moore]

MIM stands for Metal Injection Molding. I dunno about epoxy being mixed with metal powder, the process I saw back in the dark ages was molten metal injected under pressure into dies that form the part.

Properly done, you get a part with little or no need for machining, thereby eliminating a substantial cost. Like anything else, if improperly done, you get a defective part.

I do know that trying to drill MIM triggers to install stops was impossible. I had to mill the holes. Was kinda like trying to drill casehardend parts without breaking the case.

I do believe that much of the distaste is caused by it isn't traditional thinking.

 

[animalmother]

I have no problem with MIM parts in non-critical applications. As gunguy56 notes, the MIM extractor was defective in his Taurus 1911. Have heard similar stories about MIM extractors in autoloaders. MIM parts like triggers, thumb safties, and cylinder releases do not seem to be a problem. I have a few S&Ws with MIM parts. Nothing has gone wrong with them yet.

 

[18DAI]

I don't really have anything against MIM. It's simply another cost cutting measure to allow companies to remain competitive in a shrinking market.

I have had two MIM parts break. The first was a thumb safety on a Kimber 1911. The other was a mag catch on a S&W 4516-3. Both pistols were functional after the parts failures.

My preference is for forged parts, I've yet to have one of them fail. FWIW The S&W Performance Center does not use MIM parts, only forged. I have never heard the MIM fans here, adequately explain that away

. Regards 18DAI.

 

[presspics]

I like the MIM parts that S&W makes. They are better finished and provide for a smoother action right out of the box.

 

[gmchenry]

Originally posted by 18DAI:
My preference is for forged parts, I've yet to have one of them fail. FWIW The S&W Performance Center does not use MIM parts, only forged. I have never heard the MIM fans here, adequately explain that away

. Regards 18DAI.

Because they have to justify the significantly higher price tag of a PC product.

The MIM process is not evil in and of itself. I have seen very well made MIM parts and I've seen crap MIM parts. S&W makes very good MIM parts. Some of the worst MIM parts I've ever seen were from Para-Ordnance. Easily broken, mis-shapen, poorly finished, and usually with a thin chrome plating that flakes off.

 

[NCTexan]

I'd be interested to hear perspectives on MIM parts in the firing mechanism... and how effectively they can be tuned, stoned and fitted versus forged parts.

Bottom line... Can you get as good a trigger job done with MIM as forged?

 

[TAC]

There is a good description on MIM here:
http://en.wikipedia.org/wiki/Metal_Injection_Molding

 

[shawn mccarver]

Originally posted by anchors:
What are MIM parts and why are they disliked so much?

Metal injection molded parts are made differently than other parts, and the process allows the parts to be made much more precisely, so that lots of hand fitting is not required.

MIM parts are hated by a fairly noisy minority for mostly emotional reasons, i.e. it has not always been done that way. There are probably threads on this forum discussing issues people have with MIM parts.

Now I realize that some are going to be offended by the earlier characterization, but I have just not seen a significant number of problems with MIM parts to be worried about them.

I do not give MIM parts a second thought. I am old enough to remember when we did not have stainless steel revolvers, when everything was pinned and recessed, etc. People distrusted the change to non-P&R barrels and cylinders and some still do, but in the long run, the revolvers are just as good without those extra steps.

 

[shawn mccarver]

Originally posted by gunguy56:
I'll give you my experience with MIM-parts. As you may know, MIM parts are created by metal powder being mixed with an epoxy and formed in a mold under pressure so that the manufacturers don't have to use labor and machine time to make small parts. I bought one of those new Taurus PT1911 autos. Thought it was a good buy considering all the included features on it. Took it to the range, and fired 4 boxes of WWB 230 gn FMJ for a break-in session. No malfunctions, shot good. I was happy. when I got home, I took it apart for a cleaning-when I slid the slide off the frame-the MIM-made ejector fell out. (Evidently the slide had been holding it in place while it was assembled). The front leg of the ejector was broken off, and only the shorter rear leg was holding it to the frame. Since the front leg is in a blind hole, there was no way to tap it out. My dealer sent it back to Taurus. Two months later I had a new pistol. Great warranty-crappy part. I've had about a dozen 1911's over the last 40 years-never had a machined ejector break. Can't afford to stake my life on MIM-type parts...

In my opinion, buying the Taurus was the mistake here. I have owned plenty and have never had a single one that did not have a failure that would have put me out of a fight. Taurus is junk and NO ONE should every purchase one if the intended use is to protect human life. I would go further and say that Taurus does not stand behind their product either. I have been promised a shipping label twice since January 2008 and am still waiting. The Taurus in question would not fire on its first trip to the range and there is no way it could have made it out the door if it had been test fired. If Taurus test fires, then this one was overlooked.