My E-mail to Kimber and their reply Regarding the MIM parts in my TLE II

[Master Blaster]

Greetings,
Three months ago I bought a new TLE II.
I am considering carrying it on a daily basis as my CCW defense gun.
There is one problem though. I have read about and seen pictures of two of the mim parts in my Kimber that have broken unexpectedly on other people.

Those parts are the firing pin safety, and the slide stop.
I find it hard to trust an MIM part in a high stress application such as this especially when it could cost me my life should the gun refuse to function when I need it most.

How frequently do these parts break, is there some defect in them that causes this to happen? Are there any non mim parts that I can use to replace these parts???

I am really disappointed that after I spend $800 on a handgun that I may not be able to rely on it due to cost cutting measures such as using cheap mim parts where machine barstock would be a more reliable solution.

I look forward to a prompt response.
Sincerely,



Andrew R. Cohen M.B.A.

Their Reply to Me:

From: Devin Antonovich [[email protected]]

METAL INJECTION MOLDING : MIM


MIM: A process in which powdered chrome moly steel is mixed with a polymer carrier, placed into an oversized mold, and sintered. The part shrinks to size in the process, then heat-treated.

The result is intricate parts which are:

- extremely accurate

- more dense than investment cast parts

- 98% of the strength of a forged part

Many of the important internal parts on a Kimber are MIM parts:

Slide Stop

Thumb safety

Grip safety

Disconnector

Sear

Hammer

Strut

Magazine catch


Note: The ONLY Polymer part on the Kimber is the mainspring housing.


Springs: Wolff

Very Informative and responsive to my concerns EH????

 

[meathammer]

Wow! Nice to see they addressed your question.

They could at least admit that failures do/can occur. Maybe give you some kind of solution or say they are looking into the problem.

 

[krept]

they just told you what to replace, right?

seriously, I DOUBT they'll ever issue a "yeah, we screwed up" statement or even an "upgrade" as other situations have been called.

btw, I wonder what some of the unimportant parts are?
cheers

 

[Majic]

There is nothing wrong with the process. It's used quite frequently in many manufactoring applications. The problem comes from lack of quality. Like anything else if the attention is not paid to detail then any machanical device can break.
As the MIM parts is all that Kimber uses now you should expect them to fully stand behind it. To not do so would open the door for lawsuits against them. Just go to the aftermarket for forged steel parts to swap out to get your peace of mind. Just remember any part can break be it forged or cast and considering the number of units Kimber puts out you may never have a problem with your MIM parts.

 

[McNutt]

Is their claim of "98% of the strength of a forged part" incorrect? If it's true then I don't think it should be an issue.

 

[Kruzr]

Is their claim of "98% of the strength of a forged part" incorrect? If it's true then I don't think it should be an issue.

It's correct and when they are, it isn't an issue. Some get by that aren't as strong. From what I've seen, they either break early in life or not at all.

MIM Tutorial (all you want to know)

 

[R.H. Lee]

OK. I have a stupid question. What is the functional difference between Colt, Kimber and Springfield, if they all are production pistols with MIM parts? Why are Colt and Kimber so much more expensive?

 

[7.62FullMetalJacket]

You tell them that you have a concern about 2 MIM parts and they list 6 more for you to worry about.

 

[Grump]

The vast majority of the time, I consider a 2% difference negligible.

- more dense than investment cast parts

That tells me nothing about its strength compared to investment cast parts. Anyone know this?

With what little I know about manufacturing, it seems that the modes of defect/failure o*should* be known and quantifiable..."our precesses result in unservicably defective parts 0.3% of the time", for example. That would also mean that they *should* know how to detect those defects.

So, what I wanna know is: how can the defective parts be detected, and does Kimber do that? Seems like a little x-ray inspection could find internal voids or similar problems that lead to the few spectacular failures we've seen photographed. Kimber needs to let us know why we should trust them to have ALL their MIM parts performing at 98% of the strength of forged parts.

 

[Correia]

Accountant hat on. Some of you guys have never worked in a mass production manufacturing facility have you?

Kimber went with MIM to save money. If they need to X-ray or magnaflux every single part to make sure that it is perfect, that defeats the purpose of going to MIM to save money to begin with. Machine inspections take time and trained operators both of which equal money.

I'm willing to bet they do spot tests, and they probably have some sort of manufacturing engineering quality testers in place, but very rarely does a company have sufficient mark up on a product that every single part can be checked. Some companies do stuff like that, but their products ain't going to be cheap.

They aren't going to tell you what their failure rate is. Every manufactured part in the world has a failure rate of some kind, and I'm willing to bet that if you contacted the manufacturers in those industries they wouldn't tell you what their rate of returns was either. Can you imagine? In whatever profession you were in, how would you respond if a customer contacted you and asked how often you screwed up, and when you answer most of the time you don't screw up, how would you feel when that customer got angry at you?

Plus if you are brand Y, and you flat out admit that 3% of your parts are going to break, brand X (your competitor) is going to flog you in the market with that. Brand Y breaks 3% of the time! Even if brand X breaks 7% of the time, they sure as heck ain't going to admit it in public, and now they are outselling you.

I've seen two MIM parts break in the last three years. Both were thumb safeties on brand new guns in IDPA matches. In that same time I've seen an expensive, top of the line brand new bar stock extractor break as well. Any type of manufactured part can break. If you are really worried about it, the customer service guy gave you a list of parts to replace.

 

[R.H. Lee]

Accountant hat on. Some of you guys have never worked in a mass production manufacturing facility have you?

Any savvy entrepeneur would cut back on the bean counters-they're overhead and don't produce a nickel of revenue

 

[cerberus]

Doing my own MIM parts failure testing

I have three new Kimbers a Custom TLE II Tac Pro II and Ultra Carry II they all have Kimber supplied MIM parts. And so far after about 2700 rounds of 230 gr. Blazer Ammo. all parts are holding up great. If I have any failures I will post them for all to see.

 

[Correia]

Riley, I work for saavy entrepeneurs. Sadly none of them can balance a checkbook to save their lives.

 

[Monkeyleg]

I've posted on this subject before, but will do so again, this time with a question at the end.

I have three Kimbers. One is six years old, has nearly 20,000 rounds through it, and no part has ever broken. The other is five years old, has thousands of rounds through it, and never had a part break until I dropped it and broke the safety (among other things). The new thumb safety broke almost immediately, and I could see the air cavity. The third pistol is eight months old, and doesn't have enough rounds through it to even mention.

From reading other posts on this subject, it would seem that the primary failure of MIM parts is due to air pockets. It would seem to me that this failure would happen sooner rather than later, as it's not so much an issue of the part not being durable, but rather the part having a pronounced defect.

So, the question: is this a correct assumption?

 

[Daniel T]

What is the functional difference between Colt, Kimber and Springfield, if they all are production pistols with MIM parts?

I didn't think that Colt used MIM parts.

 

[Blueduck]

As for the e-mail if you had not figured it out, many companies now use computer programs that try to "guess" your question based on words or phrases then send out a "standard form" e-mail to answer the question they assume you were asking. Sounds like this is what Kimber is using-next step up from voice mail I guess..

More you think about above concept more it sounds like something from a British sitcom

 

[cerberus]

Only chance left

I think it's like GM Ford and Chylsler you have no real chance of geting real answers to your quality questions. The only chance left at Kimber is with the Custom Shop and Denise the shop manager. Sending e-mail to their marketing Dept. is time just wasted.

 

[WonderNine]

I didn't think that Colt used MIM parts.

Colt switched to using a few MIM parts a few years ago. Recently, I believe they stopped using the MIM extractors because of all of the breakage problems they were having. They also use a MIM sear (but the hammer is not MIM) and I believe a MIM magazine release. There's a couple other parts that are MIM that I can't think of right now. I believe the grip safety is cast. The frame and slide are forged. There's a list of MIM parts that Colt uses on 1911 forums.

If forged parts are not any better why do you almost never hear about broken parts on old BHP's.

 

[mete]

Let me put on my metallurgists hat on. Denser than investment casting ? --That's BS. ...98% of the strength of forging ? -- depends on how it's made....To repeat my previous comments on the subject - there are many variables in the MIM process; what alloy is used, how it is heat treated ,how the part is designed ,etc. If everything is done properly ,MIM parts will do the job well.

 

[JohnBT]

"So, the question: is this a correct assumption?"

It seems like all the posts I've seen on the subject over the past 5 years were about new guns with less than a thousand or so rounds through them.

I cannot recall ever seeing a thread about old Kimbers breaking. I bought mine in 1999 and have fired more than 10k rounds. I have replaced some parts, but only because I bought a how-to book.

Everytime a MIM thread breaks out I wonder why we've had gunsmiths for hundreds of years if those old forged steel guns never broke.

John

 

[Old Fuff]

First of all, it is generally agreed that MIM parts are being used for the principal purpose of saving the manufacturer money, not to make a better product.

Then Kimber says: "MIM: A process in which POWDERED CHROME MOLY STEEL IS MIXED WITH A POLYMER (plastic) CARRIER, placed into an oversized mold, and sintered. The part shrinks to size in the process, then (is) heat-treated.â€

Now if you guys want to stake your necks on a combination of powdered metal and plastic that's your business. It is quite possible they work, and work well over the long run.

It is also possible that for various reasons, not the least being a lack of comprehensive quality control, and a propensity to pick the sub-contractor with the lowest bid, that they will break - usually at the most inopportune time.

As for myself, I use guns that are “pre-powdered metal,†and sleep well at night knowing that when mine were built the number crunchers and bean counters weren't in charge.

I may change my mind, but not until the rest of you risk your lives for a long time finding out if I'm right or wrong.

 

[wintermute76]

Kimber went with the lowest (lower at least) bidder on their tooling and it does show. They don't make all bad parts, but enough that it gets noticed.

How many MIM failures have been seen in Smith and Wessons? I know that Smith has some MIM revolver hammers, triggers and some 2" .38 barrels. Also their new SW1911 has MIM slide stop and ejector at least.

Better tooling, better parts.

MIM is a good process, I"ve heard the same 98-99% density and negligible reduction in strength. Cast parts are anywhere from 60% to 80% dense.

 

[Zircon]

Monkeyleg
Senior Member

Registered: Dec 2002
Location:
Posts: 1651

I've posted on this subject before, but will do so again, this time with a question at the end.

I have three Kimbers. One is six years old, has nearly 20,000 rounds through it, and no part has ever broken. The other is five years old, has thousands of rounds through it, and never had a part break until I dropped it and broke the safety (among other things). The new thumb safety broke almost immediately, and I could see the air cavity. The third pistol is eight months old, and doesn't have enough rounds through it to even mention.

From reading other posts on this subject, it would seem that the primary failure of MIM parts is due to air pockets. It would seem to me that this failure would happen sooner rather than later, as it's not so much an issue of the part not being durable, but rather the part having a pronounced defect.

So, the question: is this a correct assumption?


__________________
Dick

The flaws in MIM are typically small voids (air pockets, if you will.) The longevity of the part depends on the size of the flaw. If the voids are very small they will do no practical harm during the lifetime of the part. The larger the voids are, the more deleterious. If they are very large, such that the crossectional area is compromised, then the part can fail the first time it is loaded, because there is insufficient "meat" to carry that load. As the voids get smaller the crossectional area increases to theoretical, however, the voids can serve as nucleating sites for subsequent cracks. With repeated loading the cracks grow out of the voids, and progress across the part. This failure mechanism (under repeated loading) is known as fatigue.

The plastic carrier is only used to keep the metal powder in an arrangement which is the shape of the final part. It is removed during the early part of the heating or sintering process, known as the debinding step. As the metal powder densifies under the heat of sintering the voids are minimized in number density and in size, but they are never eliminated. For all practical purposes, however, if the voids are very small, they will not serve as fatigue crack initiators. This is where proper process controls are required. Controls such as powder size and shape, amount of binder, debinding, sintering temperature and time, sintering atmoshpere controls, etc.

The easiest attribute is to just measure the density of the part. If it meets a certain requirement then it can be presumed good. Certainly radiography would not be appropriate to determine porosity, because of expense, and the fact that the porosity would likely be too fine to image on the radiographs.

One method to assure high density and lack of voids would be to hot isostatically press (HIP) the part. This process is often used on critical aerospace castings to "squeeze" out any remaining porosity from the casting process and to achieve near 100% densification. Of course this costs money, and I doubt if Kimber or anyone else is willing to go to this extra expense.

Oh, regarding density of castings, the number is much higher than 60 to 80%. At those densities any casting could be considered scrap. The numbers are more like up in the very high 90's for a well made casting.

Zirc

 

[7.62FullMetalJacket]

Zircon,

Good explanation and welcome to THR .

MIM is used in many industrial applications to make parts. Each of us must consider the qualities of MIM and the potential for failure. No process is perfect and QA/QC is of the utmost importance. That these failures happen on life-saving instruments is disconcerting.

I am in the same school of thought as Old Fuff. I would prefer to not rely on MIM parts for a carry gun. A race gun or competition gun or even target gun would be acceptable because failure may lead to embarassment, but not likely death.

We are not talking about a weed eater or a drill press; we are talking about a tool that is used in the last line of defense. It needs to go bang each and every time you need it. Until Kimber gets the Quality Control under control, they will not get my money.

 

[Zircon]

7.62,

Thanks for the welcome. No quibble from me. I do have a Kimber, and I replaced the slide stop with a billet steel part, even though the original MIM piece did not fail. I think the stop is one of the more heavily loaded parts based on function and crossectional area.

Parts like the strut, thumb safety and grip safety are relatively lightly loaded and not likely to fail unless there is a gross defect in them. (And, yes, someone will come along and tell me that theirs have failed, but so far mine has not with several thousand rounds through it.) I'd probably have replaced the sear/hammer combo also, but I don't particularly want to screw with what is already a nicely tuned trigger.

I feel compelled to post on the MIM vs. wrought steel issue as there has been a lot of bunk spread around regarding MIM. It's certainly not perfect, but then neither is billet steel. Improper heat chemistry, sulphide/phosphide inclusions, improper heat treatment, inadequate thermomechancial processing, and a host of other process variables can afflict wrought steels and render them susceptible to fatigue, just like MIM has it's own set of problems. Nothwithstanding, Kimber does seem to have some reputation for failures in their MIM parts.

I thought the original post was very valuable because over on the 1911 board there has been a ton of speculation into what parts were MIM on the Kimbers. At least we get it straight from the horse's mouth here.

Zirc