Casehardening on MIM parts.

[Milton]

Does anyone know if MIM parts in a S&W revolver can be casehardened with Kasenit?

 

[bobsav21]

This may help.
MIM Heat Treating | Metal Injection Molding | Dynacast

 

[Milton]

Thank you ! according to that someone can surface harden MIM,I am supposing with Kasenit.I noticed the parts treated are to be stress relieved.

 

[walter o]

From what i have read mim parts for firearms are hardened through and through dew to the material composition mix before molding them . Case Hardening to give them a hard surface is unnecessary.

 

[Tom S.]

As stated, MIM parts already have a case hardening. Unless you've done something to remove that hardening, no hardening is required. From my limited amount of work on them, I've found them to be very hard. I would guess around 60 on the Rockwell C scale, which is about what tool steel typically hardens to.

 

[Milton]

Thanks for the added help! If indeed the MIM parts are the same harness throughout that would be nice .
Can you point me to a site that would actually show this?

 

[Fishinfool]

If color / appearance is the main goal, instead of heat applied, maybe a chemical case color similar to what Ruger uses on some of its frames? For what its worth, I believe I have read MIM parts are hardened thru and thru, but I cant quote a source off the top of my head.

Larry

 

[JHB51]

They are the same hardness though out. The link explains the process. Metal Injection Molding Process - MIM Process

 

[lefty_jake]

Post #4 of the Smithing FAQ contains a famous post about MIM from Smith & Wesson engineer Herb Belin.

http://smith-wessonforum.com/s-w-smithing/94072-faqs.html

In that post, Mr Belin states that the hammer and sear are case hardened. It is possible that he was wrong (unlikely), or that methods have changed.

Recently, I have seen posts from people I consider highly knowledgeable stating that the hammer and trigger are hard all the way through. If anyone has more detailed information, I will be very interested.

 

[JHB51]

I spent 9 years machineing PM parts in a powder metal plant. It may be possible to case harden PM parts I don't know. The only reasons to case harden are for better wear with cheaper material, to keep the soft core for better shock resist, or looks. The only one you will get that info from is a S&W enginer that is if it is not a compeny secret.

 

[Milton]

The problem I am running into is what I am seeing on this thread,some say the parts are hardened all the way through and then someone says they are casehardened.
The reason I want to know is if I get a revolver to repair that has MIM trigger/hammer and someone else has cut or polished the metal am I dealing with a soft or hard interior?

 

[JHB51]

I would replace any parts some one worked on with factory new. This is the way the factory handles it. Law suits can be very expensive. Ask your insurance companey for there advice.

 

[Tom S.]

They are the same hardness though out. The link explains the process. Metal Injection Molding Process - MIM Process

From what I've read, I'm not sure that's true. What I read said they were case hardened after making. In some regards, having them hard through out would seem good, but parts hardened that way can break or even shatter. Leaving a softer core allows some deformation under stress without breaking or even cracking the part, while the case hardness allows for a durable wear surface.

 

[Milton]

I hear you on the insurance and I only work on a very few revolvers that belong to friends and that rarely.I just was curious about the hardness of MIM parts and any necessary repairs that might come down the road.

 

[JHB51]

There ways to find out call S&W may be they will tell you. Send a hammer to a lab for testing. Problem is it has to be a destructive test. Non destructive test won't tell what you want to know. As far as material goes what they use has a lot to with it For example in tool steel S7 has high shock resistance wear resistance fair. D2 has high wear resistance shock resistance is not very good. This type of steel is expensive it is used in stamping dies, forming tools and such. It all comes down to how much money you are willing to spend to find out.

 

[walter o]

Try this for an explanation of MIM
The truth about MIM – Gun Nuts Media

 

[Tom S.]

Try this for an explanation of MIM
The truth about MIM – Gun Nuts Media

That's a very good article in being a simple explanation of the process. Unfortunately, pro-MIM people will look at it and say "See, I told you so" while anti-MIM people will say the same thing. The key element to take away from the piece is that MIM quality depends upon the manufacturer, but in reality that applies to any product made of steel, MIM or not. If a manufacturer does destructive test samples of his product to ensure quality, I have no problem with the finished product, and in fact prefer them for their superior surfaces. Since SW now offers lifetime warranties on their guns, it's easy to see their confidence in MIM's durability, since Smith didn't offer that warranty with the older, so called 'better' parts.

 

[Windageandelevation]

Hello, looking for three nickle side plate screws for model 27-2 revolver