A question of MIM parts

[dirtywaterdiver]

I was just wondering what others think about MIM parts.

I understand the initial concerns but MIM is not what it once was.

Would you replace your MIM parts before there was an issue, or would you wait till, if, a failure occurred.

[sapien]

I am not concerned about the reliability of MIM parts and would only replace them if there was another issue.

[Uncle_Lawrence]

mim parts quality are getting better as technology moves forward, in the future mim parts will mean nothing because they will be as good or better than cast parts. I have no bad comments about the now days mim parts. I have yet to have a problem with one so far.

[ncviking]

Reliability wise they are fine...I never ever had a failure due to MIM parts. The only thing I ever changed was the hammer and sear just because tool steel takes stoning much better than MIM. I still have several pistols with the original MIM parts....never needed to mess with them. I was going to put a Wilson Value Line hammer in a build I'm doing but came across a better deal on a Nowlin hammer....I'll save the Wilson for my next build.

[dirtywaterdiver]

Good insights.

[str8shootr]

I have a PARA Super Hawg with a lot of MIM parts. So far I've replaced the hammer & the extractor (power x ) when they broke. I'm not knockin MIM but I keep some spare parts around. Cast Parts!

[1911Tuner]

I had a guy come to me a few years back with a NRM 01991 Colt Government model. He requested that I replace the MIM sear and disconnect with his new parts. We'd discussed it some weeks earlier, and I told him that it was probably a waste of time and money.

After the swap, I asked him if he wanted to keep his old parts, and he said no...so I did a little demonstration for him.

I laid the sear on an anvil...cupped side down...and gave it 2-3 brisk whacks with a 4-ounce ball peen hammer. It didn't shatter into a million tiny pieces. It didn't even crack...and when I installed it in one of my pistols, it functioned just fine, albeit with a pretty rough trigger action.

Then, I clamped the disconnect up in a vise and whacked it with the same hammer. It bent, but it didn't break.

Good MIM is pretty good stuff. Bad MIM...not so much. Colt has apparently found a good vendor for its MIM parts. In the early days, Kimber did likewise. As time went on, they either changed vendors or their current vendor's QC went down. From what I understand, that problem has been rectified, and they're using good MIM again.

Another part of the MIM problem is using it in applications where it really shouldn't be used. As a rule, it doesn't fare very well with impact. That may have changed with better technology, but I wouldn't bet too heavily on it.

The big problem is that...without an X-Ray or magnaflux test...it's impossible to determine whether the part is good or bad unless it has a visible surface flaw.

[CAWalter]

The big problem is that...without an X-Ray or magnaflux test...it's impossible to determine whether the part is good or bad unless it has a visible surface flaw.

I agree that most MIM parts today are of sufficient quality, just as cast, bar stock, and forged, can be as well. None of which are above the requirements you mention, for proof of perfection.

CAW

[1911Tuner]

None of which are above the requirements you mention, for proof of perfection.

Perfection only exists in the mind of God.

But, I'd be a bit less nervous over an internal flaw in a machined steel part than in a cast or MIM part.

After all, there are a few very good reasons that NASCAR engines all have forged connecting rods and crankshafts, while Granny's Grocery Getter is fine with castings.

[Spyros]

Well yes... but by the same token, there must be a few good reasons why there are airliners flying around with MIM blades compressor vanes in their jet engines.