Let me add that some of the best quality stuff is MIM, and some of the worst is machined from bar stock. It's all in the quality controls.
Ruger makes heavy use of MIM.
How would I recognize an MIM part?
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BobCat
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Re: How would I recognize an MIM part?
7075-T7 is exactly right. Properly done, powder metal parts and metal injection molded parts are just fine - as are forgings, castings, and machined parts. Each process has characteristic strengths and weaknesses, but all can produce satisfactory parts if properly and carefully performed.
People used to ridicule PM because it was developed to make cheap, low-performance parts without machining - think about the gears in a washing machine. Low performance, low cost, work ok.
As the techniques evolved, more and more high-performance parts were made by PM. With good process control and QC sampling, it is as reliable as anything else. Check http://www.crucibleservice.com/products/CPM/index.cfm" onclick="window.open(this.href);return false; for a quick read on how PM tool steels are made (these are not finished parts, the tool steel blanks are made by PM because of the microtructural control it affords).
MIM is just mixing the metal powder with a plastic "vehicle" so it can be injection molded, like plastic. The molded part is heated to drive off the plastic, then heated higher (sintered) to eliminate interparticle boundaries. Properly done, you get a sound, dense part for a much lower cost than machining, forging, or casting - with no (or minimal) secondary operations.
I should not post this - I get accused of being a smart-alec - but the distaste that people express for MIM parts irritates me because it is based on the relative newness of the process. Yes, it is done to save money - that's why a new Armscor (Rock Island Armory) 1911 costs about half what a new Colt 1911 does. But if you read the M1911 Forum, you will find quite a number of people who shoot the Armscor pistol and love it - no problems.
Anything can break (or be broken). If you really are worried, go to http://www.mcmaster.com/#dye-penetrant- ... ts/=5ot9fv" onclick="window.open(this.href);return false; and buy some dye penetrant. Detail strip the pistol, inspect all the small parts with dye pen, replace anything that shows a crack, and get on with your rat killin'.
Regards,
Andrew
PS I'm a Metallurgist too - that makes two of us here so far. Anyone else?
People used to ridicule PM because it was developed to make cheap, low-performance parts without machining - think about the gears in a washing machine. Low performance, low cost, work ok.
As the techniques evolved, more and more high-performance parts were made by PM. With good process control and QC sampling, it is as reliable as anything else. Check http://www.crucibleservice.com/products/CPM/index.cfm" onclick="window.open(this.href);return false; for a quick read on how PM tool steels are made (these are not finished parts, the tool steel blanks are made by PM because of the microtructural control it affords).
MIM is just mixing the metal powder with a plastic "vehicle" so it can be injection molded, like plastic. The molded part is heated to drive off the plastic, then heated higher (sintered) to eliminate interparticle boundaries. Properly done, you get a sound, dense part for a much lower cost than machining, forging, or casting - with no (or minimal) secondary operations.
I should not post this - I get accused of being a smart-alec - but the distaste that people express for MIM parts irritates me because it is based on the relative newness of the process. Yes, it is done to save money - that's why a new Armscor (Rock Island Armory) 1911 costs about half what a new Colt 1911 does. But if you read the M1911 Forum, you will find quite a number of people who shoot the Armscor pistol and love it - no problems.
Anything can break (or be broken). If you really are worried, go to http://www.mcmaster.com/#dye-penetrant- ... ts/=5ot9fv" onclick="window.open(this.href);return false; and buy some dye penetrant. Detail strip the pistol, inspect all the small parts with dye pen, replace anything that shows a crack, and get on with your rat killin'.
Regards,
Andrew
PS I'm a Metallurgist too - that makes two of us here so far. Anyone else?
Retractable claws; the *original* concealed carry