Re: "Citadel" Levertac-92 pics
Posted: 22 Oct 2021 13:05
The simple reason that both MIM and Investment Cast or mainly CAST parts are maligned is that while they are typically fine and cost effective when done correctly, so many producers (or manufacturers/production assemblers) seem to have had teething problems when they either set up the processes OR when they contract out parts to be produced using those methods. Being as business relationships change if the item in question is a contract part that contract may shift from one to another fabricator over time and the lowest bidder may have those same teething problems all over again OR since it IS a process that is somewhat more complicated than simple machining out of a block followed by heat treatment and cosmetic finishing there is more places for errors to be introduced as production staff changes raw material lots or environmental factors change over time.
There have been some of those MIM parts that were either over the edges of the process spec or that may have been made by transitional operators or whatever that have failed and when they fail it tends to get published about as wide as the owner can sing it. There's also been some complaints that the parts tend to be surface hardened and that if you do any fitting on them that once you cut through the surface the insides may show evidence of large grain structure and/or softness.
A hunk of billet (and especially a hunk of billet that goes through a forging die) tends to be a more or less homogeneous solid lump (leaving out the fact that the billet grain structure is slightly better in the rolling direction and that a forging tends to 'bend' the grain structure around curves slightly) that doesn't really care if you decide to relieve the area under the trigger guard a little for a higher grip, or checker the front strap. (As long as you pay close attention to how thin the corner structure can get.) Cast parts on the other hand sometimes still slip through with voids that are uncovered when Joe Bob starts grinding on them. OR Joe Bob may blame the fact that he was free handing with a die grinder on a 'casting void' when in fact he just sneezed at the wrong moment. Since billet or forged then machined frames tend to be more expensive than cast Joe Bob is much more likely to be grinding on a PI frame than he is to be grinding on a one stamped Hartford. When it comes to cast Imbel and Ruger tends to know what they are doing and casting voids aren't exactly likely but once again you may tend to pay a mite more for the part than one coming out of the PI.
Almost every major firearms manufacturer is using MIM processes and you aren't really hearing much about defective parts anymore now that the process has been pretty common for 30-40 years. The billet production for those small parts tends to exist only among the small boutique brands who charge accordingly.
Talking about jet engine manufacturers. It was widely publicized when I was getting out of grad school that one of the companies had produced and run for a couple hundred hours or some such a jet engine that was composite/ceramic without the traditional metallic blades. It was in all the industry trades. One of my classmates was apparently all gaga about it. It just so happened that we had reps from that company on campus for some other purpose and there was a time set aside for them to brief some of the students and take questions. My classmate of course took the op to ask about the engine instead of what they were discussing. He was told, in somewhat milder terms, that they essentially wasted a fortune down that blind alley and all they got for it was publicity in some of the technical trades. NONE of the technology from the ceramic engine would be incorporated into ANY foreseeable future engine production in any way whatsoever.
There have been some of those MIM parts that were either over the edges of the process spec or that may have been made by transitional operators or whatever that have failed and when they fail it tends to get published about as wide as the owner can sing it. There's also been some complaints that the parts tend to be surface hardened and that if you do any fitting on them that once you cut through the surface the insides may show evidence of large grain structure and/or softness.
A hunk of billet (and especially a hunk of billet that goes through a forging die) tends to be a more or less homogeneous solid lump (leaving out the fact that the billet grain structure is slightly better in the rolling direction and that a forging tends to 'bend' the grain structure around curves slightly) that doesn't really care if you decide to relieve the area under the trigger guard a little for a higher grip, or checker the front strap. (As long as you pay close attention to how thin the corner structure can get.) Cast parts on the other hand sometimes still slip through with voids that are uncovered when Joe Bob starts grinding on them. OR Joe Bob may blame the fact that he was free handing with a die grinder on a 'casting void' when in fact he just sneezed at the wrong moment. Since billet or forged then machined frames tend to be more expensive than cast Joe Bob is much more likely to be grinding on a PI frame than he is to be grinding on a one stamped Hartford. When it comes to cast Imbel and Ruger tends to know what they are doing and casting voids aren't exactly likely but once again you may tend to pay a mite more for the part than one coming out of the PI.
Almost every major firearms manufacturer is using MIM processes and you aren't really hearing much about defective parts anymore now that the process has been pretty common for 30-40 years. The billet production for those small parts tends to exist only among the small boutique brands who charge accordingly.
Talking about jet engine manufacturers. It was widely publicized when I was getting out of grad school that one of the companies had produced and run for a couple hundred hours or some such a jet engine that was composite/ceramic without the traditional metallic blades. It was in all the industry trades. One of my classmates was apparently all gaga about it. It just so happened that we had reps from that company on campus for some other purpose and there was a time set aside for them to brief some of the students and take questions. My classmate of course took the op to ask about the engine instead of what they were discussing. He was told, in somewhat milder terms, that they essentially wasted a fortune down that blind alley and all they got for it was publicity in some of the technical trades. NONE of the technology from the ceramic engine would be incorporated into ANY foreseeable future engine production in any way whatsoever.