"Citadel" Levertac-92 pics

The Rossi Model R92, a lightweight carbine for Cowboy Action, hunting, or plinking! Includes Rossi manufactured Interarms, Navy Arms, and Puma trade names.
Archer
2000 Shots
2000 Shots
Posts: 3942
Joined: 04 Feb 2014 05:30
Location: SoCal Loco
Has thanked: 137 times
Been thanked: 610 times

Re: "Citadel" Levertac-92 pics

Post by Archer »

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.
Reese-Mo
250 Shots
250 Shots
Posts: 468
Joined: 07 Apr 2021 13:08
Location: Florida Swampland
Has thanked: 1 time
Been thanked: 97 times

Re: "Citadel" Levertac-92 pics

Post by Reese-Mo »

Yap. But things are much better these days.

For the uninitiated - The metal particles are micro fine, perhaps nano fine these days. They're mixed with a plastic goo, and mixed, and mixed, and mixed for damn near forever. Then the stuff is more or less the consistency of stale cookie dough, and it gets fed under high pressure into the mold. That happens with a tapered screw feed machine, similar to plastic injection. The pressure causes heat, which helps the slug of cookie dough thin and enter the mold cavities. There is a short cool down, and you get a raw part. After that the plastic goo is evaporated, melted, burnt, whatever which leaves the part a bit smaller and maybe only 10 - 15 percent plastic. At that time, the part is heated just to the point of melting and the rest of the goo is eliminated while the metal fuses. Now you have a cooked part. Finally after that, depending on the situation, the part may be machined for critical size, given additional surface textue and/or heat treated.

Lots of stuff going on, but the parts are made by the 100's or 1000's, in big batches.

The problem, as you say, is one of workmanship, not process. Most of the shops are 9000 rated so tracking of batches, batch testing, traceability, that sort of thing are accounted for (or should be... gulp).

As we really know, the cost of everything is time. Cutting and grinding take a lot of time. Forging even more time, and casting a bit less time. MIM is even faster and that makes it very cost effective. But its also a specialized process. Its almost always farmed out. I'm sure Ruger is in house. I doubt Colt does any in house. I know that Kahr farms it all out, as also does Charter. Better acceptance testing would help. Then again, when you're trying to get everything out the door as fast as you can make it, some testing is overlooked, or the standards are made wider.

Maybe its the old "Made in Japan" stigma. Once, made in Japan was a sign of cheap knockoff crap. You wanted quality, you got "Made in the USA". Try buying a camera made in the USA, or any decent consumer electronics. Or precision measurement tool. Even those with the USA name brand are made elsewhere. Hell, even Mitutoyo isn't made in Japan any more, but in various plants in western South America. Makes ya long for Made In Japan with those guys...!!! Seiko watches, only the top models are made in Japan. The very top model made literally in a mountaintop lab/shrine. But I digress on that one ;)

MIM is here to stay, but there's no longer any reason to assume its all crap. Most of the guns are using MIM parts in some degree or another and you just don't hear about issues. In fact, I'm not sure any "reported" issues were actual, but just bad opinion of the process as compared to the old known and loved processes. Sort of like Glock was put in a bad light at first. "Don't let your dog chew on your handgun!". These days, plastic frames are no big deal, even sought after.
Archer
2000 Shots
2000 Shots
Posts: 3942
Joined: 04 Feb 2014 05:30
Location: SoCal Loco
Has thanked: 137 times
Been thanked: 610 times

Re: "Citadel" Levertac-92 pics

Post by Archer »

ISO9000:

"The company has a plan."
"The plan is over there in those binders on that shelf."

Mostly the plan is to pass QMS so the company continues to get work.

ISO9001:
"The company has a 10 point plan"
Everyone is briefed on the plan and it is available to everyone on the server.

Mostly the plan is to satisfy QMS certification inspection so the company continues to get work.
Post Reply