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Razor manufacturing methods: Is Machined > MIM > sintered > casted ?

Wow, this is very similar to forum debates on gun and other machine parts, MIM vs. machined, cast vs forged. These kinds of arguments can go on forever, but I am one, like others on this post, who really enjoy the discussions. Great topic. Who cares if it is "only" a razor? We don't take razors lightly here [emoji5]️
 
Wow, this is very similar to forum debates on gun and other machine parts, MIM vs. machined, cast vs forged. These kinds of arguments can go on forever, but I am one, like others on this post, who really enjoy the discussions. Great topic. Who cares if it is "only" a razor? We don't take razors lightly here [emoji5]️

Interesting ... do the gun forums say anything different? Do they also concur with the direction this thread seems to be going that machined is generally the most likely process to very consistently produce parts that are true to the intended design?

Cheers!
Shawn
 
I'd be interested to hear what they say on the gun forums as well. Although the consequences of metal failure in a firearm are a little more substantial. :-D
 
Slightly different stress involved; 40 kpsi and higher on a rifle chamber, maybe a few psi on a tightly clamped razor head. I think the difference in material processing is more a concern for repeatability in shaping, shrinkage and finishing than strength. Although there is a strength issue for the threaded post where it joins the cap there shouldn't be much stress put on that area, no need to use excessive torque to hold a blade firmly.
 
There is little disagreement on the gun forums, MIM is "bad" and machined is "good." It got so intense that one of the high end pistol makers (Wilson, they make custom 1911 pistols if that means anything to the reader) offered to replace any MIM parts on their pistols with machined pats that they termed "bulletproof." In reality, a lot of the major military manufacturers like Heckler and Koch, use MIM parts, they are cheaper to manufacturer and if done correctly, have the same projected life. The issues that posters objected to were small air pockets that can, according to them, lead to catastrophic failure. In a military weapon, that is an issue. My image of catastrophic failure in a razor is pretty humorous.

Bottom line, they are all solid manufacturing techniques, as others who know more then me have expressed, the issue is manufacturing tolerances and QC.

That said, I have only machined parts in my guns (and I have a legitimate reason to have guns) and in my preferred razors [emoji4]

But that does not mean they are necessarily better in the relevant product lifetimes.

T
 
I know it is an old thread, but still interesting. Some quotes I found om an arms forum, not scientifically verified:

Casting requires molten metal.

Sintering is metal powder only.

MIM is metal powder + flow additive/binder.

With proper QC and heat treatment, there's no problem.

Issues arise because there's little or no QC, which often goes hand in hand with MIM and sintering, since they're usually employed as a cost cutting measure in the first place.
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Sintering is taking metal powder, pressing it into shape, then heating it up to "weld" it together. It doesn't melt the metal into a liquid, just heats it enough to fuse it.

MIM is "metal injection molding" whereas the metal powder is in a binder and pumped into an injection mold like plastic. They are heated after being molded to remove the binder and like sintering fuse the powder together.

Casting is pouring molten metal into a mold.

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Metal experts - sintered vs cast vs MIM? - AR15.COM
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R

romsitsa

It depends on how wide the shim is. If the blade has the same area of contact with the shim as with the base plate, rigidity shouldn't be altered.

Adam
 
I didn't notice the date of the original the tread until I had finished reading all of it. Very interesting and still relevant.
 
doesn't it also alter rigidity?
Shimming, depending on how it is done, may lead to the blade being less supported by the head, since the blade may have more play between the top and bottom parts of the head. The more extreme cases were the now discontinued Fatip and Muhle designs. These razors were considered aggressive but I found their major problem the lack of blade support, leading to a thinner blade dancing over thick stubble. All this can be countered by the use of a thicker/more rigid blade. Anyway, this is why I believe that more modern head designs with changeable plates that are efficient but with proper blade support are often desirable, if you like to change efficiency in one razor.
 
Hi

Interesting thread. I am a designer and an engineer and have been involved with designing machines and never thought razor geometry would be debated so much. Let me add my thoughts if I may.

As far as materials go the best would be Stainless Steels. All grades. Doesn't matter 304 or 316 or 316L. Very hard, high tensile strength and better corrosion resistance compared to anything else (brass, aluminium, zinc, Zamak). Next I would rate Brass. Get good threads (smooth and durable) and has good corrosion resistance. I would not use Aluminium as it is very soft and has issues of pitting. So a razor blade could easily scratch a head made out of Aluminium. Bottom of the barrel are Zinc, Zinc alloys and Zamak. Poor corrosion resistance. Relatively soft.

Regarding manufacturing process highest accuracy would be from a machined head. But with the condition it is machined on a good milling machine or CNC. A head machined on an old rusty mill would be worse than a die cast head in terms of tolerances and accuracy. Next to machining I would go for Die Cast or MIM as it gives relatively good surface finish and tighter tolerances compared to casting. At the bottom comes casting. Interior in terms of surface finish, strength, tolerances.

Coming to surface treatment (coating) Chrome plating often comes as hard chrome plating and soft chrome plating (decorative). Hard chrome plating lasts for years, has excellent finish and is very hard. So difficult to scratch. Next would be processes like PVD which also give very durable hard coating that can last for a lifetime if properly done. The trick in having a durable coating is to have proper pre treatment of the base metal. Lot of small shops do plating just for the heck of if in a very crude way and a crude setup giving the impression 'But plating doesn't past.

So to sum it up, it all depends on to what lengths the manufacturers go to ensure that the base material and the coating are durable. Any razor can look and feel good when new.
 
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