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Safety Razor Design and Construction – Alloys

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Necessity is the mother of invention. Straight razor shaving was not safe in a lurching train lavatory without risk of serious injury.  Early safety razors were invented  at the end of the 19th and turn of the 20th century.  The razors were 3 pieces (sometimes 2) and the design is still in production and use.  Later in the 20th century ,the one piece, or Twist To Open razor was invented, and both 3 piece, and TTO razors are still in use.


The head of a safety razor is a precision part. Whether Open Comb (OC) or Safety Bar (SB), the tolerances must be fairly tight.  The distances between OC tines, or the SB to the razor head’s base plate have to be exact or no two razors would ever shave the same. (That point made, a razor head is a precision part that will get light use under normal conditions. It is not a part on a Mars Rover, nor is it a scalpel handle used 18 hours a day, which may be dropped three times a week). Metalworking around the turn of the 20th century lagged behind, in its ability to make precision parts. It was difficult to mold brass into a delicate skeleton of a razor head for plating over it.  The handle was never the issue, but a brass head, for plating presented problems for that time period.  The solution was to use a “pot metal” always zinc based (which could be smelted at lower temperatures) for pouring into a mold of a delicate razor head. Gillette was the first to be able to cast delicate brass razor heads for plating. Modern zinc alloys like Zamak 7 approximate brass in strength. Zinc is a highly reactive metal. It’s soluble in acids and bases, and can be affected by exposure to even water, (unless distilled and de-ionized).  Many manufacturers still use Zamak in their razors, with great success.  If the plating remains intact, and the razor is not subjected to trauma, it can last many years. Solingen and Sheffield are the bases for edged steel weapon manufacture in Great Britain and Germany, yet there’s no steel in the  Merkur, Muhle, or EJ razors made in these cities.


In the 21st century, aluminum is used to manufacture some razors.  Advertised as “aircraft aluminum” the exact alloy used in these razors (Standard and Shave Craft) is unlikely to be alloy 7075. That alloy is the only true aircraft aluminum. It is strong and light, approaching some steel alloys. It is very vulnerable to corrosion, making it an unlikely choice for a safety razor.  Other alloys of aluminum are also used in aircraft, (6061, 2024, 5052,6063, and 7068).  The manufacturers do not divulge which alloy is used in their razors.

Aluminum is almost as reactive a metal as zinc is. It also is soluble in both acid and alkali, and easily interacts with many common compounds. One of earths most abundant elements in the crust, it was almost unknown in metallic form until bauxite was mined because it is so chemically reactive, and exists mostly as salts. Ruby, Sapphire, and Zircon are all hard stable aluminum salts called Corunda.  Most aluminum alloys also contain zinc. Aluminum’s relatively low melting point makes it ideal for molding even complex shapes, like razor heads. Plating is not needed. Shavecraft aluminum heads are sintered, while the Standard is machined from a billet.

Finally we come to steel. An alloy of iron, carbon, and other elements, steel is the strongest metal for the manufacture of any precision part, like a razor head. Both aluminum, and brass oxidize to form patinas, which are harder than the metals themselves. These patinas are protective of the underlying softer metal. These are Alumina, and Verdegris, (which gives the Statue of Liberty its hue.) Conversely, the rusting of iron attacks the underlying harder metal, leaving red, brown, or black rusts. Stainless steel (SS) was developed to fight this process. Despite the Teutonic reputation for accuracy SS is not rust free (rostfrei), it is rust resistant through chromium content, and stains less. Increase salt and oxygen in a local environment and stainless steel will rust albeit slowly.

Two groups of stainless steel razors are available. The first group are machined from a single billet of stainless steel. Most metal is cut away until the form is finished.  No plating is required. These are the spendy razors like Razorock, Wolfman, BBS-I, Pils, Tradere, and ATT. The quality of the steel that remains after machining is not a known. Pre machining forging of the billet matters. Traditional machining processes often involve a significant amount of waste of materials. Weber, Feather, and Ikon use sintering technology on their razor’s head, and the head may be a different alloy (17-4 PH in the Weber Head 316 handle)).  Stainless steel is classified by its crystalline structure as either ferritic, martensitic or austenitic.  The Weber has an austentitic steel handle (316) and a ferritic sintered head. It is cheaper to use sintering than machining and this is reflected in the Weber’s lower price. Sadly it has not lowered Feather’s or Ikon’s prices.  The Rockwell is neither sintered nor machined. It is hot forged, which is not a process I’d use with stainless steel.

Critics of sintering are mistaken. Sintered parts have proven to be equal to machined parts under most conditions.  Any porosity of sintered parts is easily controlled at the time of manufacture, and these parts are the equal of most machined parts. This is verified in the metallurgic literature. Since we are talking about a razor, which will only get light use under non -hazardous conditions, it is silly to split hairs over which steel is better.  Unless you are planning on shaving on Jupiter, or using your razor as in impact hammer,that is!

L.M. Isaacs, M.D.

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21 thoughts on “Safety Razor Design and Construction – Alloys”

  1. I have many new in the box vintage Gillette’s from the 20’s, 30’s, 40’s, 50’s, and 60’s. My NIB Toggles, Aristocrats, Rangers, and Milord’s stay in their cases in their original sales boxes. I have about 30 other Gillette’s in rotation as my shavers. I just re-plated 3 notched 48-50 super speeds (My daily shavers) using nickel sulfate hexadydrate crystals, distilled water, and a nickel anode. The process is very simple and uses + & – current from 2 D cell batteries. The result was very nice and thick. I had a few pot metal head Merkurs and sold them all and now only use Gillette’s which I feel are far superior. I do have a few expensive stainless steel razors which work great but I like the vintage pieces.

  2. Correction – RazorRock razors are not Steel, they are manufactured with Brass for the TTOs and Brass/Zamak for the three piece models, some may have steel handle but that is all.

  3. If sintering is as precise, why does it seem to require either a plating/coating or a manual buffing? Couldn’t manual buffing risk altering a razor head’s geometry? Conversely, aren’t some CNC machines able to apply a brush finish in a precise, automated fashion?
    Also, while the homogeneity of a stainless alloy billet may be less known, the alloy of metal powder used in sintering is usually not disclosed to consumers (Weber is the only one that I know which does). Conversely, CNC machined razor manufacturers usually advertise the specific alloy used in their razor heads. Likewise, the alloy nor the thickness of plating/coating on sintered razors is usually not disclosed. Aren’t these alloys and plating thickness telling aspects of a metal’s longevity? For instance, couldn’t chrome that is thin and porous electrochemically cause the underlying steel to corrode (even without the protective barrier being damaged)? Also, even if the chrome is thick and high quality … if scratched, could it still cause the underlying steel to rust through galvanic corrosion or a capillary effect?
    Plus, if any plating/coating is ever scratched or chipped, is there a DIY repair? Conversely, with bare stainless can’t you often buff out minor scratches with stainless steel polish and a toothbrush or buffing pad?
    In regard to manufacturing tolerances and blade exposure (likely the most significant factor in a razors protectiveness and efficiency), what level of precision do you believe significant? Could say a 0.1 millimeter difference in exposure may cause a discernible difference in the shave?
    While I enjoy layman’s research on these topics, I do not have professional experience nor in-depth knowledge, and I appreciate you sharing yours!

    1. Apology for any delay. The sintered head of the Weber is simple polished/finished. Sintered parts are NOT always coated or plated. ShaveCraft might, on their Aluminum razors, but I am not sure about this. At worst the strength of the sintered part is 95% of the machined one. In terms of a razor that is more than enough. I have the Standard, and the Weber, yet I favor my Parker 26C shave over both, (it is a plated Zamak razor). In the end it is all about the shave, not the mass spectroscopy!

      1. To my knowledge, all of the sintered razors are coated or plated or heavily manually buffed. I presume that raw sintered metal has a slightly bumpy appearance? Would these bumps affect the head geometry?
        I certainly can’t argue that your Parker 26C might give you a superior shave, but what percentage of Parker 26C razors do you think might not be as good as yours due to manufacturing inconsistencies?
        In the end, once a person has a razor they are happy with … that’s great. But as a consumer advocate of sorts, I’d prefer to help people to find a great razor without having to buy a dozen different razors…..

        1. Buffing will not alter the geometry of a stainless steel part. You cannot take scratches out of stainless steel with a toothbrush, and the whole point of stainless steel is to avoid having plating which could be damaged under trauma. The passivation process by adding chrome to steel means it is self annealing and won’t spall or rust beyond a superficial staining and or pitting. Those events are more likely to occur where NOx and SOx levels in the air are high causing acidic air. Most razors are already overbuilt for their purpose. The persistence of “Bakelite” slants, made from plastic proves that. A machined Stainless razor should last you a millennia or so shaving.

          1. I really appreciate your insight on these questions!
            I agree with your “whole point of stainless steel is to avoid having plating which could be damaged under trauma” … so why does Feather plate their (sintered or MIM) razors? And why does iKon apply a coating to their (sintered or MIM) razors?

          2. How much metal is removed by buffing out the texture of a sintered part? I realize this it is going to be very small, but do you think it could be as much as 0.05mm? There is an old Gillette “New Salesman Training Manual” which discusses that their adjustable razor goes from mild (0) to aggressive (9) through adjusting the blade exposure by just 0.2 millimeters (and a 10 degree difference in the steep shaving angle).

          3. NOTE: My bad on the buffing with a toothbrush … that was more intended as a DIY removal of trace rust from stainless steel.
            However … I think a buffing pad and stainless steel polish might work well. And again … I don’t think there is a good DIY fix for a plated or coated razor….
            My point is more that I agree with you that sintered razors should cost less than the CNC machined ones. They are without a doubt excellent razors, but given (as you said above) that the iKon and Feather razors are in the same price range as some CNC machined ones … I believe the CNC machined, unplated/uncoated stainless steel are often going to be a better value (unless your skin requires a razor that is as protective as the AS-D2, or iKon OSS … which I don’t think the CNC manufacturers currently make).
            Again, thank you for all of your insights.

      2. Also, what do you think was the cause of the Weber “Wavy Blade” issues that they temporarily had? Not issues with manual polishing I presume?

        1. No idea. My Weber PH has functioned perfectly for over one year. I used a 60 year old SS Flare Tip today. (Not a drop of steel in it) which functions perfectly and still shines. It will probably be working in another 60 years. I would not speculate on why Weber had problems. I also would not blame it on sintering unless you have some specific information I do not.

  4. Merely reflecting the fact that the razor’s quality depends, in part, on the quality of the billet employed, Machining does not have any influence on the quality of the steel. A machined razor from a lower quality piece of steel, is not always better than a well sintered head made up of a higher quality steel powder.
    The powdered steel to be sintered is homogenous, while the internal structure of the steel billet is a variable.. As mentioned, pre machining temper or annealing treatment matter, They make the billeted steel more homogenous. Outside of the wet shaving world, sintering is well accepted practice for metal fabrication.. A review of years of metallurgic literature can verify that.

  5. Could you clarify what you mean by, “The quality of the steel that remains after machining is not a known” ?
    Also I’ve read numerous reports of manufacturing inconsistencies with sintered razors (specifically in regards to the Weber “wavy blade” issue, and to Feather’s older AS-D1 model. Do sintering molds warp with age (as has been a speculated cause of the Weber’s issues)?
    Conversely, I haven’t read any reports of such issues with any of the CNC machined razors. Given (as you point out) that many of the high-end, stainless steel sintered razors in the same price range as some of the CNC machined razors … why do you not recommend CNC machined over sintered?

  6. I believe “frame” is meant to include the handle, and head pre plating. Awaiting confirmation of this from Howie Woda.
    Re: Rockwell .Stainless steel can only be hot forged, (by one of several methods). Hot forged steel cannot be work hardened. Adding chromium and reducing the carbon in SS makes it more brittle (less ductile) than other steel alloys.Forging efficiency depends on ductility. A forge requires a huge plant, even to make small parts.
    The blade of a straight razor is a simple part. It is not as complicated to manufacture as a safety razor head.

  7. Very interesting article. Thanks for the clarifications. It seems strange that no modern makers use brass in the head. The Parker 24C (quite a good razor in my estimation) states that the “frame” is constructed of brass, and in this context “frame” means “handle”—the head is the usual Zamak.
    I wonder why brass is so avoided. I would think that Gillette’s discoveries of how to use brass in the head must be known by now.
    There are some razors—RiMei is an example—that seem to be made of stamped stainless steel: fairly thin construction, but pretty sturdy due to steel’s strength.

    1. If i’m not mistaken my Rimei is only part steel. I took a magnet to it oneday out of curiosity. The only steel was in the safety bar piece. The handle looks like it may be brass? The head didn’t get attracted to the magnet. This, despite listing it as “stainless steel”

    2. I believe you are correct. It is identified as an alloy, which says zinc to me. Frankly I could care less as the razor has zoomed to my favorite, beating out the Weber, and Standard. Construction not withstanding

    3. I have been told that dye casting of brass alloys is too difficult for the razors head, that the molten brass begins cooling before the dye has been filled. Parker razors had a project to use brass heads, but the dye casting was too imprecise to be commercially viable. Gillette was the only one to be able to accomplish this feat,(and I have no idea how they did it). A proprietary brass alloy may have played a role.

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