I thought I would share part of our journey and explain more detail about the thought process that goes into the stainless steel grades and the material we choose to use in our machined Carbon Cx-316L double edge(DE) safety razors.
As you explore your options we thought we would shed some light on the machining and properties of the iron alloy grades of stainless steel commonly found in safety razors or DE razors. We believe we use the best choice grade of stainless to create quality heirloom shavers for your wetshaving experience, lets get started:
First, we need to discuss the grades of stainless used in safety razors, the machinability of different stainless steel grades and why we choose to use grade 316L or what is commonly called “marine grade” stainless steel. When it comes to stainless steel, not all stainless steel is the same, some grades used in double edge safety razors include:
- Stainless steel Damascus(304 & 316)
MACHINABILITY RATINGS OF METALS
The American Iron and Steel Institute (AISI) ranks the ease of machinability of a metal by assigning it a number. These numbers rate the ease of machining a metal and are referred to as a “Machinability Rating” or “MR” numbers. This allows machinist to compare how much it will cost(and the speeds and feeds) to machine a particular grade of metal.
Here is how it works, an arbitrary grade of steel was used as the bench mark (160 Brinel hardness B1112 cold drawn steel machined at 180 surface feet per minute). This material was given a ranking of 1.00. All other material is compared to this bench mark material. If the machinability rating is higher than 1.00 it is easier to machine than the 160 Brinel bench mark, if it is lower than 1.00 it is harder to machine.
Below is a ranking of some material that has been used in safety razors(easiest to machine at the top) and their “MR” rating:
NOTE: The "Darwin" razor was made of Cobalt in the 1930's. Wicked hard and heavy material!
*Numerous grades of this material are available, MR rating depends on the grade.
Listed below are characteristics and general properties of each of these grades of stainless steel. I should note that tap water is a saline solution which has salt(albeit less than the ocean), some households have more salt than others. If you live by the coast you will have a higher salt content in the atmosphere, if you have a water softener system, more salt is added to your water.
STAINLESS STEEL GRADE 303
- Grade 303 is also called “Free-machining” stainless steel
- Sulfur is added to the material which make it a far less expensive grade of stainless to machine than other stainless grades. The sulfur creates voids in the material which allows you to machine the stainless steel quicker, cooler and with no coolant.
- Because of the sulfur, the chips break off smaller and more easily thereby reducing heat on the work piece and extending tool time.
- Ease of machining makes it much cheaper to machine, however it comes at a significant expense to its corrosion resistance.
- 303 is not recommended for earrings, watches, rings or for food applications...in some countries it is banned for these applications. Page 14.
303 is typically used for nuts and bolts...shaving companies who use this material recommend you remove the blade after use, so as to not get rust or tea stains on your shaver. It is more prone to rust and will corrode quicker than other stainless steel grades over time.
Smaller 303 Chips:
STAINLESS STEEL GRADE 304
- Often referred to as “Food Grade” stainless
- Sulfur is not added to 304 which makes it more expensive to machine than 303.
- It is more resistant to corrosion and pitting than 303 but not as good as other grades.
STAINLESS STEEL GRADE 17-4
- Sometimes referred to as “Surgical steel”
- Very similar material characteristics to 304, however 17-4 is slower to machine.
- One of the characteristics of this material is its hardness, especially when heat treated.
- The corrosion resistance is similar to grade 304, this material is not as corrosive resistant as 316L.
STAINLESS STEEL GRADE 316L
- Referred to as “Marine Grade” and “Surgical” stainless.
- Molybdenum is specifically added to this grade of steel to enhance its corrosion resistance, this additive also provides better protection to “pitting” corrosion.
- Commonly used in medical (implants), marine and military applications where the best corrosion protection is required.
- The addition of Molybdenum also makes this stainless grade harder and therefor takes more time to machine and polish. It is significantly(2x) more expensive to machine than 303(See "MR" rating above to compare).
- The chips from machining are longer(see image below), heat is retained on the work piece resulting in slower machine times, higher tool wear and coolant is required to machine this grade.
- Often times grades 316 and 316L are dual certified i.e. the material qualifies as both grades, however technically the “L” refers to the “Low” Carbon variation.
- 316L will finish to a higher polish with more work than other stainless due to the addition of molybdenum. Polishing and finishing will be discussed further in an upcoming blog, but to touch on the subject, polishing to a high polish has 4 benefits: 1) Further enhances corrosion resistance in material 2) Easier to keep the surface clean 3) Aesthetics 4) Less friction on the surface(skin).
Longer 316L chips:
- An exotic stainless steel material that we use. Our material is custom forged in the USA for us and consists of grades 304 and 316
- Both grades have a higher resistance to corrosion than grade 303 (As discussed above).
- You can see the corrosion resistance qualities of these stainless grades in the image below. We etch(controlled corrosion) our Damascus in warm acid, after machining. The acid attacks grade 304 much quicker than the 316 and reveals the grain in this forged material.
The true technical secret to making Damascus steel was lost to time in the early 1900s and has never been replicated. Today “Pattern welding” is often referred to as Damascus steel as the techniques of folding, hammering and forging the steel are similar. Stainless Damascus is different to the carbon Damascus used to craft expensive knives and straight edge razors, Carbon Damascus is a harder steel and will hold a sharp edge better than stainless Damascus but Carbon steel is also inclined to rust much more and requires more care. Our stainless Damascus steel is not as corrosive resistant as Cx-316L but damn….it looks cool!
Note: In this stainless Damascus image below, the valleys are 304 stainless and the peeks are 316. The acid etch corrodes the grades at different speeds...
OTHER MATERIALS USED IN SHAVERS
Now we will turn our attention to discuss other metals that are used in shavers. Titanium, aluminum, copper and brass are other examples of common material used in safety razors. Listed below are characteristics of each of these materials.
We use grade 5 titanium (6Al 4V), most manufacturers do. This Titanium alloy is commonly used in the medical, military and aerospace industry. Grade 5 is an alloy consisting of 6% aluminum, 4% vanadium, .25% iron and .2% oxygen. Titanium alloys are often referred to as “Super alloys.” Pure Titanium is referred to as grade 1 and is not as strong as its titanium alloys. What makes this material awesome for safety razors, besides its intense corrosion resistance(Higher than 316L) is its light weight and hardness, we consider this a better option than 17-4 stainless. Titanium is almost half the weight of 316L. We currently offer the lightest titanium razor on the market. The Titanium we use is USA sourced...
This metal is a very inexpensive material, super easy to machine and very light however in a wet environment it will corrode quicker than all stainless-steel grades, this material is particularly prone to "pitting corrosion". Often a coating is applied but this will wear off either by use or crack when the DE razor is inevitably dropped, the aluminum will corrode at the crack and where the raw metal is exposed, from there it will spread. The material is not as hard as stainless and can bend if dropped. We do not use Aluminum because of it’s softness, corrosiveness, and "bend-ability". Instead we believe Titanium is a better option for a light weight heirloom razor.
Brass is more expensive to machine than aluminum, and is a visually beautiful material. Brass is slightly easier to machine than Stainless 303. It’s corrosion resistance is very good and was often used in marine applications prior to the invention of 316L stainless steel. This material is softer than stainless and is also prone to bending if dropped. Brass will develop a “patina” and change surface color over time. Brass is an alloy of zinc and copper...
This has an ancient history and is a visually beautiful metal, it polishes nice and makes for a gorgeous razor. Like brass it can bend if dropped and is generally softer than brass(depending on the grade). Copper is quicker to machine, although it can be tricky as it tends to be sticky or gummy. We machine this metal with no coolant as the work piece can be kept cool at high speeds. Copper also has other unique qualities including strong heat displacement and it is well known for its antibacterial qualities, which makes for a unique metal to use in wetshaving.
Mokume-gane loosely translates to “wood grain metal” because of the wood grain pattern that is created during the forging process. This material was originally developed in Japan to decorate the Katana swords, used by the Samurai. This material is similar to Damascus steel in that it has layers of forged material. We have our material custom forged in the USA, we use both copper and brass. Like brass and copper mentioned above, this material will develop its own unique patina that will evolve over time. This material is very expensive to forge, more expensive than stainless Damascus to forge.
Chrome plated razors are usually made in Pakistan, India and China where environmental controls are lower, in the US chrome plating is heavily regulated by the EPA. These razors are very inexpensive and shiny. The razors are typically poured into a mold and then chrome plated. These razors will not last, will break and are toxic to the environment or to the people who make them. Generally these razors will fail at the weaker threads or the chrome will crack when the razor is inevitably dropped. This crack will expose the material under the chrome and will corrode and bubble inwards overtime. Vintage models were often chrome plated brass which lasted longer but modern versions are chrome plated Zamak. Very affordable but will not last as an heirloom. You can spot these pieces by the rounded corners and edges, a tight machined edge is hard to cast and chrome plate...
Machined Titanium design with tight machined edges for maximum blade "pinch":
QUESTIONS TO ASK THE MANUFACTURER WHEN RESEARCHING A SAFETY RAZOR:
1) What grade of stainless do you use? Often this information is not clear, vague or hidden. - Carbon Shaving uses 316L.
2) Where is the material sourced? - Carbon Shaving Co. sources its 316L from the UK, Germany or USA. Our Titanium is USA sourced only. All our Damascus and Mokume-Gane is forged in the USA
3) Are all parts of your razor machined? - Often a manufacturer will state “machined” but they machine the handle and provide an inexpensive chrome plated shaving head. All Carbon Shaving Co’s parts are machined.
4) Where are your razors made? - Often times a manufacturer will import their product from China, India or Pakistan and put their logo on it. Carbon Shaving designs, machines and finishes all our razors in Minnesota USA.
5) The above article references "Society of Automotive Engineering(SAE) grades of stainless steel e.g. 303, 304, 316L and 17-4 but many grade standards exist including ASTM, UNS, BS, etc...all relatively easy to verify if a manufacturer will share specifics. While these standards are different they are specific, so the same metal might be called by different grades(Google is your best friend). Ask for specifics....
Anything to add? You have a thought? Leave your comment below...