The Safety Blade: Everything You Need to Know

If you’re looking for a safety blade, we can make two assumptions: one, you need to cut some material, and two, you don’t want your skin to be that material. You could read safety blade reviews, but to really understand safety it’s important to step back and look at the big picture. Ask yourself, “what is inherently dangerous about this task?” Surprisingly few people do this, even among safety managers.

Of course, a safety blade can never be fully safe because that would mean it couldn’t cut anything at all. But if we understand what makes a blade unsafe for users, we can learn about how different manufacturers try to mitigate those risks. In other words, to make blades safer, it’s important to examine what makes them unsafe in the first place, really delving into the question, “what is a safety blade?”

A Word About Safety Blades vs. Safety Knives

We distinguish here between safety knives and safety knife blades. The two are often used interchangeably, but what actually cuts you: the handle or the blade? Handle designs can keep blades away from skin, but if skin contact is made it’s the blade that matters, which is why it’s important to examine blade safety in depth. For a more general survey of safety knives (the entire tool, not just the blade) see What’s in a Safety Knife? 

Table lists risks associated with knives and which risks can be prevented with better handle design or a safer blade
Only a small portion of the risks users face are addressed by new handle designs, which is why Slice redesigned the blade.

Safety Blades and Their Risks

Blade Tips Can Puncture Skin

The most common way to address this danger is by rounding the blade tips. With many brands, this is the only safety feature inherent in the blade. The rest of their safety claims rely solely on handle design. In contrast, Slice takes a comprehensive safety approach in the design and manufacture of our safety cutting tools and blades.

All Slice tools that offer replacement blades, including our utility knife blades, ship with the rounded tip version by default because rounded tips are safer. Keep in mind, however, that some materials require a pointed tip to initiate a cut. For example, some flexible plastics need a piercing action to penetrate the material effectively. In a case like this, a pointed blade is recommended for reasons of effectiveness rather than safety.

Cutting Edges Dull Quickly

Sharpness is an issue that influences effectiveness but also safety. The more often you need to replace your safety knife blades, the more often you’ll expose your skin to them. Therefore, more durable a blade is, the safer it is.

Blades are most dangerous when they’re either too sharp or too dull. Metal blades spend much of their life cycle in these danger zones because steel is a relatively soft material that dulls quickly. Manufacturers oversharpen the edges in order to give metal blades a reasonable working life. This dangerous workaround sacrifices safety for longevity.

In contrast, Slice ceramic blades are 100 percent zirconium oxide, an extremely hard material. No oversharpening is necessary because the edge holds longer. All our blades, inlcuding our box cutter blades, start at an effective sharpness and stay there much longer than metal. In fact Slice blades last, on average, 11.2 times longer than comparable metal blades.

The Edge Cuts Skin

Because metal safety cutter blades are oversharp, they’re more likely to cut skin. Their grind (the result of the sharpening process) has a deep “initial cutting zone” that doesn’t differentiate between skin and other materials. With metal blades, there is so far no way around this danger.

To address the issue, Slice examined the properties of skin, since that’s the only material you don’t want to cut in a ‘safety knife’ scenario. Skin has a soft inner composition and a flexible but tough outer layer. Our proprietary grind uses a wider cut entrance angle to disperse the force of our blades against skin. Our thicker blades, combined with a smaller initial cutting zone, require much more force to pierce skin than metal blades. We use this same proprietary grind on our safety scissors, making their blades safe to the touch and less likely to cut you.

Cross-sections of Slice ceramic blades and typical metal blades illustrate that the wider Slice blade requires more force to penetrate skin.
The initial cutting zone is defined as the part of a blade’s edge that does the actual cutting. This zone is a result of the angle used to grind the blade. In a metal blade, the smaller angle creates a longer and sharper cutting zone, making users much more vulnerable to lacerations. Slice uses a patented double grind that shortens the cutting zone significantly. This creates an effective cutting edge that doesn’t endanger the user.
Illustration demonstrates how downward force is dispersed with a wider Slice blade, while narrow metal blades go straight into the skin.
Skin is hard on outside and soft on the inside. Slice engineers took this into account when designing our blades. Our wider angle displaces the force of the blade against skin’s tougher, fleshy outer layer. In contrast, with nowhere for the exterior force to go but in, narrow metal blades easily pierce skin.

Note: this doesn’t mean that our knives can’t cut skin! As previously mentioned, the only way to make a knife completely safe is to make it ineffective. Our finger-friendly grind is touchable and much safer than steel blades, but you should always exercise caution around any kind of blade.

Unclean Blades Can Infect Skin

If a cut does occur, any contaminant on a blade, including rust, can get into the skin and cause an infection. Steel blade manufacturers coat their blades in oil to prevent rust. While this guards against one kind of contaminant, it introduces another: the oil coating. Oil can be harmful in a cut and also reduces the blade’s usability in a clean room manufacturing site. In fact, some industries have the additional step of removing this oil coating after they purchase metal blades. This puts employees in danger as it requires more handling of sharp blades.

Slice ceramic blades never rust, and so don’t require any additional coating. Our autoclave-friendly and non-reactive ceramic material is easy to clean and chemically inert.

Blades Come With Electrical Hazards

In the electronics manufacturing industry, sparking and conductive blades pose a hazard for workers and products alike. There’s no getting around this with a metal blade. Slice ceramic utility blades are non-conductive, non-sparking, and non-magnetic, eliminating these hazards entirely and creating a more versatile safety blade.