While many workplaces aim to do the right thing by purchasing safety knives for their employees, some may not be selecting the types best suited to their tasks. Safety knives come in various shapes and sizes, including fixed blades, manually retractable blades, and automatic blades. The sheer variety of safety knives available can be overwhelming, particularly as different brands often use varying terminology. So, what’s the safest choice when it comes to exposed blade knives? In our expert opinion (and that of many others), the two most secure types of safety knives are automatic retraction knives and fully automatic retraction knives. Scroll down to learn more!

What is a Retractable Safety Knife?

Once upon a time, the best safety knife available was the manually retractable type, where the blade is exposed by pushing a slider forward with the thumb. This blade remains exposed until the user pulls back the slider to retract it. While there are still situations where fixed blade or manually retractable knives are advantageous (such as cutting through thick or uneven materials), semi-automatic and fully automatic retractable knives have since been found to provide far superior ergonomic and safety benefits.

The key feature of a retractable safety knife is its spring-loaded mechanism, which allows the blade to retract into the handle, significantly reducing the likelihood of injuries. By giving the user control over when and how the blade is exposed, these knives drastically reduce the risk of laceration accidents. Additionally, these knives do not require a slider to be manually pulled to retract the blade, making them especially useful for repetitive tasks performed over extended periods.

Semi-Automatic Safety Knives

The semi-retractable knife operates similarly to a manual retractable knife but includes a spring mechanism that retracts the blade when it reaches the end of the material being cut, provided the user removes their thumb from the slider. By keeping their thumb on the slider, the user can prevent the spring from retracting, allowing the blade to remain exposed until they decide to retract the blade. One of the main advantages of a semi-automatic retractable knife compared to a fully automatic one is its cost. Typically, semi-automatic knives are more affordable than fully automatic retractable safety knives, as they are based on more established technology, yet they still provide a high safety safe option.

Key Benefits

  • Cost-Effective: One of the main advantages of semi-automatic retractable knives is their lower price point, making them a budget-friendly choice for any workplace.
  • Superior Control: Users have enhanced control over blade exposure, which can be particularly useful for certain cutting tasks.

Fully Automatic Retractable Safety Knives

The fully automatic retractable blade knife functions similarly to semi-automatic versions in that the blade retracts at the end of the material being cut. However, this newer technology enhances safety by eliminating the operator's ability to prevent retraction. Regardless of whether the slider is pushed forward, the blade will retract at the end of the cut. This design significantly reduces the potential for user error by completely removing retraction control from the operator.

If you’re an employer looking for a safe exposed blade knife for your employees, a fully automatic retractable smart knife is the optimal choice. Although it may require a higher initial investment, it offers superior protection against cuts and injuries, with MARTOR fully automatic retraction knives featuring some of the most advanced technology in the industry.

Key Benefits

  • High Degree of Safety: Designed to maximise user safety, the fully automatic retractable smart knife is the best technology available for protecting operators from cuts and injuries.
  • Spring-Loaded Mechanism: Automatically retracts the blade into the handle after use, reducing the risk of accidental contact with the blade.

Key Differences Between Semi-Retractable & Fully Retractable Safety Knives

If you’re still wondering which type of safety knife best suits your workplace, compare the key features of fully automatic retractable knives and semi-automatic retractable knives, below:

Feature Semi-Automatic Retractable Knives Fully-Automatic Retractable Knives
Blade Exposure Mechanism

 The blade of MARTOR’s semi-automatic retractable knives is exposed with the simple activation of the knife’s trigger.

This can be done by either pushing a slider forward with the thumb or squeezing a trigger on the handle, depending on the specific knife model.

The blade of MARTOR’s fully-automatic retractable knives is exposed with the simple activation of the knife’s trigger.

This can be done by either pushing a slider forward with the thumb or squeezing a trigger on the handle, depending on the specific knife model.
Blade Retraction Based on the type of trigger your knife has, you will either release the slider or stop squeezing the trigger to engage the blade retraction at the end of the cut. With semi-retractable knives, the blade is retracted only once the thumb or trigger is released after the cut is started. It will not retract during or at the end of the cut if the slider or trigger is not released. With fully-automatic knife retraction, even if the user’s hand remains on the trigger or the slider, the knife blade will automatically retract back into the handle once contact with the cutting surface is lost, both during and at the end of the cut. There is no need to remove your thumb from the slider or trigger for the blade to retract safely.
Hand Position After Exposure It’s recommended that the knife wielder release the slider or squeeze trigger once the cut is underway. It's important to note that cutting tension keeps the blade exposed, so not releasing the slider or squeeze trigger when cutting is not recommend for optimal safety. Leave your hand on or off the slider or squeeze trigger when using fully automatic knives and the blade will retract automatically once the cut is complete, regardless of your hand position. Even if the operator forgets to release the trigger, the blade will still retract at the end of the cut. This design also ensures that the knife cannot be modified to override this safety feature.
Cutting Tension Requirement For a semi-automatic retraction knife to work effectively, tension must be maintained with the cutting surface, and your hand should be removed from the slider or trigger. If contact with the surface is lost at any point, the blade will automatically retract once your hand is off the control. To work efficiently, a fully automatic retraction knife requires constant tension with the cutting surface. If this tension is lost, the blade will retract immediately, whether or not the user’s hand is on the slider or trigger.
User Error Prevention For maximum safety, the user must intentionally release the slider or trigger for the blade retraction mechanism to be activated. The blade automatically retracts, no matter the hand position, reducing the chance of user error significantly. These knives are designed to prevent accidents from misuse or carelessness. With proper training, employees can quickly adapt to and use the safety features effectively.
Safety Compliance These knives typically include user instructions and safety warnings aimed at reducing the likelihood of accidental injuries, with mechanisms that promote safe operation. Not adhering to the instructions hinders the effectiveness of the blade’s safety mechanisms. A very high level of safety means that, if the operator forgets to remove their hand from the trigger of their fully automatic knife, the blade will still retract once the cut is complete, regardless. The design also ensures that the knife cannot be modified to bypass the safety feature.
Safe Mode Lock In some products, there is a locking mechanism feature that prevents the blade from being unintentionally exposed during transport or handling. When engaged, this lock keeps the blade securely retracted, ensuring that it cannot be exposed until the user intentionally disengages it. This mechanism helps reduce the risk of accidental cuts or injuries while the knife is not in use. In some products, there is a locking mechanism feature that prevents the blade from being unintentionally exposed during transport or handling. When engaged, this lock keeps the blade securely retracted, ensuring that it cannot be exposed until the user intentionally disengages it. This mechanism helps reduce the risk of accidental cuts or injuries while the knife is not in use.
Carrying Safety As the blade will automatically retract when it is not in contact with any material, it means the user can safely store their knife in a holster without the risk of the blade staying exposed. As the blade will automatically retract when it is not in contact with any material, it means the user can safely store their knife in a holster without the risk of the blade staying exposed.
Training Requirement Even with all its safety mechanisms, knife safety must still be always observed when using semi-automatic retractable knives. The correct training and understanding of the knife’s features is recommended to prevent workplace injuries.

Even with all its safety mechanisms, knife safety must still be always observed when using fully-automatic retractable knives, and correct training is recommended if you wish to prevent workplace injuries. 

Correct training entail understanding how the safety features work.

Both semi-automatic and fully automatic retractable knives offer advanced safety features, but the best choice depends on your specific needs.

When choosing a safety knife, consider these questions:

  • What tasks will the knife be used for?
  • How frequently will it be used?
  • Which safety features are most important for your workplace?

At MARTOR, we’re here to help you find the right knife for your business and employees. If you have any questions or need assistance, feel free to contact our friendly team.

Ideal Use Cases

When to Use Semi-Retractable Safety Knives

  • Low-Risk Environments: Best for tasks that are infrequent or involve softer materials.
  • Budget Constraints: A cost-effective option for businesses looking to save while still prioritising safety.
  • Training Facilities: Ideal for environments where users are learning to handle manual controls.

When to Use Fully Retractable Safety Knives

  • High-Risk Workplaces: Suitable for industries like manufacturing and warehousing, where there’s a higher risk of cuts.
  • Frequent Cutting Tasks: Designed for continuous use, offering both efficiency and safety.
  • Compliance with Safety Regulations: Perfect for organisations prioritising safety and reducing liability.

MARTOR’s Safety Knives: Blade Changes and Ergonomic Handles

Ready to improve workplace safety? Consider MARTOR safety cutters or safety knives. Strong and sharp, they’re designed to minimise user error and prevent accidents caused by misuse. Both semi-automatic and fully automatic knives come with ergonomic, lightweight handles, suitable for left and right-handed users, and allow for tool-free blade changes.

You can browse automatic retraction knives here and fully automatic retraction knives here. Head over to the MARTOR homepage to check out our many products and resources. For all inquiries, don’t hesitate to contact MARTOR directly.