Carton knives
A carton knife is a knife with a trapezoid blade that returns into the handle by itself after the cut. Today we classify this design as a Level 1 safety knife. Knives of Level 2 are safer: their blade is secured after every cut, even if the thumb is still holding the slider.
Carton knives
A carton knife is a knife with a trapezoid blade that returns into the handle by itself after the cut. Today we classify this design as a Level 1 safety knife. Knives of Level 2 are safer: their blade is secured after every cut, even if the thumb is still holding the slider.
What a carton knife is
“Carton knife” is the name for a knife used to open cartons whose blade retracts by itself. The blade is a trapezoid blade without snap-off segments and is usually replaceable. The term is older than “safety knife” and is still used by the employers’ liability insurance associations in Germany, for example in the BGHW guidance on opening cartons safely (in German). At CURT, a carton knife generally corresponds to Level 1.
Cartons usually consist of single-, double- or triple-wall corrugated board. The knife therefore only has to cut a few millimetres deep. It does not need a long, exposed blade for that. An exposed blade is more likely to damage the goods inside the carton.
Carton knife or cutter knife?
Both open cartons; they differ in blade and retraction:
| Carton knives | Cutter knife | |
|---|---|---|
| Blade | Trapezoid blade | Snap-off blade |
| Blade retraction | automatic, as soon as the slider is released | usually manual via the slider. The blade can be extended fully. Some models also retract part of the blade length automatically. |
| Typical work | Opening cartons, warehouse packaging | Cutting to size, trades, workshop |
A cutter knife is therefore less safe than a carton knife with a safety level, even with retraction.
Which safety level for cartons?
The CURT safety levels classify knives by their protection principle. Levels 1 to 3 are suitable for cartons. What distinguishes them is explained further down under selection.
Our recommendation depends on how often and what is cut:
- Occasionally: Level 3. The blade stays covered; hand and goods are protected.
- A lot, with changing materials: Level 1.
- A lot, mostly cartons: Level 2.
Even Level 1 is considerably safer than the cutter knife still used in many businesses.
Safety levels 0 to 3 in detail
What to look for when choosing
- Cutting depth: It must match the thickness of the corrugated board. For multi-layer cardboard you need a model with a greater cutting depth. Every product page states the value.
- Blade change: Changing blades without tools saves time when many employees cut every day.
- Disposable knives: Where a blade change is not permitted for quality reasons, for example in pharmaceutical and food businesses, there are knives without blade change.
- Detectable: For food businesses there are versions that metal detectors can pick up.
- Handle: With continuous use it determines fatigue. The material ranges from plastic to metal.
Our selection by safety level
Three models per level that have proven themselves in everyday use. You will find the whole range with filter in the safety knife hub.
Automatic blade retraction
The blade retracts as soon as the thumb releases the slider. This requires correct operation: if the slider is held permanently, the blade stays open.
Fully automatic protection
The blade is secured automatically after every cut, regardless of user behaviour.
Concealed blade / protective hook
Cutting takes place in the narrow channel of a protective hook. The cutting edge is out of reach for hand and goods.
Frequently asked questions
Do carton knives have snap-off blades?
No. A carton knife has a trapezoid blade. Knives with a snap-off blade are cutter knives. Their blade can usually be extended fully, and some also retract part of the blade length automatically. They are therefore less safe than a carton knife with a safety level.
Can I change the blade of a carton knife?
On most models, yes. The replacement blade must fit the knife. The product page states which one it is.
Are there carton knives as disposable knives?
Yes. Disposable knives are available for businesses where a blade change is not permitted for quality reasons, for example in pharma and food processing.
Are there carton knives with a ceramic blade?
Yes, from Slice. These knives count as Level 2 because of their safety grind.
What is the difference between Level 1 and Level 2?
With Level 1 the blade retracts as soon as you release the slider. With Level 2 it is secured after every cut, even if the slider is still pressed.
Which carton knife suits your work?
Write to us or call. Together we look at material, quantity and workplace, and send you samples on request.