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How to Change Snap-Off Blades of Utility Knives

how to change snap off blades

A utility knife is a small knife with retractable blades. It is more commonly referred to as a box cutter. Aside from being handy and easy to store, utility knives have replaceable snap-off blades. It is easy to acquire spare blades at a local hardware store, and some even come with extra blades in their packaging.

In this article, we will answer two questions regarding utility knives. How to change snap-off blades of utility knives? And why do you need to change them? You will see that the answers below just cuts to the point.

How to Change Snap-Off Blades of Utility Knives

Step 1: Use up all or remove the old blade

There always comes a time when your blade loses its sharpness, and good for you, it is no trouble to change the snap-off blades of utility knives.

But before the actual removal of the blade, here’s a fun fact for you. If you notice, there are diagonal lines on the blades. These actually allow you to quickly snap off a section of the blade every time you deem necessary. As you detach and detach portions of the blade, it will be shorter, of course, until you run out of the blade.

I’m not saying you have to use up all the blades. You can always remove the entirety of it if you choose to. So how do you change snap-off blades of utility knives?

Even if the blade has run short, there will always remain a part of it anchored to the casing. To remove that, you want to pull out the detachable bottom part of the casing.

It is generally easier to remove this part for larger knives as you have more room for grip. Essentially, most if not all models have bottoms that are removable. If yours does not come out quickly, just keep pulling it until it does.

Once you have successfully pulled that out, slide the blade all the way out. But instead of going upwards, slide it downwards. There are models that need loosening up to slide off the blade from the casing completely. Most of such models have knobs for sliders. You want to turn this knob counterclockwise to loosen it.

So slide the blade all the way down, and it should easily detach from the slider as it comes off the casing.

Step 2: Fasten the new blade

This time, get your new blade. Put it on the slider the way the old blade was on. Assuming that the top part of the knife is facing your left, then the sharp side of the blade should be towards you.

The hole at the one end of the blade should be placed right where the circle on the slider is. This circle keeps the blade attached to the slider once inside the knife casing.

At this point, you will reverse what you did in step 1. You want to insert the blade and slider into the casing. Make sure it slides up and down perfectly.

When you see that everything works well, you can go ahead and put the bottom part of the casing back on.

When Do You Need to Change Snap-Off Blades

when do you need to change snap-off blades

As efficient as they may be, utility knives have snap-off blades that are bound to be replaced. Whatever precaution you may take, it is hard to avoid the wearing of such blades. Here are some reasons why you need to change snap-off blades.

Unfit for Sharpening

Snap-off blades are particularly thin blades; sharpening them will prove to be difficult. You will need to work on them very delicately in fear of breaking them apart.

Do not even waste time and effort trying to sharpen a snap-off blade. These blades are designed to be replaced once sharpness fades, not sharpened. Even if it has sharpened for a while, it soon will be blunt.

Besides, sharpening the blade degrades its quality of it. It could produce a regularly blunt blade or a ragged one. Such blades could result in a jagged performance that makes unsafe cuts.

It is advisable to snap off a segment of the blade when the topmost has become blunt. Or, with the steps mentioned above, easily change the blade altogether.


Snap-off blades are designed to be replaceable and often rust more quickly than regular knives. If you feel that the blade does not slide smoothly, it may be caused by the rusting of the or dirty blade. Rustiness is an indication that you need to replace the blade already.


Utility knives are just one of the best tools in our age and time. It comes in multiple sizes; it’s easy to use and can be safely handled. Its snap-off blade is one of its great attributes and knowing how to change snap-off blades easily is another plus point.

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