Things You'll Need
X-Acto blade or hobby knife handle
Replacement blade
Masking tape
X-Acto and other hobby knife blades are ideal for a wide range of craft projects because they are inexpensive, disposable and are incredibly sharp straight out of the box. These blades are meant to be thrown away when they become dull, rather than being sharpened by hand, so keeping a few extra blades around is always a good idea for large projects. Certain tasks, such as cutting heavy mat board or balsa wood will dull blades at an excellent rate, requiring frequent changes. Securing the blade improperly during this step may cause the blade to wiggle or slip during cutting, with potentially disastrous results.
Removing the Old Blade
Step 1
Carefully hold the knife handle with the blade pointed away from you in one hand, and grip the knurled section at the base of the blade between two fingers of your free hand.
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Step 2
Twist the knurled section of the handle counter-clockwise while holding the rest of the handle steady with your other hand. This will release the chuck, which holds the blade in place.
Step 3
When the chuck is loose enough for the blade to move freely, pinch the flats of the blade between your thumb and forefinger and carefully lift it out of the chuck. Alternatively, you could simply turn the handle upside down over an appropriate receptacle for disposing of sharp implements and let the blade fall out.
Step 4
If you are disposing of the blade in an ordinary trash can, wrap the spent blade in masking tape to prevent it from cutting through your trash bag or causing damage during disposal.
Securing the New Blade
Step 1
Carefully remove a fresh blade from its original packaging, holding it on the flat sides of the blade with your thumb and forefinger. For additional safety, you can cover the sharp edge of the blade with masking tape and then remove it after the blade has been secured.
Step 2
Make sure that the knurled ring is screwed all the way out and that the chuck on the knife handle is loose enough to accommodate the tang -- the long, straight, unsharpened metal piece extending from the body of the blade.
Step 3
Hold the blade above the chuck so the bottom of the tang is lined up with one of the open slits in the chuck. Insert the tang into the open slit until it reaches the bottom of the opening, or until the tang is no longer visible. The more of the tang that is secured, the less likely the blade is to slip out or wobble during use.
Step 4
Holding the blade in place with one hand, twist the knurled section of the handle in a clockwise direction to tighten the chuck around the tang of the blade.
Step 5
Inspect the blade and make sure it is sitting low enough in the chuck and is being held securely in place.
Warning
Hobby blades and X-Acto knives are incredibly sharp and should always be handled and disposed of with extreme care.
Always keep your blades sharp enough for the specific task you wish to perform. A dull blade will require more force to cut and is therefore much more dangerous than a sharp blade, if handled correctly.