Exacto Knives: Everything You Always Wanted to Know (but were afraid to ask)

It’s just a simple hobby knife, right? There can’t be much to it. Well, that’s sorta true. It is a simple enough knife so that even beginners can use it with success, but if you take a bit of time to learn all about these knives and the proper way to cut and care for them and their accessories, you will graduate from amateur to professional.

Let’s start at the beginning. What is an Exacto knife? X-ACTO is the brand, and it is a type of hobby or craft knife. Over time, the brand has devolved into the term Exacto, like what happened with ‘Kleenex’ and ‘facial tissues’. There are many other brands that offer a similar knife. This knife might also be called a type of utility knife, but that term generally refers to a larger type of knife with a retractable blade, commonly also called a ‘box cutter’. The Exacto knife was originally invented in the 1930s by Polish immigrant Sundel Doniger’s medical tool company, X-Acto. When an in-house designer needed a sharp edge to retouch a print advertisement, he created a hobby knife similar to his scalpels.

X-Acto Knife


Exacto bladesOne of the biggest assets to this knife is its replaceable and interchangeable blades. When a blade gets dull, or the tip breaks off, or you are simply switching projects and need a different type of cut, the blade can be swapped out for a new one.

There are many different blades, but the typical ones you will likely use are either the #2 or the slightly smaller and finer #11. The most common one for us miniaturists will be the #11. Both are available in bulk, and it’s not a bad idea to stock up on them. I find they are rather interchangeable, but you might develop a preference for your particular projects.

The #11 has an extremely sharp point for fine angle cutting and stripping. The #2 is  just a larger version of #11 blade, its sharp angle is best for precision cutting of medium to heavy-weight materials. The #11-M is a modified #11 with a broader top for a stronger, more flexible point. If you find you break your tips often, the #11-M might be worth giving a try. For doing extremely fine work, a #16 might come in handy. The blade is offset forward a little, so you can easily see what you are cutting.

As for the rest of these, unless you do carving or whittling, you probably won’t need them. If you are interesting in reading about each of these blades’ specific uses, you can read about them (and purchase them) from the art supply company Dick Blick.


In addition to the blade, the knife has a few other pieces to it. These are called the handle, which is the part you hold, the collar, the part that you twist to tighten or remove the blade, and the collet, which is the part that holds the blade in place.

Exacto Knife Parts

There are plenty of different handles available, from the typical craft #2 knife seen after our second paragraph, to the slightly fancier design as seen in our main image, to heavy duty carving handles (#5), and also the classic #1 look, there are even some newer ones that provide cushions or finger grips. Any of these knife handles will work well for crafts. Unless you are wood carving, I’d leave the red #5 handle on the store shelf, because you won’t need it.

The position of the collar can either be right up near the collet and the blade at the tip, or it can be all the way at the back. I personally prefer the slightly cushy handle with the collar at the back. I find I’d rather not be putting all the pressure into the knurled metal; I like my fingerprints as they are, not with an additional cross-hatch pattern. It also helps when cutting curves, so I’m not accidentally loosening my blade when I twist the knife to go around a curve.

The way the knife holds the blade tightly in place is by a screw tightening system. The collar winds up against the collet, which has the blade shoved down into its slit. As the collar gets higher on the collet, the slit closes up around the blade, pinching it in place. It is always a good idea to check if the collar can be tightened before using an exacto knife. You do not want to have the blade come loose while you are cutting!

Tightening and Changing the Blade

To tighten the collar on a typical #1 or #2 knife, ensure that the blade is pushed all the way into the collet. Then hold the collar with your non-dominant hand, and twist the handle clockwise until you can no longer easily twist it. For knife styles with the collar on the end of the handle instead, first check that the blade is well inside the collet, then hold the flat of the blade between your index and thumb on your non-dominant hand, and with your other hand twist the collar tight. Do not use a tool to twist past what you are capable of doing on your own, as this is too much pressure and will make it nearly impossible to change the blade later. It also could potentially damage your knife.

To change the blade, you repeat the same process in reverse and loosen the collar. You do not need to take the knife entirely apart to swap out the blade, just enough that you can pull it from the collet and insert a new one. Do not force the blade out, if it doesn’t come out easily, loosen the collar more. Sometimes, if the collar has been over-tightened, the blade will remain stuck in the collet even after you’ve entirely disassembled the knife. This is more common in old or dirty knives and ones with plastic or rubbery collets. At this point, you should very carefully press the knife blade into a stiff material and then angle the collet up and down carefully until the blade is freed. It may be tempting to try to simply yank the blade from the collet using only your handles, but when the blade does get free, it is quite likely that you will cut yourself in the process. There are no good outcomes to doing it this way, so please *please* don’t do it!

Blade Dispenser and DisposalOnce the blade is out, if it is done for, either put it in a sharps container (a sealed plastic box that the blades can’t escape from) or wrap it in duct or masking tape. The official refill container comes with new blades on the right and a slot for the old blades to disappear forever into on the left, so it’s quite handy. Do NOT simply throw the blade into the trash. If the blade is not yet spent, find a safe way to store it for reuse. Some people sharpen their blades instead of throwing them out when they get dull. There are a bunch of YouTube videos on how to do that if you are interested. If the tip is broken or there are nicks in the blade, it can’t be saved. With the previous blade properly taken care of, you can get a new blade and insert it, back end in, into the collet. Then tighten the collar as instructed above per your handle style.

If you find yourself often having to retighten a collar that repeatedly loosens on its own, it means that the collet and collar threads are worn out and it is time to get a new knife. Remove the blade, say a few words over your faithful friend or laugh at the demise of your enemy (hopefully not after reading this post) and toss it out. Many of these knives are made of either stainless steel or aluminum, so you might be able to recycle it.

Get a Cutting Mat

AlvinCuttingMatsTo use your exacto knife properly, you will also need a surface to cut on and usually, a straight edge or ruler. The best cutting surface is a self-healing cutting mat. They are available at any craft store, and come in various sizes or colors. A popular brand is Alvin, and the standard color is green, but they also come in black or a transparent blue. Other brands make similar sizes and colors as the Alvin mat. I’ve seen mats as small as 4 inches by 6 inches and also ones big enough to cover entire tables. I personally have a 12″ by 18″ and it has always been small enough to be convenient, yet large enough for almost all of my projects. Before that I owned an 18″ by 24″ and it worked well enough in architecture school, but through poor care, I ruined it and had to buy my second mat.

Warped Cutting MatSelf-healing mats HATE heat. I warped my mat simply by having my laptop sit on it. Do not ever set anything hot on your mat. Do not use it as a drink coaster or put a bowl of soup on it. Do not iron on it. Do not leave it in your car. Do not store it in the attic. Do not leave it in your cat’s favorite sunny window napping spot. Heat will warp these mats, and most of the time, theycan not be straightened. There have been a few cases where people are able to reheat their warped mats and get them flattened before they cool, but that can just as easily warp them further. Do not chance it.

Additionally, these mats do not like extreme cold either, so don’t leave it in the basement, or in the garage in the winter, or anywhere else that gets colder than 65°F or so. A cold mat will get brittle and can crack. Also, a dried out mat can become brittle and crack. These mats are made of vinyl and are mostly non-porous but not entirely. Dried out mats dull your blades faster than new or reconditioned mats and they don’t self-heal as well as they used to.

An old mat will benefit from a room temperature soak in a water bath for 15-20 minutes. Make sure that the water is NOT hot, err on the side of too cold. Use 1/4 cup of white vinegar for every gallon of water in the bath. Make sure that the tub you are soaking your mat in is large enough that your mat can lay perfectly flat. If you have any gunk on your mat, maybe fibers from cloth or glue or paint, use a squirt of mild dishwashing liquid (like Ivory) and gently scrub the mat with a soft sponge or cloth. Do not use the green side of a yellow sponge, and definitely no brillo pads. Let it dry flat, and never store it hanging, standing on edge, or rolled.

Always Use A Straightedge

The other tool you’ll usually need is some sort of straight edged metal ruler. It doesn’t have to have ruler markings on it, but it does need to be metal. You use it to make sure your cutting edge is perfectly straight. A plastic ruler is not stiff enough to hold up to a blade skipping, and you don’t want that exacto headed anywhere near your fingers! It’s also quite possible to shave tiny bits off a plastic ruler over time, resulting in lines that aren’t even close to being straight. Bottom line, just get metal.

Cork Backed RulerThe traditional metal straightedge is a metal ruler with a cork backing. I have an old 12″ one, and I picked up two cute 6″ ones during school and somehow acquired and then lost an 18″ one. Choose a size that works well with your project and what you feel comfortable using. The length of the ruler ought to be at least 4″-6″ inches longer than the cut you are making. A ruler that is too short for the project can easily slide around. For this reason, I always use my tiny 6″ rulers cork side down for extra grip, even though it costs me in precision.

A cork backed ruler can be used right side up or upside down. The cork backing provides extra grip to your material, and it is extremely important that your ruler not move while you are cutting, so it’s often good to use the cork side. If you are making insanely precise cuts, however, flipping the ruler over has its benefits. Because the cork raises the ruler up off the cutting material, it’s possible that your cut won’t be exactly where you intended it. You will need to ensure that you are holding the exacto knife entirely perpendicular to the material so you don’t accidentally cut under your ruler. Another issue with using the ruler cork side down is the shadow line. Because the ruler is raised up, a shadow can be cast on your material where you intended to cut, making it hard to see where you planned on cutting. This can usually be avoided by ensuring that your lighting source is in front of you and to your dominant side, but we can’t always control that, so be aware of this drawback.

CuttingGuardsA lesser known option you have for straightedges is a t-section or safe-t cutting guide. It is basically a metal cutting ruler with a perpendicular guard coming out of the center. This is to make it impossible for your fingers and the blade to come in contact with each other. My dad got me two of these, a 11″ and an 22″, early on in my architecture classes, and all my classmates were jealous. Seven years of design school all-nighters, and I’ve never had an accident with an exacto knife. These straightedges can come with ruler markings on them, but mine do not. Some have fancy curve shapes to keep your fingers safe, but I find that the symmetrical sides make it more convenient to use: my straightedge is never facing the wrong way to protect my fingers.


Hold the exacto knife the same way you would hold a pencil or pen, not as a sketch artist does, but regularly as you would to write. Hold the knife securely but not in a death grip. You will be cutting toward yourself. Some experienced professionals are able to cut side to side accurately, but cutting toward you is best as it gives you the most control and the best vantage point.

Most lines can be cut from either direction by simply rotating your material, so you need to choose which way is best for your cut. One way to decide is to put the side that has more material left after the cut under your straightedge. This will give your ruler more to hold on to so it won’t slip. Another good way to decide which way to cut is to use the ruler to protect the part you want to keep. A cut mark can easily go astray away from the ruler, but it’s quite difficult to cut under the ruler. After you’ve positioned your cutting material, you need to place the ruler. If you are right-handed, place the ruler to the left of the line you want to cut, and vice versa for left-handers. Align the straight edge with your cutting line, and only offset it away from the line half a blade-width, so your cut will be perfectly on the line. When you are holding your straightedge in place for a cut, apply as much pressure as you can into holding that straightedge still. It is imperative that your ruler not be able to move or slip. This is when accidents occur. If your knuckles aren’t turning white from the force, you probably aren’t pressing hard enough.

ExactoKnifeHandPositionNow you are ready to start your cut. Place the tip of your blade at the beginning of your cut. Do not angle the knife left or right, hold it perfectly parallel to the ruler. Angling it either direction won’t put the blade on your cutting line, and also will give you an angled edge cut (not generally what is needed, but keep that in mind for special cases). Lower the handle until there is only a small amount of space left between the rest of your blade and the cutting material. It should be a bit shallower of an angle than what you typically use to write with. Having it angled too high increases the likelihood of your tip breaking. Your first cut should be very light. You just want to make a cutting score for your blade to follow on the second cut. Your first cut is the most important, so put more focus on making it straight than trying to make sure it cuts all the way through. You shouldn’t go fast, but going too slow makes it easier to have wobbles in your line. Go about the speed you would go if you were using a highlighter on a line of text.

For your second pass, apply medium pressure, and it should cut all the way through, though some thick cardstock materials might require a third pass. If you can’t make it in two or three cuts, either your blade is dull, or you are trying to cut something that might be better cut with a different tool. Do not just apply more pressure. A knife under that much force is bound to skip or make an incorrect cut. Don’t risk your fingers, either change your blade or find a different tool for the job. Do not just keep making more passes over it either, this will dull your blade and make your cut fuzzy. A clean cut is what we are after, and you can’t make those by repeatedly chewing at the material with multiple passes.

If you are making a long cut, you will need to reposition your ruler holding hand during the cut. Hold the top half of the straightedge first, and cut halfway down your material. Then, without lifting your ruler hand off the ruler, or moving your knife at all, walk your hand down the cut. To do this, keep your thumb tightly pressed against the ruler and lift up on your index/middle/ring fingers, then bring them down to where your thumb is. Have them take the place of your thumb, then move your thumb to be lower on the ruler. Once your hand is repositioned, and your ruler has not moved, you can continue the cut. Repeat as necessary for the length of your cut.

xacto_knives_exercises_blogSome cuts you can’t make with a straightedge, like a rounded corner, or a circle, or a weird squiggle. Sometimes you can find objects to use to help you, like soup cans or coins, but other times you are just going to have to rely on your own skill. To help you get better at freehanding, I’ve found an exacto knife cutting practice worksheet that you can download, print, and practice with. Practice makes perfect!

Once you are done with cutting, you need to safely store the knife. Many knives come with covers similar to a pen cap, and they work quite well. If your knife does not have a cover, you can remove the blade and place it in the knife backwards, so the cutting edge is inside the collet, and nothing too sharp is exposed. Do not leave your knife somewhere it can roll away or off a table. A drawer or tray is best, as long as the blade is covered.

Now that you know all about how to use and care for your knife, mat, and straightedge, you’ll be a pro in no time!

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This article has 7 comments

  1. DIYQueen Reply

    This is informative! I’m no stranger to X-Acto knives, as I’m a veteran DIYer, but this is a great article. When I’m not using my X-Acto knife, I keep it in a toothbrush container. It’s a plastic one you can get for $1 at Wal-Mart. I did have to stuff some fabric in one end because the knife is shorter than the container but it works great. It’s covered up and not a danger to me or anyone else. Just thought I’d pass that little tip along to you guys. :)

  2. Katherine Reply

    Wow! What a fantastic article! Very informative. Thanks for posting it.
    I can’t believe I never knew about those straight edges with safety guard. :)

  3. Anonymous Reply

    I tried to replace the blade of my hobby knife but the collet tightened and can’t replace my blade anymore

    • Smallhouse Models Reply

      Take a pair of pliers and super carefully grip and turn the collet to release it. Please don’t hurt yourself. If it’s still stuck, buy a new knife, they aren’t expensive, but a trip to the ER to get stitches is!

  4. Kat Reply

    Please help! My x-acto knife is one of the retractable ones that pulls the collar and blade back inside of it. However, the blade pulled out and I can’t get the collet to loosen for the life of me to put in a new blade. It turns around and around but nothing happens. Any idea what to do?

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