A surprisingly under-discussed topic in the power tools world is the directionality of different saw blades. There are no “universal” rules here; the blade installation direction varies from one saw to the next depending on the type of blade and the type of saw.
Let’s break it down!
How is the Blade Direction Specified?
The blade direction is the direction at which the sharp cutting teeth points. This is usually the path the blade moves or spins in the case of circular blades.
Manufacturers may specify the blade direction on the blade itself and/or on the power saw.
In many cases, you’ll be at a big advantage if the saw you’re replacing a blade on already has one installed that you can copy. However, that doesn’t mean that the installer before you made no mistakes!
This article isn’t a comprehensive blade installation guide, so be sure to check the saw manufacturer’s instructions for blade removal and replacement for that particular saw to be sure your new blade stays put and works as intended.
Overall, there are some clear indicators of the correct blade direction, depending on the saw type below. But essentially, the trick is to remember how the saw moves in conjunction with how the blade cuts, and this will determine the directionality of your blade for installation.
Blade Direction by Saw Type
Following are some of the most popular power saws and their blade directions for your reference.
Circular saws cut on the upward stroke. In many circumstances, you will find guide arrows on both the saw and the new blade, guiding the user to a successful installation. If both arrows are pointing the same way, you’ve done it!
This is an awesome “cheat code,” but if the guide arrows aren’t available in your case, keep in mind the cutting direction. You’ll want the “biting” edge of the teeth pointing upwards to match the saw’s stroke, and the dull, rounded edge facing down or backward.
A Table saw spins back to front, with the back of the saw being the blade guard/guide side and the sharp, biting side of the blade pointing towards you. The back of each tooth on the blade is rounded, and the front of it is sharp.
For most manufacturers, it is standard practice to print any lettering on the side of the table saw blade that will be to your left when standing at the front of the saw. So if you’ve bought a new (or used) table saw that doesn’t already have a blade installed, remember “lettering left”, and “teeth towards me,” and you’ll be good to go.
Similar to the table saw, the Miter Saw spins downward to cut into the wood or other material on its deck. Therefore, the teeth should naturally face down during installation, with the rounded edge of the teeth pointing away from the rotation of the saw.
A scroll saw cuts on the downstroke, so the rake of the teeth on the blade should also then point downward during installation. The blade mount on the saw usually includes a directional indicator, and the pins must fit into the grooves or slots on the blade mount. If the blade isn’t fitting or sitting properly, it may be incorrectly installed.
A band saw blade should always point towards the direction of the blade rotation. So on vertical band saws, the teeth of the blade should be pointing downward. On a horizontal bandsaw, the teeth should be pointed toward the work as the blade is moving. If it’s helpful to you for orientation, the blade direction on a band saw is similar to that of a scroll saw.
Concrete saws are slightly different from the others on this list as their blades are usually diamond blades. This just means that it can be somewhat more challenging to discern which is the “biting” direction, depending on the type of diamond blade you’re working with.
In any case, a concrete saw typically spins downward into the concrete, and the user then pushes it forward to cut. This means that the biting edge should face downward during installation. Some diamond blades have clearly defined teeth, so installation is easy and intuitive.
However, as with a continuous rim diamond blade that may be less clear, directionality-wise, be sure to read the manufacturer’s instructions for installation that are included with the packaging to ensure that you don’t install it upside down or backward.
The jigsaw does most of its cutting work on the upstroke, so a standard blade has teeth pointing upward. A jigsaw is also pushed forward during use, and because the blade plunges to cut with the teeth on only one side, it is quite clear if the blade has been installed backward. Additionally, some mounts won’t properly function unless the blade is installed in the correct position, forcing the user to double-check prior to operating.
There are also reverse blades for jigsaws with teeth pointing downward (used on pre-finished materials to reduce the risk of nicks or chipping), but these would still be installed with the teeth facing out, away from the operator, and towards the work surface.
A somewhat daunting task for some, switching the blade on a chainsaw is nonetheless straightforward when you take into consideration the motion of the machine. The saw is designed to cut in a clockwise rotation outward from the operator, or downward into the material in front of you when the saw is wielded from above.
Once you’ve disassembled the machine, set the saw on the surface in front of you toward your left with the bar to the right. If the “sharp parts” are moving forward, clockwise to the right, then the chain is on correctly, and the saw is ready to be put back together and put to work.
Tips for Saw Blade Replacement
- Before doing any type of work on your saw- cleaning, oiling, repairs, blade replacement- always, always remove your power source. It’s pretty self-explanatory as to why, so just be smart, and don’t be a statistic! Unplug that cord, and take out that battery.
- Whenever you deem it helpful, take pictures of your installed blades or capture a few photos of the blade right before installing. This way, if any of the writing wears off during use, you can easily reference the type of blade, number of teeth, size, etc., and know how to identify it for future projects.
- If you’re ever confused about which way is the “cutting” way, you could try gently running your hand along the (uninstalled) blade. One direction will be easier, the other more uncomfortable. Of course, use a light touch and don’t be reckless, but the “touch test” is a clear indicator of blade direction with most “toothed” saw blades.
- If you’re replacing the blade on a saw for the first time, consider simply googling how it’s done. There is no shortage of professionals on youtube who can walk you through the exact correct steps, and you may even learn a new tip or two.
- If you’re only using the blade for a few cuts or a specific project, consider holding on to the packaging, and returning the blade to it after use. This will keep the “business ends” of the teeth protected from unintended damage, and you’ll be able to easily identify it in the future.
Importance of Blade Direction
Knowing which way the blade shows point can make all the difference when it comes to getting a precise, clean cut. We’ve discussed the “how,” but here are a few “why”s to supplement our above guidance:
- If a blade is installed incorrectly, it can cause a saw to “jump”. This could cause injury to not just the operator, but also to another person nearby, through no fault of their own.
- That “jump” can also damage the blade, especially if it bounces onto or off of a nearby unintended surface. For example, a wood blade isn’t intended to cut concrete or steel, so that blade could easily become damaged upon forceful (however unintentional) contact.
- Imagine spending a lot of dough on a very fine finish material, only to incorrectly install your saw blade and thus damage it. This can be frustrating at the least, but it can also cause construction and project delays if a specially ordered selection needs to be replaced.
- If a blade is installed incorrectly, the saw also may just not work at all or will work so poorly that it will put excess strain on the motor while it fights to “do its job.” Like a blender, when you ignore the “max fill” line and the little engine gets super hot and cranky, these machines are designed to work great when used correctly, but the internal components can be strained and damaged from improper use and can “burn out.”
While incredibly efficient, saws can also be dangerous tools. Be sure to “do your homework” and prepare thoroughly when doing any saw maintenance, and let us know what other topics we can cover to help you with your next project!