A lot of building and woodworking projects call for angled cuts. You make these angled cuts, also called miter cuts, using a miter saw. One of the most common miter cuts is the 45-degree cut.
What are the steps for making 45-degree cuts on a miter saw? You’ll find them below.
Note: Often people first start using miter saws to cut crown molding. Crown molding angles vary quite a bit. To get appropriate miter saw settings for crown molding, look online for a crown molding angle chart. You can then use the steps below to cut your molding, but instead of cutting at a 45-degree angle, you’ll be cutting at the appropriate angles for your molding, according to the chart.
Prepare Your Workspace
This first step may seem basic, but when you’re getting a feel for how to use a miter saw, you want to do everything right from the start. So before you begin sawing, you need the space to work. Making angled cuts requires more precision than regular sawing, so your workspace must have enough room and be well lit.
When you’re learning how to make a 45-degree cut on a miter saw, you need to practice. You’re not going to hit a miter cut home run on your first at-bat. Be sure you have enough scrap wood to make at least a few miter cuts before you even think about making the cut on the wood you’ve purchased for your project. Wood is expensive. Don’t waste it.
Prepare the Saw
This step isn’t necessary if your saw is new or has been recently cleaned and calibrated. But if the saw hasn’t been used for some time, this is an important step.
Proper saw preparation will assure that you get accurate cuts. Here are six steps to get your saw set up properly.
1. Clean the Saw
Sawdust and debris can cause misalignment. It’s a good idea to clean your saw after you use it each time, but if you’re not in that habit, your saw may need a bit of housekeeping before you start cutting angles. Use either compressed air (using an air compressor with an air nozzle or just a can of compressed air) to blow away sawdust. Then use a clean cotton cloth to wipe down the saw. This will remove any remaining sawdust or pitch build-up.
2. Check the Blade
Be sure your blade edges are still sharp. Also, hold the blade up and eye it to be sure it’s not warped or skewed in any way.
3. Check the Table
A table that’s out of alignment will throw off the cuts your saw will make. Use a level to be sure your working surface is even.
4. Check the Fence
A miter saw’s fence is the supporting back edge that cradles the materials you’re cutting, keeping them in a fixed position as you cut. Use a straight edge or a square to be sure the fence is square. If it’s not, loosen the screws holding it in place and adjust the fence until it’s squared, and then tighten the fence back into place.
5. Check the Angle
Now you want to be sure that your 0-degree saw angle is square with your fence, so set the blade at 0 degrees. Put a square on the table, resting one edge against the fence. Lower the saw to the lowest position and slide the square to the blade’s edge. (You might have to raise the blade guard to do this.) Now your square should rest tightly against the fence on one side and the blade on the other. If you have any gaps, then you’ll need to adjust the miter so the blade and the fence are square with each other. Saws can vary, so you may need to look at your instruction manual to find out how to do this.
6. Adjust the Saw
The specifics of adjusting a miter saw to the position you desire will vary depending on the brand of saw that you have, but generally, miter saws are adjusted by using a knob and a lever in front of the saw. These will swivel the saw into the position needed for the miter angle you want to make. Obviously, for a 45-degree cut, you’ll want the saw blade to be at a 45-degree angle.
And that wraps up our setup. Now we're ready to start cutting.
Position the Wood
Put the wood you want to cut against the fence. With scrap wood, you don’t need to worry about proper placement of the cut. But when you’re cutting for a project, be sure you’ve marked the spot where your cut should go. And follow the old adage, “Measure twice, cut once.” My husband actually measures three times just to be sure.
When marking the wood for cuts, extend the mark completely across the wood. With the saw OFF, lower the blade until it touches the wood to be sure the blade is in alignment with your mark. Adjust the board if you need to so the mark and blade line up.
When you’re learning how to use a miter saw to make 45-degree cuts, or anytime you’re using a saw, you want to do everything possible to stay safe. Most power saw accidents result from carelessness. Follow these tips to avoid injuries.
- Be sure you’re wearing safety goggles and ear protection when you use your miter saw.
- If you’re working with treated lumber, wear gloves and a dust mask.
- Be sure you’re not wearing any loose clothing like an open jacket that could get caught in the saw. If you have long hair, tie it back. Don’t wear dangling jewelry of any kind while using a saw.
- Be sure you’ve set up your wood so any long pieces are supported. If wood is dangling in mid-air, it can snap and get thrown.
- To avoid cutting yourself, be super-aware of your body at all times. Keep your feet firmly planted, and never cross your arms. If you have experience using a saw but haven’t made 45-degree cuts before, remember that the saw will now be at a different angle than you’re used to. Position your hands on the wood with this new in mind. Keep your hands well away from the saw blade.
Turn on the Saw
Be sure you allow your saw to get to full speed before you do any cutting.
Make the Cut
Holding the wood in place with one hand, use the other hand to bring the saw down slowly and evenly and run the blade through the wood. Don’t push down on the blade. The saw will do the work. You’re just a guide. Once the board is cut completely through, turn off the saw blade and wait for the blade to stop completely before you raise the blade up away from the wood.
To be sure you’re getting an accurate 45-degree cut, repeat the above step and make a second cut on another piece of scrap wood. Now check how the edges of the two sawed pieces fit together. If they don’t match up, you’ll need to repeat the saw preparation steps to be sure your blade is square. If they match up well, and your cut looks smooth, you can now do your cuts on your project wood.
And there you have it. You now know how to make a 45-degree cut with a miter saw. You can also make cuts at other angles by adjusting the blade position on your saw. Remember that, as with all things, practice makes perfect. The more cuts you make with your miter saw, the more even and accurate your project cuts will be.