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Cutting molding with a miter saw isn't as difficult as it seems, especially if you follow our advice. If you're new to using a miter saw, one of the most useful DIY skills to possess, is to be able to correctly cut a piece of trim using a miter saw.
In this article you’ll learn the right way to accurately cut and fit a piece of trim for both windows and doors, baseboard trim, and even crown molding. We'll touch on everything from miter cuts, shaving miters, coping baseboards trim and much more.
If you follow this guide, the piece of trim you'll be cutting will fit right every time if you adjust your cut to the precise angle of degrees in which your corner piece molding will be installed.
Most of what you'll need for installing molding successfully is decent compound miter saw, a hammer or nail gun, a measuring tape and or combination square, and of course, some trim molding. We'll cover this more in detail later, but keep in mind, some hardware and tools will be required, if you want to sign your name to this.
If you've got everything you need, you're now ready to cut and fit any piece of trim by simply following these tips below.
Before you get to work, make sure you have everything you need. If you’re new to this, you might forget some of the things you require, so we made a bucket list of necessary items. You don’t need a lot of materials, so let’s start by covering that first.
Materials: You’ll need trim, glue, shims, brad nails, and molding.
Now, the list of tools you need is a little bigger, so here’s a neat bullet-point list, plus some additional safety tips:
While this part of the article might be the most overlooked, when it comes to operating power tools, especially saws, taking a few moments to consider the task at hand should really be paramount. While health & safety is normally and afterthought for most DIY enthusiasts, professional contractors take it very seriously, hence the reason majority of injuries happen at home, not at work.
So be a professional (even if you're not) and err on the side of caution by being aware of the tools you are working with at all times. Always utilize a miter saw while working off of a stable base or use a miter saw stand if you have access to one. Keep your base station clear of any off cuts left behind, and stack the trim you're working with neatly to prevent a potential tripping hazard.
Sounds like common knowledge, right? Well, that's because it is.
Note, if you're in an area where the public or even your family members can access, a basic work in progress sign could be useful, too.
So now you’re ready to break out the big guns and effortlessly make the cuts necessary to install the perfect piece of trim. Since there are many different techniques depending on the trim, we’ll separate the processes to cut and fit trim into separate sections for better clarity and understanding.
The one sign that indicates that your trim molding isn't installed to highest of standards, is a defective looking corner piece of trim. While optimizing your trim molding to reveal elegant looking angles and pristine corner pieces might seem daunting, you'll get the hang of it with the right knowledge and tactics.
You should be looking to cut majority of your angles for interior trim are 90° and 135° degrees. If it's your standard inside corner at 90°, you should cut each piece of trim at a 45° angle so that when the two pieces of trim form a corner piece, you have yourself 90° angle.
So your first step to make this 90° corner cut is to set the angle of your miter saw to 45° and cut both bits of trim accordingly. Now that you're developing a base understanding of angles and there relevancy regarding miter saws, lets dive a little deeper with some more complex tips and tricks.
Sometimes, when you cut miters for a pair of trim moldings you’ll notice they aren’t fitting well. This is quite common, and it has nothing to do with your miter saw or the way you’re operating it. Fact is, most walls aren't a true 90 degree right angle. The secret to fitting your trim flat against the wall to display the perfect looking corner piece of trim, is to shave the miter cut so the trim can fit the off angel better.
This can be done the simple way, just by slightly altering the angle of your saw and molding pair. In fact, this method is simple for those saws which allow for these micro-adjustments, and expert carpenters, of course.
Another way, which is more novice-friendly, is to put a shim against the fence of your miter saw. This will alter the angle slightly, just enough to make a fitting cut. If you place the shim further away from the miter saw blade, it will allow small adjustments. Alternatively, if you position it closer, you can make big adjustments.
Always keep in mind that you need to cut both pieces identically so they can fit the corner angle correctly.
This sounds great and easy in theory, now lets do it in practice step by step following these important tips:
Also, remember that you need to trim both sides of the miter identically. Use the same steps as before, gently shaving off thin pieces.
Window and door jambs don’t always fit with the wall. If a jamb is poking out, you can nail the trim to it, then put a shim in between the drywall and the trim, finally nailing the trim to the wall. If you’re worried about the gap, just use some paint and caulk to hide it.
Inset jambs require a different solution. In this case, you need to remove some drywall in order to extend the trim to the jamb and wall tightly. This isn’t all. Even if you use a 45-degree miter, it won’t fit. The molding needs to be tilted down so it can meet the jamb.
You need to tilt the trim to your miter box, replicating the angle of it resting against a wall. Only then can you use the regular 45-degree miter cuts.
Follow these instructions and tips and you'll be left with exquisite looking trim:
You won’t perfect the art of using a miter saw to cut trim until you’ve done some baseboard coping. This is actually more efficient than mitering the inside corners. Coping tall baseboards is hard if you use just a coping saw, miter saws are actually better at this.
Without much theory crafting, follow these detailed steps and creative tips to cope baseboard perfectly:
Coping corners to a ‘T’ doesn’t make a difference if you have floors or walls that are uneven.
Follow these instructions and useful tips for closings gaps on inside corners:
Outside corners are also difficult to fit. You need to make precise baseboard markings instead of being overly reliant on measurements.
Follow these steps for cutting trim effectively utilizing a miter saw on the outside corners with these insightful tips:
Trims can often have dead ends, on chair rails, window aprons, etc. Sure, you can chop them up and use some nails, but that just doesn’t look right. You can use a better way, giving your trim that final perfect touch.
Follow the steps for these tips fix dead ends on trim:
When you fix a dead end like this, your trim moldings will exhibit a perfect looking finish, showcasing your master craftsmanship skills courtesy of every superb cut and well crafted corner of your project.
There you have it. We hope this article covered everything you need to know to cut and install trim with a miter saw, including dead ends, outside corners, inner corners, coping baseboard, shimming and shaving miters and trimming jambs.
Miter saws are extremely safe if you’re careful and you know what you’re doing. Never move your fingers too close to the blade; keep them at least six inches away and don't cross your arms over when maneuvering the saw. Before you commence your trim project, equip yourself by purchasing all the necessary tools and materials.
Owning a high quality compound miter saw will go a long way in developing your skills as a craftsman and prove to be a great investment for your workshop.
My name is Michael McDonnell, and I’m the creator of The Tool Scout. I’m a mechanical engineer by trade with over 20 years of experience in the construction industry. I started The Tool Scout because I love talking about everything DIY related and figured I could help others with the decision-making process when it comes to selecting the right tools for the right job.
Apart from being a blue-collar kinda guy on a relatively noble quest to help others, I’m also a serial entrepreneur and an obvious lifelong Lakers fan. 🏀