The whole idea of any miter saw is to be able to cut at an angle accurately. Generally speaking, this means crosscutting at an angle as that’s much more common than ripping at an angle. These saws start at cutting at 90 degrees to the lumber's face and will cut up to a 40 or 50 degree angle to either side. The ability to cut these angles accurately has made the miter saw an indispensible part of any carpenter's or woodworker's toolbox.
For many carpenters, the miter saw has all but replaced the circular saw for cutting dimensional lumber. Not only is it faster and with greater accuracy, but it’s a whole lot safer as well. There’s much less possibility of hurting yourself on a miter saw than there is with a circular saw.
The larger sliding miter saws have all but replaced the radial arm saw as the tool of choice for different types of crosscutting. About the only place where you see a radial arm saw anymore is in a cabinet shop or furniture factory. The sliding miter can do almost anything they can do and is actually much easier to work with. It is also portable whereas the radial arm saw really isn't.
Miter saws today come in a wide variety of sizes and styles, enough in fact where it almost seems like they couldn't all be called miter saws. But the one thing they all have in common is the ability to cut angles accurately, the prime purpose of a miter saw and one they all share. Of course, the more capacity the saw has, the more it will usually cost you.
Types of Miter Saws
Standard (Budget) Miter Saw
For those who need to install baseboard and casing on a home or cut picture frame molding, a standard miter saw is usually enough. There’s really no reason to pay the higher price for a more complex saw. These saws cut simple angles across the grain of the wood. A miter gauge is supplied, allowing the saw to be set to an exact angle for cutting.
Cutting with a standard miter saw is accomplished by lowering the blade into the workpiece, which is held in place on the table and against the fence. The blade and motor are mounted on a pivot, allowing them to go up and down for cutting.
Compound Miter Saw
When you step up into cutting crown molding, a standard miter saw is no longer enough. The outside corner for crown molding is a compound angle; meaning it’s cut at an angle in both the horizontal and vertical directions. To accomplish this, the saw's blade and motor need to tilt as well as swing from side to side.
Some compound miter saws are "dual bevel", meaning the motor can be swung off the vertical either to the right or left. While it’s technically possible to cut crown molding with a compound miter saw that only swings to one side, it takes a lot of mental gymnastics to get your mind around the angle you need to cut. With a compound miter, you can cut these angles much easier.
Sliding Miter Saw
The sliding miter saw has the cutter head (blade and motor) mounted on rails, allowing it to move back and forth as well as up and down. This allows for cutting of larger workpieces such as 2"x 12" dimensional lumber used for framing. While the accuracy of sliding miter saws allows them to be used for cutting large molding as well, most of the sliding action is actually used for allowing the cutting of dimensional lumber on the saw.
Sliding miter saws can either be standard miter or compound miter with a few actually dual bevel sliding compound miter saws. While these cost more, the added capacity of these saws means you can use one saw for all your crosscutting tasks, especially if you do a lot of woodworking requiring cutting angles. While a radial arm saw has the same capacity for cutting the same angle and workpiece sizes a compound sliding miter saw can, the miter saw is much easier to set up for complicated cuts than the radial arm saw is.
Manual Miter Saw
With all these powered miter saws, it would seem there’s no place left for a manual miter saw, but that is far from the truth. There are some applications, such as cutting picture frame molding or cutting extremely small workpieces (such as dowel rods) which are actually better done on a high quality manual miter saw, to avoid damaging the workpiece.
Manual miter saws range from the extreme simplicity of an old-fashioned miter box and a back saw to extremely accurate bucksaws, tensioned and mounted permanently to the miter frame. These are used almost exclusively for cutting picture frame moldings. There’s no reason for someone who uses a miter saw rarely to spend the money on a high-dollar sliding option, not when he can do everything he needs with a miter box and back saw.
Understanding How the Specifications Affect You
With such a wide range of miter saws on the market, it's extremely important to pay attention to what particular models specifications say. This, more than anything else, will determine what type of saw you need. While looking at these specifications, think of the largest workpiece you are likely to try to cut with the saw as well as the type of cuts you need to make; this will determine the size and type of miter saw you need.
Motor Size
Most power miter saws have a 15 amp motor, which provides enough power for cutting through dimensional lumber or hardwood, without bogging it down. My venerable radial arm saw only has an 11 amp motor, and I’m regularly stalling it when cutting dimensional lumber. So, for the most part, power isn’t the issue when looking at these saws, ease of use is. However, when looking at some budget models, you might find a smaller motor size. If you're planning on cutting dimensional lumber, I would avoid these saws.
Blade Size
Most miter saws are manufactured for either 10" or 12" blades, although there are some smaller ones that use 8" blades. The blade size doesn't matter much for many cutting operations, but is extremely important for cutting crown molding. If you’re planning on cutting large crown molding, you will need a saw designed for a 12" blade; this allows for cutting crown molding up to 5 1/2". In comparison, a 10" bladed miter saw will allow cutting crown moldings up to 4".
In order to cut crown moldings larger than 5 1/2", you'll need to move up to a sliding compound miter saw. Depending on the exact model you choose, many of these will cut crown moldings up to 8".
To Slide or Not to Slide
The biggest decision in determining your saw's capacity is whether or not to spend the extra money on a sliding miter saw. This depends more on the size of workpieces you intend to cut with your miter saw.
The easiest way to describe this is with three examples:
- Crosscutting or angle cutting 2" x 10" or 2'x 12" dimensional lumber
- Cutting the outside angle for crown molding larger than 5 1/2"
- Cutting the outside corner for baseboard that is more than 6" tall. With a compound sliding miter saw, you can lay the molding on its back and cut up to 12" high baseboard for that outside corner.
When looking at a miter saw, besides the basic dimensions it will cut, you want to look at the overall manufacturing quality. There are a few basic parts, which will show this better than anything else:
What to Look For
Bed and Fence Construction
As with most powered saws, the bed and fence have a lot to do with the accuracy of the cut you can make. Look at the overall quality of the castings, how well they’re finished and how big they are. A larger bed or longer fence rails drives up the cost and is a common place to try and cut corners; however, your cuts will suffer for it.
A few manufacturers offer exceptionally high fences. If you’re going to be cutting a lot of large crown molding, you want this feature. Without a high fence, it’s hard to hold the crown molding for an accurate cut. The best fences are adjustable although there are few models which have this feature.
Rollers for the Slide
The sliding mechanism consists of two polished metal tubes for rails. Manufacturers vary greatly on the types of rollers or bearings they use on those rails. Ball-bearing construction is the best, as it will roll smoothly and not wear through use.
Ease or Turning and Locking in Angles
The ease in which the table swings for setting angles says a lot about the quality of the machining done in the manufacture of the saw. Poor fit and finish shows up here, more than anywhere else. Also check the stops that are provided. Do they lock in easily and securely? For that matter, how many stops has the manufacturer provided?
While the items listed above are the most important to be looking at, you shouldn't ignore those things that will make it easier to work with your miter saw.
Other Considerations
Extensions
Table extensions add additional support for your workpiece, beyond the limits of the table itself. Considering it's not uncommon to be working with 20' long pieces when cutting molding, these can be invaluable.
Controls
How easy are the controls to access and use? The best models will have all the controls up front, so you don't have to reach past the blade to get to them. Things like handle shape can make a lot of difference when doing a lot of cutting. A "D" handle is easier to use in that case.
Lights
Many miter saws now come with laser guides for aligning the blade to your cut mark. While not necessary, they do make the job easier, especially when you’re trying to cut a lot of material quickly. Using the laser makes it much easier to be sure you’ve got the cut right.