DIY Compound Miter Saw Guide
This page offers an overview of the features and capabilities of a compound miter saw. For help with cutting crown molding angles and installation see Installing Crown Molding.
A compound miter saw will make many wood cutting jobs for construction framing and woodworking projects quick, accurate and easy. With miter adjustments ranging from 45 degrees to both left and right and bevel adjustments of the same, in one or both directions, just about any wood framing joint can be cut with extreme accuracy.
From the center position miter angles of 90 down to 45 degrees are possible. Using the center position as 0 degrees, all angles up to 45 degrees are possible. Add the blade bevel function and these angles can be cut in two directions at once. With this versatility the user is able to cut square joints for wall framing, mitered joints for picture frames and compound mitered joints for installing crown molding, as well as less demanding wood cutting jobs, with professional results.
Saw Capacity
The size of the blade will determine saw capacity (size of wood that can be cut). To cut small crown moldings and most other trim carpentry jobs a 10 inch compound miter saw will serve well. A 12 inch saw will cut larger crown moldings as well as most other wood projects. Use the larger saw if you foresee cutting a lot of wide boards or large timbers such as 4x4's. This may be true when cutting fence posts or wide boards for planters and similar projects. It's always better to buy the best and largest saw you can afford and grow into it rather than needing a better saw as your skills improve and projects expand.
Saw Features
Compound miter saws are equipped with a fence and table for keeping the wood stationary while cutting. The table pivots left and right to make miter cuts in both directions. Use the miter feature alone to make cuts for joining two pieces of wood to form any flat, angled joint needed for a given project. Simple projects such as shoe molding installation or building window and door frames can be done using the miter feature alone. The miter feature combined with the bevel feature allow the user to make more complicated wood joints.
Saws are available with single-bevel or double-bevel capability. A double bevel feature makes for fewer blade adjustments and allows for some angles of cut, not possible with only one bevel direction. The bevel feature in combination with the miter feature are what make cutting compound miter joints possible with this saw.
The bevel feature allows the blade to tilt either in one direction for a single-beveled saw or in both directions for a double-beveled saw. Setting the blade bevel to the proper position and then setting the miter position, allows one to cut the compound miter joints needed to join crown molding and for making frames or boxes with slanted sides as with some ornate portrait frames. See Installing Crown Molding for more about compound miter joints.
Compound miter saws feature a blade guard. This covers the saw blade when ever it is in the raised position. As the blade is lowered the guard swings up thru a spring loaded mechanism on the back, exposing the blade. Small slits in the blade guard allow the user to see the teeth as the blade is lowered. This allows one to line the blade up with the cut line before engaging the motor. When the switch is depressed the blade spins away from the user. As the blade is lowered into the work piece the guard swing up and the wood is cut. When the user raises the blade to finish the cut the guard swings down to cover the blade again.
Most saws are equipped with an automatic brake that stops the blade quickly after the switch is released. A dust bag which attaches to the rear of the saw will catch most of the sawdust produced or a vacuum hose is easily connected to the dust spout for better dust collection. A clamp accessory may be available to hold work firmly against the fence and table while cutting. These may be more trouble than they're worth for most jobs but if small pieces of wood will be cut, a clamp should be used to avoid putting hands too close to the blade.
Other accessories include an adjustable stop for making multiple cuts of the same length. An extension attachment is available for supporting long boards although a shop-made support will do the same job when attached to the workbench next to the saw. A portable saw stand may be needed to support the saw and lumber for projects away from the shop.
For storage and transporting, the saw the blade assembly is held in the down position by a lock down pin. There is a handle on top of the saw for lifting and carrying. A wrench for changing blades is included and is tucked under the saw table for storage and easy access.
After many years of use the motor brushes may need replacement as they are worn down by the spinning armature. Replacement brushes are available from the manufacturer and are easy to install. With new brushes the saw is ready for many more years of service.
Saw Blades
When possible a carbide tipped saw blade should be used with the saw. A good carbide blade will last thru years of woodworking projects. While they are a bit expensive compared to basic steel blades they last many times over and can be re-sharpened. Use a fine saw blades with about 60 or more teeth to make smooth cuts in hard woods like oak and maple. If you're cutting lumber for wall framing and similar construction projects a blade with fewer teeth, 20 to 40, will do a nice job.
