The compound miter saw is a specialized power tool used for making crosscuts in lumber and other materials. It consists of a motor and blade combination mounted on a pivoting arm that is brought down to the material by pulling on a handle. The cuts made by the saw are precise and repeatable because the pivot point is fixed to the heavy base of the tool. The sliding compound miter saw adds depth to the myriad adjustments that are set for a cut by mounting blade and motor on rails.
Compound Miter Saws
The compound miter saw has a fixed motor-blade combination on its pivoting arm. The "compound" refers to the angle of the blade that can be adjusted on both the vertical and horizontal planes, allowing the user to make cuts with compound angles. Material is clamped to the base of the saw and the precision of the angle adjustment mechanisms makes repeated cuts that are exactly alike.
Sliding Compound Miter Saws
A sliding compound miter saw adds a rail or rails to the tool that allows the motor-blade head to slide front to back during the cut operation. This simple addition to the tool extends the width of the material the tool can cut. The sliding mechanism, however, limits the thickness of material that it can accommodate because the range of the pivot mechanism must be narrowed.
Compound miter saws have a height advantage in the greater cutting arc not limited by the sliding rails. This arc enables the saw to cut thicker material with the same size blade. This consideration is also important if the saw is going to be used to cut tall moldings for corner joints.
The rail component of the sliding compound miter saw enables the cutting head to slide along a fixed path, allowing it to cut wider materials. The compound miter saw is limited in the width that it can cut in one stroke by the size of the blade it uses. Consumer miter saws are built to use blades from eight to 15 inches in diameter, with most popular sizes being a 10- or 12-inch blade. A 10-inch compound miter saw can cut material that is two inches thick by six inches wide. A sliding miter saw with a 12-inch blade expands to handle material 4 1/2 inches thick and 12 1/2 inches wide.
Choosing a Compound Miter Saw
Either the sliding or fixed compound miter saw will make angled and square cuts as required by the craftsman. If the saw is to be used exclusively for smaller materials, the compound miter saw is a good choice for making precision cuts. The significant additional cost of the sliding compound miter saw is justified if the craftsman is going to routinely need to cut wider and taller materials that can only be accommodated by this type of tool.