Miter saws and chop saws are often confused, partly because they typically have the same appearance. Miter saw is the term used most often in woodworking. Chop saw is used more often in production shops or building sites. Both saws are used in a similar manner, but distinct capabilities make the two saws different from each other.
The axis is the defining difference between miter saws and chop saws. The blade on a chop saw remains perpendicular to the table and is only capable of performing 90-degree cuts. The axis or shaft of a miter saw swivels, allowing the blade to cut angles. Confusion between the two arises because a miter saw performs the same duties as a chop saw when its blade is locked at 90 degrees. This means that the miter saw can be used as a chop saw. However the chop saw can never be used as a miter saw because the shaft and blade always remain at 90 degrees.
More confusion arises because there are two types of miter saws -- the standard miter saw and the compound miter saw. The blade of a standard miter saw stays vertical at 90 degrees to the wood when cutting angles. The blade of a compound miter saw swivels like a standard miter saw, but it also tilts sideways to cut compound angles. The blade enters the wood not only angled, but also tilted to cut a bevel. The compound miter saw is used more by professional woodworkers, but from all outward appearances looks like a standard miter saw or chop saw. Chop saws and miter saws are also sometimes referred to as a drop saw. The blade enters the wood from above. Another type of saw -- the radial arm saw -- which can also be used as a miter saw, slides across the wood horizontally and should not be confused with either the chop saw or the miter saw.
David and Goliath
Commercial chop saws are operated by a foot or knee switch with hydraulics. Both hands feed lumber through the saw from side to side. This type of saw is fast and should only be operated by professionals. For home building or woodworking, the bench-mounted chop saw and miter saw are operated by hand. The chop saw typically has a bigger motor and blade than a miter saw. It's used to cut two-by-fours, two-by-six studs and larger pieces of lumber at 90 degrees. The miter saw is commonly used to cut smaller pieces of molding and trim at angles. It's physically smaller, with a finer blade to make cleaner cuts for finished wood projects.
One type of miter saw is never confused with the chop saw. It has no motor; only a small hand-operated blade inside a wooden box without a top. The side of the box is slotted at standard angles. The hand-operated or manual miter saw cuts simple angles, including the 90-degree angle, on smaller pieces of molding and trim. It's slower than a power miter saw, but is capable of cutting clean, accurate angles. It's affordable and easy to use.
If you're going into woodworking, the miter saw is the best option. If you're going into home building -- more particularly, framing -- the chop saw is more capable thanks to its bigger cutting capacity. Typically, for home building you'll need both types of saws, the chop saw for the big stuff and the standard miter saw for finish work. If you want to take the finish work to the next level or go into fine woodworking, the compound miter saw is the best option.