When you look at the choices available in tenon and dovetail saws, you discover that they look alike in the catalog or display case. When you consider the joinery that each tool is intended to create, the subtle differences in each saw begin to make more sense.
The Backsaw Family
Both the dovetail and tenon saws are from the larger family of backsaws, which have a brass or steel stiffener mounted along the back of the blade. These tools are used to make perfectly straight cuts with high precision; the back does not allow the blade to flex when it is pushed or pulled on the cut stroke. The blade is usually rectangular or slightly tapered to ensure that the cut depth remains uniform.
The tenon saw is the most common form of the backsaw. It is intended to create the cheeks and shoulders of a tenon joint on the end of a piece of lumber. In order for this joint to fit snugly, it is important that the saw create straight and square cuts to a close tolerance. The teeth on a tenon saw are relatively fine, with14 to 20 teeth per inch (TPI). Compared to the dovetail saw, the tenon saw has a taller, heavier blade to make the 1- or 2-inch deep cuts needed for the joint.
The teeth on a tenon saw are ground for making either a crosscut or a rip cut. The crosscut saw is used to cut the shoulders of the joint, which generally run perpendicular to the grain of the wood. Rip cuts, in contrast, are made parallel to the direction of the grain. The fine teeth of saws in the 20 TPI range make it likely that many woodworkers will find one saw suitable for both cuts.
The dovetail saw is designed to make rip cuts with a narrow kerf and high precision. Similar to the design of other backsaws, it has a brass back that keeps the thin blade rigid during the cut. The blade is not as tall as the tenon cutting blade because the joint is only as deep as the thickness of the lumber being cut. The dovetail joint is made with a rip cut, so a good dovetail saw will be optimized to this task. An ideal cut from this saw is balanced between the speed and the finish of the cut.
Choosing a Grip
Because dovetails and tenons must be precise, square and plumb, it is important to take into account the grip style when choosing a new saw. The totes of these saws are made in three forms: full handle, pistol ground and barrel. Some woodworkers prefer a traditional tote that surrounds the hand but limits the finger positions that can be used to guide the saw. The pistol or barrel grip provide more options in the way the finger or thumb can be pointed, helping to keep the cut in line during use.
Buying a Saw
An unlimited budget will enable you to have a saw for each specific cut you want to make. If money is tight, you can start by purchasing one quality tenon saw to make both joints. Later, when your skills improve, you can add a specialized dovetail saw to your tool chest.