First Class Sawing
This type of sawing is best for parts of the joint that will be visible on the finished piece, such as the shoulder cut on a tenon or half-lap joint. It requires a couple of extra steps, but the results are worth it.
First mark your cut-line with a marking knife on all surfaces that will be cut. Then take a wide chisel and place the tool’s edge into your knife line with the bevel facing the waste. Rap the handle of the chisel to drive it into the knife line all around the joint.
Remove the chisel and then pare away a wedge-shaped piece of wood on the waste side, working up to your now-widened knife line. The second chisel cut must be deep enough so that the set of your saw’s teeth is below the face of your work.
Secure your work to the bench. Place your saw into the chiseled notch and make the cut. By using a chisel to define the kerf of your saw, you eliminate the common problem of the saw’s teeth tearing at the surface of your work.
Top: Widen all knife lines: Place your chisel’s edge into your knife line and tap the handle to drive the edge into your work, widening the “V” left by your knife.
Bottom left: Pare all around: With the bevel of your chisel facing up, pare a wedge-shaped piece of waste away on the waste side of the joint.
Bottom right: Sawing is simpler: The chiseled notch guides your saw and eliminates any torn grain from the face of your work.
— Christopher Schwarz