Handsaws (aka, hand saws) have been around in one form or another for thousands of years. Nowadays, handsaws have been largely supplanted by power saws but a quality handsaw with a properly sharpened blade can still work wonders (plus you’ll get a good workout using it).
A typical handsaw has a wooden or plastic handle that comfortably fits the hand and a wide, tapering blade that cuts on the push stroke. For general purpose carpentry, a good general purpose saw is one with a blade about 2 feet long and 8 teeth per inch.
There are two basic types of handsaws: rip saws and crosscut saws. A rip saw has fewer teeth per inch, a zero to positive rake, wider set, tooth angle closer to 90 degrees, and a relatively deep gullet behind each tooth which helps in transporting sawdust out of the cut. A crosscut saw has more teeth per inch, a zero to negative rake, narrower set, and a more beveled cutting edge (tooth angle). The rake is the angle of the tooth relative to the body of the blade. A zero rake means the teeth are perpendicular to the body of the saw, negative means they are angled slightly backwards.
Rip Saws have lower point sizes (fewer tpi), zero to positive rake angle (more aggressive cuts), wider set (teeth bent out further away from the blade), and higher tooth angles (closer to 90°). Plows through wood quickly. Can cause severe tear out across the grain.
To make a cross cut, mark the desired cut line and start the cut by pulling lightly on the saw a few times using your thumb knuckle against the blade body to align the cut. Once the cut is started, complete using full even strokes with the saw at about a 45 degree angle. As the cut nears completion, ease up on the stroke length.
Rip cuts, which go in the direction of the wood grain, are cut in a similar manner as cross cuts except that the saw strokes are made at a 60 degree angle. Depending on the length of the cut and how ornery the wood is, a wedge made need to be placed in the cut to prevent the wood from binding against the saw.
It’s not hard to figure out when a handsaw needs sharpening: it will cut sluggishly and require extra effort to push the blade through the wood. It will also be difficult to cut straight.