After the saw has been jointed and set, adjust it in the clamp for filing. Place it as low in the clamp as the position chosen for the file will permit. The point of the saw should be to the left. This position gives to most persons the best view of the teeth while finishing after the saw has been turned. If. however, experience teaches that the teeth to be finished can be seen better from the other side, file to the right of the clamp first.

The clamp should then be placed in the best light obtainable and at the height that will give the operator the best view of the teeth. This will vary with different persons. A little below the armpits is found to be right by a good many filers.

Hold the file firmly with the point somewhat elevated at the pitch and bevel decided on.

The filing should be done with the point of the file travelling in the direction of the point of the. saw cutting the edges of both teeth. This gives the correct form to the teeth and steadies the file, which should be lifted slightly on the return stroke.

The reason for filing towards the point of the saw is that the file moves in the direction of the setting and of the cutting edge of the teeth, and there will thus be less vibration. If on the contrary the filing is done towards the heel of the saw the file is cutting against the setting and against the cutting edge of the tool, and the vibration will be sufficient to take the points off the teeth and the cutting edge will be rounded as well as full of fine notches made by the teeth of the file.

If those who advocate filing in the opposite direction (that is, toward the heel of the saw) will use a magnifying glass in comparing teeth so filed with those filed towards the point, the reason for filing as above recommended will be obvious.

In filing towards the point of the saw there will be a slight feather-edge on the tooth which may be taken off by running a straight oilstone lightly over the sides of the saw. If this is not done, however, the feather-edge will soon disappear. The feather-edge, by the way, is the only argument for filing towards the heel.

File every other tooth. Pile back on the widest teeth as shown by the size of their points. Make the points on each side of the file the same size, taking care to leave enough of the flat produced by the jointer to be seen. See that the cutting edge of each tooth is sharp before leaving it.

It is well during the progress of the work to occasionally put the file back to the first tooth filed to make sure that the pitch and bevel originally assumed have been maintained. This certainly should be done when it has been necessary to shift the saw in the clamp or after laying the file down for any cause.

After filing one side of the saw in the way described, turn the saw " end for end " and file the other side in the same manner, but the point of the teeth must be watched very carefully, for even a small fraction of a stroke of the file, after the tooth has been brought to a point, will reduce its length.

The glint on the point of the tooth, i.e., the reflection on the flattened end produced by the jointing, is the only guide for its length, and after that has been lost further filing will be simply guesswork.

If after taking the saw from the clamp the work is not satisfactory, run the jointer very lightly over the ends of the teeth, and after returning the saw to the clamp touch them up with the file.

Rip Or Slitting Saws

The teeth of rip saws are a series of chisels following one after the other as they cut their way through the material. The teeth should be filed square across, and kept uniform in length, pitch, and set. Piling every other tooth enables one to file with the setting, the tooth set which is toward the workman being touched only slightly. Filing half the teeth from one side and then changing end before completing the operation will tend to produce uniformity in the teeth and make the saw less liable to " run."

Suggestions

A cut off saw with its point rounded is not so likely to " catch " when starting the kerf or cut, thus preventing the bending of the saw and splintering the wood. A cut can also be more easily started in the centre of a plank without boring, etc., for it, see Fig. 190.

Omitting to set one or more teeth opposite to each other at some point along the saw, or bending them a little inward will clear the kerf when the regular teeth or those fuly set do not clear it fast enough.

Fig. 190.

The teeth of a rip saw are usually made finer at its point than further back so that the saw will not be " held up " at its start.

Filing the teeth fleaming at the point and for a short distance back like those of a cut-off saw will reduce the danger of a " hold up " and this part of the saw can be used to cut through knots if encountered on the way.

Saws for coarse work, especially those that may be used to cut diagonally across the grain as for framing rafters, stair carriages, etc., should be filed with considerable fleam, with the cutting edge about at right angles to the line of the teeth.

A compass or key-hole saw should have less hook and more fleam than a rip or slitting saw, but more set than a cut-off saw.