Crosscut Saw Manual

Filing the Saw, continued

Raker Fitting, continued

Fitting Swaged Rakers

Swaging is forming the leading edge of the raker into a curve so it more efficiently picks up the shaving. It is done by striking a prepared raker tip on the inside face with a hammer to bend the tip outward in a smooth curve.

Tools necessary are a pin gauge, 8- to 16-ounce hammer for swaging (16-ounce hammer preferred), raker gauge, 6-inch, slim-taper file with "safe" corners, and a 6-inch, mill-bastard file. A pin gauge generally is part of a combination saw-filing tool.

I know of no hammers specifically designed for swaging. A swaging hammer should have a face small enough to allow you to strike the raker tip with the center of the hammer face. The best substitute for a swaging hammer appears to be a tinner's riveting hammer. A swaging hammer should weigh about 16 ounces. A lighter (8-ounce) hammer can be used, but a 1-pound hammer is easier to use.

Tools needed to fit swaged rakers

Combination saw-filing tool and pin gauge

Swaging hammers

To Prepare the Raker--File it approximately to the shape shown at right with the slim-taper file. The exact shape depends on whether the raker is straight or if it has been swaged before. The objective is to shape the tip so it can be bent without breaking but retain enough thickness to prevent bending during use. The cutting angle should be between 30 and 40 degrees.

Preparing a raker

The raker is now ready to be "swaged to the pin." This means bending the raker by striking the inside face of the raker tip with a hammer until the tip just clears a preset screw (called a pin) on a combination saw tool.

The pin is adjusted so the swaged raker is 0.002 to 0.003 inch higher than the finished raker depth. This is done by first filing a raker to depth using the raker gauge (which has already been set using methods described previously). Next, place the pin gauge over the raker and adjust the pin (screw) depth so a 0.002- or 0.003-inch feeler gauge will just pass between the raker tip and the pin. Check the clearance again after tightening the locknut.

Gauging rakers with the pin gauge on the combination saw tool

To Swage a Raker--Strike the raker tip a square blow and check the height with the pin gauge. If it is still too high, continue alternately swaging and checking until the raker tooth just clears the pin. Keep an eye on the shape of the bend. The outside face of the raker should bend in a smooth arc. A kinked raker tip will be difficult to swage next time the saw is filed, and it will quite possibly break. If the tip begins to kink, the hammer probably is being used too high on the tip. If it won't bend, the tip may be too thick or the hammer is being used too low on the tip. Often in the case of a new saw or a used saw with straight rakers, it will be necessary to partially swage the tip. Thin the tip with the file and continue swaging.

There is no pat answer to the question: "At what angle is the raker struck?" This will vary with the shape of the raker tip and must be learned from experience. Keep an eye on the desired swage shape. Knowing where to strike the tip will come with experience.

Striking the inside face of the raker tip with a hammer

Some saws are so hard and consequently brittle that there is a possibility of breaking raker tips when swaging. If a saw is so hard that a fairly new file keeps slipping while the filer is shaping the raker gullets, or if a raker actually breaks when being swaged, the rakers should be tempered.

To temper the raker, polish one side of each raker until it is shiny. Place the saw in a vise. Heat the top three-fourths of the tooth uniformly using a propane torch. As it gets hotter, the color will go from light straw to brown, to deep purple, to dark blue, to light blue, to a light yellow color. Opinions differ on how far to temper the rakers (or to heat them to what color). A compromise seems to be between light blue and the second yellow. A suggestion would be to first temper to light blue and if trouble is still experienced, temper again to the second light yellow. Don't heat into the body of the saw because it may cause the saw to warp. Be very careful about playing the torch flame on the raker tips--they heat very fast, making them extremely easy to overheat. The result is a soft raker that will bend in hardwood and will not hold an edge.

Once the rakers are "swaged to the pin," the tips are dressed on the outside face. To dress the swaged tip, a 6-inch, slim taper file with safe corners is passed lightly across the under edge of the swage to square it up and establish the rake angle. It is most important not to nick the raker with the edge of a file. A nick can cause the tip to break off during swaging or while the saw is being used. This is the reason for the ground safe corners on the dressing file. After dressing the outside face and rake angle, joint exactly as with the straight-style raker. As with straight rakers, a trial depth of 0.012 inch is good for average conditions.

The last step is to dress the sides of the rakers. The swaging process often widens the raker at the tip. This can be corrected by holding a 6-inch mill-bastard file flat against the raker and saw and making one or two light vertical strokes.

Dressing a raker

Repairing Bent Rakers and Cutter Teeth

To check for bent rakers, make up a spider (set gauge) for zero clearance on an unbent raker. A bent raker can be found easily by using the spider in the same manner as for checking cutter tooth set (see Setting).

To straighten a bent raker, the concave side of the raker is placed on an anvil and hammered until the tooth is straight. Badly bent cutter teeth could be straightened the same way.

Broken Raker Tip

A broken raker tip allows the other tip on the raker to bite too deeply on the cutting stroke, causing the saw to catch just as it does with a long raker. File the unbroken tip shorter, about 0.005 inch initially. If it still catches, continue filing.