Porter-Cable Model 548 - Manual (Page 11)

11
One of the distinctive and important features of the Porter-Cable bayonet
saw is the ability to start the cut (in wood only) within an area without making
drilled holes first. This is especially important when making cut-outs for
electric outlets in finished walls, openings in cabinet tops for sinks and
openings for plumbing fixtures.
First, measure the area to be cut out and mark it clearly with a pencil, chalk
or scriber. Choose a convenient starting point and hold the bayonet saw
over the point and inside the line of waste. Tip the machine forward until the
front edge of the base rests firmly on the surface of the material with the tip
of the blade clear of the work surface, as shown in Fig. 4. Turn motor “ON”
and slowly lower the back of the machine allowing blade to bite into surface
of work. Do not move the machine forward until the base is fully seated on
the surface of the work. Now, guide the cutting along the inside of the
marked area. If sharp corners are desired cut right up to the corner of the
marked edge. Stop and back up just a bit, start the turn and cut along the
side. Do the same at each corner until you end up where you started. Then,
go back and cut into each corner from the opposite direction. The base of
the machine is wide enough so you will have a solid guiding surface on
either side of the cut.
USING THE JIG SAW
First, secure the material in a bench vise or with clamps to the work table.
This is especially important when sawing small pieces or thin material. As
the work progresses in scroll or curved cut-out pieces, the material can be
re-adjusted to accommodate the movement of the saw. If the work is large
enough, it may be held only by hand across saw horses or some other rigid
support. The saw cuts freely with only light forward feed pressure on the
tool. Forcing the saw will not cause it to cut faster. Be careful not to twist the
saw while making the cut. This will cause blade breakage. To start the cut,
secure the work, mark the line of cut clearly, place forward edge of saw base
on edge of the material, start motor and when motor is up to desired speed,
move blade into the work.
NOTE: Because of the variable speed feature, trial cuts at varying
speeds should be made on scrap material to determine the cutting
speed for the most desirable results.
Fig.` 4