The tongue
of the T-square should be approximately 3 feet long; the hinged
block should be approximately 12 inch long which provides a solid
bearing surface. Both pieces should be cut from Select grade wood;
3/4-inch thickness is adequate, although you may want to consider
5/4-inch material. Or, you can cut both pieces from scrap wood,
if you have a square-cutting table saw.It is
recommended that you seal the wood with a coat or two of shellac,
sanding the surface between coats.
To use
the adjustable straightedge, clamp the material to be shaped to
a work surface. Then
clamp the hinged block to the material and set the angle you want.
Clamp the end of the tongue. Pad the clamps.
MAKING
A GUIDE BOX:
To cut stopped grooves or parallel blind grooves, here's a guide
box you can make. Use Select stock, with half-lap joints at the
corners. Glue and nail the joints. The inside edges of the box must
be square and smooth. The side rails of the box must be absolutely
parallel to each other and spaced to fit the outer edge of the ring
base of your router.
If you
are making a blind and stopped cut, the measurement between the
two end pieces must be equal to the length of the cut plus the diameter
of the router ring less the diameter of the router bit.
If you
make the box extra long, you can mark the "start" and "stop" lines
for the router on the rails of the box. But before you make any
cuts in good material, test the box and the cuts you want on scrap
wood. Then seal the box with two coats of shellac.
