of the rail (B) must
be straight with the side of the stile. If the work is done by machinery
it results in accuracy unattainable in hand work.

[Illustration: _Fig. 208._]

TRUE MORTISE WORK.--The essense of good joining work is the ability to
sink the chisel true with the side of the member. More uneven work is
produced by haste than by inability. The tendency of all beginners is
to strike the chisel too hard, in order the more quickly to get down to
the bottom of the mortise. Hence, bad work follows.

STEPS IN CUTTING MORTISES.--Examine Fig. 208, which, for convenience,
gives six successive steps in making the mortise. The marks _a_, _b_
designate the limits, or the length, of the mortise. The chisel (C) is
not started at the marking line (A), but at least an eighth of an inch
from it. The first cut, as at B, gives a starting point for the next cut
or placement of the chisel. When the second cut (B) has thus been made,
the chisel should be turned around, as in dotted line _d_, position C,
thereby making a finish cut down to the bottom of the mortise, line _e_,
so that when the fourth cut has been made along line _f_, we are ready
for the fifth cut, position C; then the sixth cut, position D, which
leaves the mortise as shown at E. Then turn the chisel to the position
shown at F, and cut down the last end of the mortise square, as shown in
G, and clean out the mortise well before making the finishing cuts on
the marking lines (_a_, _b_). The particular reason for cleaning out the
mortise before making the finish cuts is, that the corners of the
mortise are used as fulcrums for the chisels, and the eighth of an inch
stock still remaining protects the corners.

THINGS TO AVOID IN MORTISING.--You must be careful to refrain from
undercutting as your chisel goes down at the lines _a_, _b_, because if
you commit this error you will make a bad joint.

As much care should be exercised in producing the tenon, although the
most common error is apt to occur in making the shoulder. This should be
a trifle undercut.

[Illustration: _Fig. 209._]

See the lines (A, Fig. 209), which illustrate this.

LAP-AND-BUTT JOINT.--The lap-and-butt is the form of uniting members
which is most generally used to splice together timbers, where they join
each other end to end.

[Illustration: _Fig. 210._]

Bolts are used to secure the laps.

But the lap-and-butt form is also used in doors and in other cabinet
work. It is of great serv