th of the lower piece, called Y, on one arris, and
from this point lay off on this arris half the width of the upper
piece, X. From this point square across Y with the knife and
try-square. Lay X again in its place, exactly along the line just
scored. Then mark with the knife on Y the width of X, which may then
be removed and the second line squared across Y. From these two lines
square across both edges of Y to approximately one-half the thickness.
Now turn X face down, lay Y on it, and mark it in the same way as Y.
Set the gage at one-half the thickness of the pieces, and gage between
the lines on the edges, taking care to hold the head of the gage
against the marked faces. Then even if one piece is gaged so as to
be cut a little too deep, the other will be gaged so as to be cut
proportionately less, and the joint will fit.

Cut a slight triangular groove on the waste side of the knife-marks,
Fig. 91, p. 66, saw accurately to the gaged lines, and chisel out the
waste as in a dado, see Figs. 70 and 71, p. 56.

The bottom of the dado thus cut should be flat so as to afford surface
for gluing. When well made, a cross-lap joint does not need to be
pounded together but will fit tight under pressure of the hands.

_No. 15. A middle-lap joint or halved tee_, Fig. 265, is made in the
same way as a cross-lap joint, but one member projects from the joint
in only one direction, it is used to join stretchers to rails as in
floor timbers.

_No. 16. An end-lap joint_, Fig. 265, is made in the same way as a
cross-lap joint except that the joint is at the end of both members.
It is used at the corners of sills and plates, also sometimes in
chair-seats.

To make an end-lap joint, place the members in their relative
positions, faces up, and mark plainly. Mark carefully on each member
the inside corner, allowing the end of each member slightly (1/16")
to overlap the other. Square across at these points with a sharp knife
point, on the under side of the upper member, and on the upper side of
the lower member. Now proceed as in the cross-lap joint, except
that the gaged line runs around the end and the cutting must be done
exactly to this line.

_No. 17._ In an _end-lap joint on rabbeted pieces_, Fig. 265, the
joint must be adapted to the rabbet. The rabbet should therefore be
plowed before the joint is made. The rabbet at the end of the piece X
is cut not the entire width of the piece Y, but only the width of the
lap,--c-f=a-e. T