ke a chisel, and bores away the
superfluous timber, whilst the pressure exerted on the chisel causes the
corners to be cut away dead square. A mortise 3/8 in. square by 6 ins. in
depth may thus be cut. The portion marked A is the shank of the chisel
(Fig. 140), where it is fixed into the body of the machine, and the hole
at E allows the boring bit to free itself.
[Illustration: Fig. 141.--Method of Fitting an Interior Table Leg.]
[Illustration: Fig. 142.--Haunched Tenon for Skylight or Garden Frame.]
[Illustration: Fig 143.--Long and Short Shouldered Tenon.]
Fig. 141 indicates the method of fixing an interior leg to a table having
a circular or straight top rail. The inlaid leg in this case is
stump-tenoned into the top rail, and the inlaid portion of the leg is
allowed to run through the rail, thus giving continuity of design.
Fig. 142 shows the application of the haunched tenon (Fig. 135) to the
making of a skylight or garden frame. In this and similar cases the side
rails are rebated as shown in the section, and the bottom rail is thinner
than the side rails to allow the glass to finish level upon it.
LONG AND SHORT SHOULDERED JOINT.--Fig. 143 shows a haunched mortise and
tenon joint having a long and short shoulder. This is a fairly common
joint in framed partitions for offices, framing for greenhouses, tool
sheds, etc., and is a frequent source of annoyance to the amateur. It is
necessary to use this joint when both the stiles and uprights are
rebated, and it calls for accurate marking out and great care in the
making.
[Illustration: Fig. 144.--Joint for Fencing.]
[Illustration: Fig. 145.--Example of Faulty Tenon.]
Fig. 144 shows the upright and rails of common garden or field fencing.
The tenons are bevelled to fit and wedge each other in the mortise. The
illustration gives both cross rails as shouldered, but in many cases
shoulders are omitted when the rails are not thick enough to carry them.
Fig. 145 indicates faulty methods of working a tenon. At A the saw has
been allowed to run too far when cutting the shoulder, thus greatly
weakening the tenon. At B faulty sawing has again occurred, and to remedy
this defect the worker has resorted to paring the shoulder with a chisel.
Had the chisel been used vertically an undercut shoulder (as at B) would
not have occurred. The trouble now is that the slightest amount of
shrinkage in the width of the stile will show an open joint. The result
will be th
|