, tenon, and cross-pin measurements are given in Table 3.
In the case of round mortise
and tenon joints, however, cross-pins might actually reduce the bending moment capacity of the joints since they could induce parallel to grain shear failures in the tenons.
no splitting of mortise
or tenon members was observed).
Given the above results, the maximum possible practical distance was maintained between mortises
for side rails and the mortises
for front and back rails in the chair shown in Figure 1, in most instances, a spacing of 1-3/8 inches.
were drilled in the members with 2-1/16-inch-diameter Forstner bits.
the joint behaved as a conventional mortise
and tenon joint.
Knee braces are important structural elements in timber bents constructed with round mortise
and tenon joints, as shown in Figure 1, not only because they provide resistance to horizontal wind loads (Karlsen 1967) but also because they can improve distribution of forces in the frame and permit the use of wider spans.
Front and back rail tenons were centered on the ends of the rails so that the corresponding leg mortises
could be located a slightly greater distance from the end of the leg (Fig.
Commercially available loose tenon systems exist such that the mortises
can be made with simple drilling or routing operations.
These specimens had 2-inch diameter mortises
and end-distances of 1.
were drilled in the posts with a 19/32-inch (15 mm) drill bit so that a tight shrink-fit could be obtained when the tenons were inserted in the holes.
Because most often the cross pins failed rather than the tenons, the potential withdrawal resistances of the tenons themselves, or, the walls of the mortises
, whichever is greater, were not determined.