Until within a very few years stirrup irons, such as are shown in Figs. 47, 48 and 49, were used exclusively for supporting the ends of beams where a mortise and tenon joint was not desirable. The only objection to stirrup irons is the dropping of the header due to shrinkage and the fact that they are not generally carried in stock. They can easily be made, however, by any blacksmith, and a few shops make them to sell to the trade. When made to order they should cost about 4 cents per pound. In warehouses, where the ceilings are not plastered, the stirrup iron is possibly still to be preferred to the hangers above described, as with the stirrup there can be no weakening of the trimmer.

Stirrup hangers should be made from 3/8 to 5/8-inch thick and from 2 inches to 4 inches wide, according to the size and length of the timber they support. They may be made double, as shown in. Fig. 47, or single, as shown in Fig. 49. When single the end of the hanger should turn down at least 1 inches over the other side of the trimmer. As stirrup irons are ordinarily used, the end of the header is simply spiked to the trimmer to keep the latter from spreading until the floor is laid, the latter being depended upon finally to keep the trimmers from spreading, and thus permitting the header to drop.

A much better method, and one quite common in Boston, is to tie the end of the header to the trimmer by a or 7/8-inch "joint bolt" which is an ordinary square-headed bolt about 18 inches long. A hole slightly larger than the bolt is bored through the trimmer and into the end of the header. A square hole is then cut into the side of the header, as at A, Fig. 48, just large enough to slip in the nut, which is pushed in opposite the bolt hole and the bolt then pushed in, the screw end started in the nut and the bolt then screwed up by turning the head. This brings the two timbers tightly together and gives a perfectly dead weight on the hanger.

58 Stirrup Irons 20031

Fig. 45.

58 Stirrup Irons 20032

Fig. 46.

58 Stirrup Irons 20033

Fig. 47.

58 Stirrup Irons 20034

Fig. 48.

Fig. 49.

Fig. 50. -Von Dorn Hanger.

The following table shows the size of iron bar recommended for stirrups, and also the safe strength of the stirrup:

SIZE OF IRON

SIZE Of JOIST SUPPORTED.

SAFE STRENGTH OF

STIRRUP.

X 2

inches.

2 x 8 to 3x 10

10,000

pounds.

x 2

"

4 x10 to 4 x 12

18,000

"

x 3

"

6 x 12 to 3 x 14

22,000

"

x 3

"

8 x 12 to 4 x 14

30,000

"

1x 4

"

6 x 14

36,000

"

x 3

"

8x14

40,000

"

5/8 x 4

"

10x14

45,000

"

Fig. 50 shows a new style of hanger recently placed on the market It is forged from rolled steel and should make a very strong hanger, but would be improved by hooking the top plates over the back of the beam. The hanger is designed to be fastened to the trimmer by spikes.