Fig. 2717.
Fig. 2718.
When, however, the piece requires to be bent to more than one sweep or bend, the process requires to be changed somewhat. Thus, suppose the middle is to be bent circular and the two ends left straight, and the strap on the piece to be bent is provided with a piece, such as in [Fig. 2716], the ends b engaging in eyes in the strap, and the screw a abutting against the end of the piece to bind the strap firmly upon the ends, as in [Fig. 2717], in which the piece is shown within the strap. After it has been bent to the former it is held there by straps and wedges, as shown in [Fig. 2718].
Fig. 2719.
The next operation is to lock the curve, as shown in [Fig. 2719], between an inside and outside former by means of straps a a and wedges c, when the ends d of the piece may be bent up to the dotted lines and locked to the ends of the top former by straps and wedges.
The length of time a piece should be boiled or steamed for the bending process depends upon the size of the piece and the kind of wood, hard wood requiring longer boiling or steaming. A piece of ash, say 2 by 4 inches in cross section, would require about six hours’ steaming with a low pressure of moist or wet steam, but it would not suffer damage if it were steamed for a day. Pieces not over half an inch thick may be bent after steaming them about half an hour.