Fig. 2283.
The first thing to do is to mark off the keyway by scribing lines on the surface of the shaft, indicating the location for the feather seat; and for this purpose nothing is better than the key seat rule shown in [Fig. 2279], in which w is the key seat rule, and s the shaft. After the lines are drawn they should be defined by centre-punch dots, as in [Fig. 2280], and then the metal should be cut out on the sides first, using a cape chisel, and cutting close to the side lines, as in [Fig. 2281], in which a is a cape chisel cut taken along one side, d a second cape chisel cut, being carried along the other side, c the cape chisel, c′ the cut taken by the chisel, and b a piece of metal to be cut out after the cape chisel has done its work. Suppose, now, the mass of the metal is removed, then the dovetailing is performed as follows: Next the setting or upsetting is proceeded with as shown in [Fig. 2282], which is a side sectional view. s is a set chisel driven by hammer blows against the walls of the feather seat (as against the end e), causing it to bulge up, as shown at f. This setting will enlarge the feather seat or recess, so that the wide part of the dovetail on the feather will just pass in (the dotted lines shown in [Fig. 2281] having, of course, been marked to the size of the feather, where it will, when fixed, meet the surface of the shaft). The feather is then placed in its seat and bedded properly by red marking applied to its bottom surface to show the high spots on the seat of the recess, and when properly bedded it is fastened, as in [Fig. 2283], in which s is a set chisel, which, by being struck with hammer blows, closes the bulged metal back again on the dovetail of the feather, and firmly locks it in the shaft. And all that remains is to file the shaft surface around the feather level with the surrounding surface, there being usually a little surplus metal from the upsetting.
Fig. 2284.
Fig. 2285.