Fig. 1580.
[Fig. 1579] is a front view, and [Fig. 1580] a sectional top view, of a sunk vertical slide, corresponding to that shown in [Figs. 1573] and [1578], but in this case the gib has a tongue t, closely fitted into a recess or channel in the vertical slider s, and to allow room for adjustment, the channel is made somewhat deeper than the tongue requires when newly fitted. The adjustment is effected by means of two sets of screws, a and b, of which the former, being tapped into the gib, serve to tighten, and the latter, being tapped into the slide, serve to loosen the gib. By thus acting in opposite directions the screws serve to check each other, holding the gib rigidly in place. To insure a close contact of the gib against the vertical surface of the slide, the screws b are placed in a line slightly outside of the line of the screws a.
Fig. 1581.
[Fig. 1581] represents a similar construction when the slideways on the swing frame project outwards, instead of being sunk within that frame.
Fig. 1582.
[Fig. 1582] represents the construction of the Pratt & Whitney Company’s planer head, in which the swivel head instead of pivoting upon a central pin and being locked in position by bolts, whose nuts project outside and on the front face of the swing frame, is constructed as follows:—