Fig. 1645.
It is obvious that the chuck shown in [Fig. 1636] can be mounted on a supplemental and swiveling table as shown in [Fig. 1644], thus greatly facilitating the chucking of the work and facilitating the means of presenting different surfaces or parts of the work to the tool without requiring to unchuck it. The pawls, also, may in heavy work have two pins to enter the work-table holes and be connected by a strap as in [Fig. 1645].
Fig. 1646.
In the exigencies of the general machine shop it sometimes happens that it is required to plane a piece that is too wide to pass between the uprights of the planing machine, in which case one standard or upright may be taken down and the cross slide bolted to the other, as in [Fig. 1646], the blocks a, a, being necessary on account of the arched form of the back of the cross slide. In the example given the plates to be planed were nearly twice as wide as the planer table and were chucked as shown, the beam d resting on blocks e, f, and forming a pathway for the piece c, which was provided with rollers at each end so as to move easily upon d. The outer end of the plate was clamped between b and c, and the work was found to be easily and rapidly done. In this chucking, however, it is of importance that beam d be carefully levelled to stand parallel with the planer table face, while its height must be so adjusted that it does not act to cant or tilt the table sideways as that would cause one V of the planer ways to carry all or most of the weight, and be liable to cause it to cut and abrade the slide surfaces.
Cutting Tools for Shaping and Planing Machines.—All the cutting tools forged to finished shape from rectangular bar steel, and described in connection with lathe work, are used in the planer and in the shaper, and the principles governing the rake of the top face remain the same. But in the matter of the clearance there is the difference that in a planing tool it may be made constant, because the tool feeds to its cut after having left the work surface at the end of the back stroke, hence the clearance remains the same whatever the amount or rate of feed may be.
