Fig. 1601.
Suppose, for example, that in [Fig. 1600] all the sides are at an equal angle, but that side e was planed down to the dotted line e, then all the weight of the table would fall on side a, and, moreover, the table would be liable to rock in the guideways, for whenever the combined weight of the table and the pressure of the cut was greatest on the right-hand of the middle x of the table width and the feed was carried from right to left, then the table would move over, as shown exaggerated in [Fig. 1601], because the weight would press guide g down into its guideways, and guide h would then rise up slightly and not fit on one side at all, while on the other side it would bear heaviest at point p. Great care is therefore necessary in planing and fitting these guides and ways, the processes for which are explained under the respective headings of “[Examples in Planer Work],” and “[Erecting Planers].”
In some designs the bed and table are provided with but one V-guideway, the other side of the table being supported on a flat side, and in yet another form the table is supported on two flat guideways.
Referring to the former the bearing surface of the V and of the flat guide must be so proportioned to that of the V that the wear will let the table down equally, or otherwise it would become out of parallel with the cross slide, and would plane the work of unequal thickness across its width.
Fig. 1602.
Referring to the second, which is illustrated in [Fig. 1602], it possesses several disadvantages.