Fig. 1611.
Mr. Thomas has also patented a system of forced oil circulation for large planers. In this system a pump p, [Fig. 1611], draws the oil from the cellars c (which are usually provided on the ends of planer beds) and delivers it through pipes passing up to the sides of the Vs, thus affording a constant flow of oil. A reservoir at the foot of the pump enables the dirt, &c., in the oil to settle before it enters the pump, which can be operated from any desirable part of the planer mechanism. The pendulums are also used in connection with the forced circulation.
As the work is fastened to the upper face of a planing machine table either directly or through the intervention of chucking devices, the table must be pierced with holes and grooves to receive bolts or other appliances by means of which the work or chuck, as the case may be, may be secured.
For receiving the heads of bolts, T-shaped grooves running the full length of the table are provided, and in addition there are sometimes provided short T-grooves, to be shown presently.
For receiving stops and other similar chucking devices, the tables are provided with either round or square holes.
Fig. 1612.
In [Fig. 1612] is shown a section of a table provided with T-grooves and rows of round holes, a, b, c, d, e, which pass entirely through the table, and hence must not be placed so that they will let dirt fall through to the V-guides or the rack. Tables with this arrangement of holes and grooves are usually used upon small planers in the United States, and sometimes to large ones also.
It is obvious that the dirt, fine cuttings, &c., will pass through the holes and may find its way to the V-guideways. Especially will this be the case when water is used upon the tool to take smooth cuts upon wrought iron and steel. To obviate this the construction shown in [Fig. 1613] is employed.