In whetting the cutter, the screw of the cap iron should be loosened and the cap iron carried back until the screw stops at the top of the slot of the bit, as at C, Fig. 50. The screw is then tightened with the fingers to hold the cap in place; this gives a better grasp of the iron, though some workmen prefer to take the cap off entirely while whetting.
Fig. 51.—Whetting or Oilstoning the Beveled Side of a Cutter.
The bevel of the iron should be held exactly upon the surface of the oilstone, as shown at C, Fig. 50, the iron being grasped as in Fig. 51. Keep the right wrist rigid and allow the arm to swing from the shoulder, bending only at the elbow. In this way the rocking motion may be reduced to a minimum; this is necessary to preserve the bevel. Though the bevel may be maintained better by imparting a short circular motion to the plane iron, or to any edge tool which is being sharpened, it seems an awkward and fussy method of work, and rarely is used by an expert workman. By long practice the mechanic finds that a stroke made nearly the entire length of the stone will impart an edge quicker, and after the knack has been acquired, the bevel will be preserved just as well.
Turn the whetstone end for end frequently, and work upon the farther end, as in this way the stone may be kept true much longer than if one place upon it is used all the time. This will also minimize the danger of pulling the tool off from the nearer end of the stone, which will generally make regrinding necessary.
Fig. 52.—Whetting or Oilstoning the Plain Side of the Plane Iron.
When the beveled side has been whetted, lay the face, or the top of the iron, perfectly flat upon the stone, as in Fig. 52, holding it down with the fingers of the left hand, using the right hand only to move the iron back and forth. Care should be used that under no circumstances is the face of the iron lifted the slightest degree from the stone. At this stage of sharpening a plane iron, the utmost care is necessary that the face of the cutter does not lose its perfectly straight surface at the edge, as the slightest deviation from absolute accuracy at this place will prevent the cap iron from fitting properly, which will cause endless trouble, as the shavings will be forced between the cap and the face of the iron (see C. of this topic).
Fig. 53.—Shape
of Edge of
Plane Iron.