Plane-bit.
The cutter of a plane; generally termed the
plane-iron. The cutting-edges of planeirons are generally a right line, but, for some purposes, they are made with rectangular or curved grooves.
They are set in the stock at various angles with the sole, 45° being termed
common pitch: this is employed in bench-planes for soft wood; 50°,
York pitch, for mahogany and hard woods; 55°,
middle pitch, is used in molding-planes for soft woods, and smoothing-planes for mahogany and hard woods; 60°,
half pitch, in molding-planes for hard woods.
The iron rests on the
bed, and is held between this and the abutment by a wedge which adjusts its projection beyond the mouth.
In metalworkers' planes the iron is set at an angle of 70° or 80°; it is adjusted by a vertical screw, and an end screw and block is substituted for the wedge; its face is frequently grooved, giving a greater penetration, the smoothing being afterward effected by a plane with a narrow bit
Double irons are generally employed in the better class of planes; the upper, called the
break-iron, does not cut, but breaks the shaving, allowing the lower bit to effect a smooth-cutting action without splitting the wood.
The
scraping-plane, having its bit perpendicular or nearly so, is also employed on hard wood and ivory; with its edges serrated, such a plane is used by cabinet-makers for roughing veneers and the surfaces to which they are glued.
The width of plane-irons varies according to kind.
| Modeling-planes | 3/16-1 1/2 inches. |
| Smoothing-planes | 1 3/4-2 3/8 inches. |
| Rabbet-planes | 3/8-2 inches. |
| Jack-planes | 2-2 1/4 inches. |
| Panel-planes | 2 1/2 inches. |
| Trying-planes | 2 1/8-2 1/2 inches. |
| Long-planes | 2 5/8 inches. |
| Jointer-planes | 2 3/4 inches. |
| Cooper's jointer-planes | 3 1/2-3 3/4 inches. |
