5. Surfaces.—That part of the hoof-surface of the shoe which is in contact with the hoof (bearing-surface of the shoe, [Fig. 109, a]) should be horizontal and wide enough to cover the wall, the white line, and from a twelfth to an eighth of an inch of the outer edge of the sole. Shoes for large hoofs require a broader bearing-surface than those for small hoofs. The concaving, or “seating” ([Fig. 109, b]), should be made deeper or shallower, according to the nature of the sole. Shoes for hoofs with strongly arched (very concave) soles, do not require any concaving (hind hoofs, narrow fore-hoofs). The object of concaving is to prevent pressure of the shoe upon the horny sole except at its margin.
Fig. 109.
Transverse section of a branch of a
front shoe: a, bearing-surface;
b, concaving; c, fullering,
or “crease”; d, nail-hole.
The ground-surface of the shoe should be flat and perfectly horizontal, except at the toe, which may be turned upward (rolled toe, “rolling motion”).
6. Borders.—The outer border should usually be moderately base-narrow,—that is, the circumference of the ground-surface of the shoe should be less than the circumference of its hoof-surface; in other words, the entire outer border of the shoe should be bevelled under the foot. Shoes made base-narrow are not so easily loosened, and materially assist in preventing interfering. The inner border should be moderately rounded.
Fig. 110.
(a) correct and (b) incorrect fullering.
7. The “Fullering” ([Fig. 109, c]).—In depth it should be about two-thirds the thickness of the shoe, of uniform width, and “clean.” A fullering is not absolutely necessary, but it makes the shoe lighter in proportion to its size, facilitates a uniform placing of the nail-holes, renders the ground-surface somewhat rough, and, because it is rather difficult to make, increases the workman’s skill.