The advantages of shoes provided with good screw heel-calks are so manifold that they deserve marked preference over shoes sharpened by the ordinary methods. The common objections urged against screw-calks,—namely, that they loosen and are lost, or break off, are not worthy of serious consideration, since these evils are merely the result of unskilful workmanship and poor material. Shoes with screw heel-calks are the best shoes for winter, especially for horses that have to work hard and continuously.
Fig. 163.
Sharp screw-calks with Whitworth
thread (half-inch, natural size).
Fig. 164.
Whitworth tap (half-inch,
half natural size).
Balling with snow is prevented by using shoes narrow in the web and concave upon the ground-surface (convex iron), and thoroughly oiling the sole and frog. Sole-pads of felt, leather, or straw serve the same purpose. Balling with snow is best prevented by a rubber sole-and-frog pad, or by a “stopping” of a patent hoof cement known in Germany as “huflederkitt.”
4. Shoeing with Peg-Calks.—The calks are merely stuck into the calk-holes, hence their name. Round and square peg-calks are used, but the former are better than the latter.
The inventor of round peg-calks is Judson, an American. The shoes differ in no respect from the ordinary flat shoes. It is necessary that the tap of the calk have a moderately conical form, and exactly fit into the calk-hole of the shoe. The taper of the calk-tap is correct if for every ten thirty-seconds of an inch in length it increases or diminishes one-thirty-second of an inch in diameter (equal to one inch in every ten inches of length).