Toe-crack immobilized by lateral toe-clips: a, bearing-surface left free from pressure; b, heads of the rivets (nails) driven through holes previously drilled.
The shoe may be open, or a bar-shoe, or a short shoe with a rubber frog- and buttress-pad. Whatever expands the quarters closes a toe-crack. The Defay’s shoe ([Fig. 206]), or the Chadwick spring beneath a rubber pad, or beneath a bar-shoe with leather sole, if the frog be much shrunken, will be of service. The shoe should fit air-tight, except for an inch or so on both sides of the crack. Two lateral toe-clips ([Fig. 217]) are drawn up, and the wall between these clips is cut down from a twelfth to an eighth of an inch.
Fig. 218.
Spiral drill for boring the hole into which a round wire nail is driven to fasten a toe-crack: (a) three sided point of drill (similar to the point of a stilet of a cæcal trocar).
After the shoe has been nailed on tight the toe-crack should be immobilized. The best method is by buried nails. Slots are burned or cut on opposite sides at a distance of an inch from the crack. With a spiral drill ([see Fig. 218]) bore a hole from a slot at right angles tothe crack. Make a similar hole on the opposite side. Make the holes continuous by introducing a straight hot wire. The rivet may be an ordinary round wire nail which has been softened by bringing it to a yellow heat and allowing it to cool slowly. It is driven through and the ends firmly clinched. Such a nail is easily placed, need not press upon fleshy leaves, can not be stripped off or lost, and holds fast. The horse should stand on the foot while the rivet is being clinched. Two are sufficient for a complete crack ([Fig. 217]).
Fig. 219.
A, Vachette burning iron for making the two slots to receive the ends of the hook; b, shoulder; B, Vachette hook; C, pincers for forcing the hook into the wall.