Figure 87.—Hand rock drill nnd hammer.


83 49-50

inches In diameter and the other holes 10 inches in diameter. (See fig. 17.) These augers are useful in drilling holes to place charges for road craters.

■ 50. Primers.—A primer is a block or package of high explosive with a cap placed in it, or detonating cord tied through or around it. A charge is primed by placing in it a primer prepared as above. The purpose of the primer is to insure detonation of charge. The cap or detonating cord sets off the block or sflck of explosive in which It is placed, which in turn sets off the remainder of the charge.

a. Primer of TNT or dynamite, with nonelectric cap and fuze.—Cut fuze off square with fuze cutter. See that no dirt is in the open end of the cap, then slip it over the fuze as far down as it will go. Hold the fuze in one hand and crimp cap to fuze with cap crimper, making crimp near open end of cap. Next, put cap with fuze attached into the hole in TNT block or dynamite stick (figs. 89, BO. and 91). The twine holding the cap in place must be tied so that when the fuze is pulled, the twine takes the pull and the cap is not moved In the hole.

b. Primer of TNT block or dynamite, with electric cap.— Place cap in hole in TNT block, making a clove hitch in the cap end of the lead wires. Pass this loop around TNT block and pull tight, leaving the wire slack from the loop to the cap. The same procedure Is used with a dynamite stick (see flg. 92); another method is to tie a preliminary half hitch near the bottom of the stick before tying the clove hitch near the top.

c. Primer with detonating cord and TNT block.—He cord directly to the TNT block as shown in figure 93. To do this, tie one-half of a clove hitch, take one full turn around the block, then tie the second half of the clove hitch. Pull all Ihree turns tight so they will fit snugly against each other end against the block.

d. Primer with ammonium nitrate cratering charge.—For electrical firing place an electric cap in the cap well pro-Tided on the side of the container. Make several turns with the lead wires around the knob above the cap well and pull tight, so that a pull on the lead wires will not dislodge the

B4 50-51

Expedient Guns

FiocriUE 89.—Primer made at TNT block and nonelectric cap.

cap <flg. 94). To make a primer using detonating cord, pass the detonating cord all the way through the tunnel itrom top to bottom) on the side of the container and tie an overhand knot in the lower end to prevent the cord from pulling out of the tunnel. Both means of detonating should be used simultaneously. Do not use detonating cord or electric-cap leads to lower the ammonium nitrate cratering charges into holes; use a cord attached to the ring in the top of the charge.

■ 51. Detonating AssEMBLY^-Detonating assemblies may be prepared prior to an operation so that the detonating device may be quickly attached to an emplaced charge such as a

B5 51-52



Fjguke 90.—Prlm«?r madf with nonelectric stick.

-D T (C)TIE OTHER * END OF CORO TO FUZE cap Ln end al dynamite crater explosive or a bangalore torpedo. The assembly is made by binding a nonelectric cap to a piece of detonating cord (as shown in fig. 96), allowing sufficient length or detonating cord to tie a square-knot splice to the charge. Time fuze is crimped to the cap, and a fuze lighter is crimped to the other end of the fuze. (See fig. 95.)

■ 52. Nonelectric Connections.—a. To attach cap (electric or nonelectric) to detonating cord.—Lay the cap and time fuze alongside the detonating cord, with the cap pointing in the direction of the charge. Bind the cap and detonating cord securely together, using either friction tape or twine, as shown in figure 96.

b. To splicc detonating cord.—Use a square knot to tie two ends of detonating cord together. The loop in the end of each pieoe of detonating cord must be at least 6 Inches long (fig. 97).

c. To connect a branch line o/ detonating cord to a main line.—Use two half hitches to tie a branch line to a detonat-

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