Beside all this you need a good man. It does not make much difference how completely the hardening department is fitted up, if you expect good work, a small percentage of loss and to be able to tackle anything that comes along, you must have a good man, one who understands the difference between low- and high-carbon steel, who knows when particular care must be exercised on particular work. In other words, a man who knows how his work should be done, and has the intelligence to follow directions on treatments of steel on which he has had no experience. Jewelers' tools, especially for silversmith's work, probably have to stand the greatest punishment of any all-steel tools and to make a spoon die so hard that it will not sink under a blow from an 1,800-lb. hammer with a 4-ft. drop, and still not crack, demands careful treatment. To harden such dies, first cover the impression on the die with paste made from bone dust or lampblack and oil. Place face down in an iron box partly filled with crushed charcoal, leaving back of die uncovered so that the heat can be seen at all times. Heat slowly in furnace to a good cherry red. The heat depends on the quality and the analysis of steel and the recommended actions of the steel maker should be carefully followed. When withdrawn from the fire the die should be quenched as shown in Fig. 80 with the face of die down and the back a short distance out of the water. When the back is black, immerse all over. [Illustration: FIG. 80.--Quenching a die, face down.] If such a tank is not at hand, it would pay to rig one up at once, although a barrel of brine may be used, or the back of the die may be first immersed to a depth of about 1/2 in. When the piece is immersed, hold die on an angle as in Fig. 81. [Illustration: FIG. 81.--Hold die at angle to quench.] This is for the purpose of expelling all steam bubbles as they form in contact with hot steel. We are aware of the fact that a great many toolmakers in jewelry shops still cling to the overhead bath, as in Fig. 82, but more broken pieces and more dies with soft spots are due to this method than to all the others combined, as the water strikes one spot in force, contracting the surface so much faster than the rest of the die that the results are the same as if an uneven heating had been given the steel. TAKE TIME FOR HARDENING.--Uneven heating and poor quenching has caused loss of many very valuable dies, and it certainly seems that when a firm spends from $75 to $450 in cutting a die that a few hours could be spared for proper hardening. But the usual feeling is that a tool must be hurried as soon as the hardener gets it, and if a burst die is the result from either uneven or overheated steel and quenching same without judgment, the steel gets the blame. [Illustration: FIG. 82.--An obsolete method.]