To temper the hammer: Place the whole hammer in the fire and heat it red hot. Grasp it with a pair of pick-up tongs through the eye. Dip the face in water half way up to the eye, and hold it there until the face is chilled off. Reverse by placing the peen end into the water. While this is cooling dip up enough water with the hand to keep the face of the hammer cold. Take it out and polish both ends with a piece of emery cloth wrapped around a piece of wood. The colours now are beginning to run from the middle toward the ends. When the purple colour reaches either end plunge that end into water, holding it in the water until the purple colour reaches the other end. Then plunge the whole hammer in water. This tempering darkens the hammer if it has been previously polished. Rubbing well with emery cloth again will restore the brightness. The hammer is ready for the handle. A hammer of this kind can be made without the help of a second person.
Processes in making peen hammer
Round peen hammer: The form and dimensions for this hammer are given here.
Step in making hammer
Stock: A piece of 11⁄2-in. square tool steel. This hammer, too, is best made on the end of a bar about 20 ins. in length. With a centre-punch mark off 2 ins. from the end. This spot marks the centre of the eye. Place this end in the fire. One inch from the end fuller down on the four sides of the bar (1). This makes a neck one inch in diameter and having eight sides. Place it back in the fire and heat again. Now put the bar again on the fuller 2 ins. from the first fuller (1). This time fuller only two sides, the two sides opposite the centre-punch mark. Fuller so that the thickness measures 11⁄4 ins. This means only 1⁄8 in. depression on the two sides. Put again into the fire and draw the first end out so that it measures 1 in. octagonal, any length. (See [sketch 2].) Heat again, this time the whole body of the piece. Punch a hole with the eye-punch where the centre-punch was made. The hole will be a little less in size than the finished hole will be (see [sketch]) to allow for the increase in size while working the metal into shape. Put the drift pin into the hole. Drive it through until the small end just shows through on the other side. Place a fuller over the hole and work the metal out sidewise by striking on the top of the fuller with a sledge hammer. This requires a helper to do the heavy work. While the heavy work is being done the steel must be heated many times, but always without the drift pin. Keep the drift pin in water while the hammer is being heated, as the pin must always be cold when driven into the eye. Drive it in a little farther each time, so that by the time the centre is finished the hole will be the proper size (3). The thickness of the metal around the eye should be about 1⁄8 in. on the outer edges and 3⁄16 in. in the centre. This tapers a little from the centre outward, as is shown in the drawings. Put the 3⁄4-in. bottom fuller on the anvil and place the neck of the hammer on this and a top fuller above that. Strike on the fuller and reduce the neck until it measures about 3⁄4 in. in diameter, keeping the octagonal shape all the while.
Heat the hammer again where the face should be, and fuller down between the body and the face so that this will measure about 11⁄8 in. square, using the same large fullers as before and making it octagonal. This finishes up completely the body of the hammer between the face and the peen.