US2356966A - Method of making shot - Google Patents

Description

9 N. J. BARDELL METHOD OF MAKING SHOT Filed Aug. 50, 1943 //////7 w M g i v i j ods.

Patented Aug. 29, 1944 UNITED. STATES PATENT OFFICE METHOD OF MAKING SHOT Nicholas J. Bardell, Chicago HeightsgIlL, assignor to Mid-West Forging & Mfg. Co., Chicago,

Ill., a corporation of Illinois I a Application August 30, 1943, Serial N0.-500,589

1 Claim.

This invention relates to improvements in themethod of making shot, and more especially to forged projectiles with ogive heads or points such as are commonly used in cannons ranging from 20 to 60 millimeters; although it is to be understood that these sizes are not intended to limit the scope of my invention, as the improved method may be employed in making shot of any size.

Such shot are commonly made from round bars and heretofore it has been customary to first take a bar substantially the same length as the completed shot to be made and then point one end by hammering or swaging. In this operation considerable excess metal had to be hammered forwardly of the point in the form of a tube (to give a closed point to the completed pro-' pectile); and this metal was then cut off and wasted.

Such shot have also heretofore been made by turning down the end of the bar on a lathe to give the desired pointed head or end; and it is obvious that by such a method there is also waste of considerable material. In the practice of my new method this waste is eliminated. As will be described more in detail hereinafter, I first take a bar substantially shorter than the combined length of two shot and then make two shot from this bar with practically no waste of material. For example, in the making of 37 millimeter shot, 5-inches long, I may employ a bar about 8 -inches long from which I make two such shot.

In the practice of my invention it is also possible to employ bars having a smaller diameter than those used by the older process for the making of shot of the same size. This results in a saving of time and labor in the final machining of the shot to exact size.

My new method also produces a shot with a harder point than is produced by the older meth- In fact I have found that I can produce armor piercing shot. For example, a, 3'7 millimeter shot produced by my method is capable of piercing armor plate from one to one and onehalf inches thick without substantial mushrooming or flattening of the point.

In the practice of my invention the shot is rotated in a swaging machine in the direction in which it is rotated by the rifling in the barrel of the cannon when discharged; and I have found that this rotation of the shot in the swaging machine affects the structure of the shot so that its use in the cannon and its armor piercing properties are improved.

I have also found that the practice of my new invention effects a saving in the dies, over the older methods heretofore used.

In the accompanying drawing Fig. 1 is a view of the hammer used for cutting a bar in two and pointing the adjacent ends, Fig. 2 is a similar view showing the bar substantially cut, Fig. 3 is a view of one of the shot out from the bar with the point as formed by the hammer, Fig. 4 is a view of the shot in the swaging machine, Fig. 5 is a view of the shot after it comes from the swaging machine, Fig. 6 is a similar view showing the shot ready for the final machining operation, Fig. '7 is a plan view of one of the dies of the hammer and Fig. 8 is a similar view of one of the dies of the swaging machine.

As shown in the drawing, [0 indicates a round bar for forming two shot. For example, this bar may be about 38 millimeters in diameter and about 8 /2-inches long for forming two 37 millimeter shot each 5-inches long.

H, II indicate the upper and lower dies of the hammer, one of these dies being shown in plan view in Fig. '7.

[2 indicates a stop against which the bar Ill is placed when being operated upon by the hammer in order to center the same. The upper die II is pounded downwardly against the bar which rests on the lower die as the bar which has previously been been heated to red heat is rotated. The hammering operation is continued until the bar is cut in two as shown in Fig. 2, and each of the halves is then in the shape of a partially formed shot as shown in Fig. 3. The head or point, however, is still rather roughly shaped. With the shot still red hot it is placed in a swaging machine of well known construction as indicated in Fig. 4. This machine is provided with two dies l3, I3, one of which is shown in plan view in Fig. 8. These dies are hammered together by contact of the rollers l4 and [5 in a manner well known in connection with conventional swaging machines.

During the hammering operations the shot I0 is rotated in the direction indicated by the arrow, that is, in the same direction that the shot will be rotated by the rifling when fired from the cannon.

The dies [3, 13 are provided with cavities l3a which shape the head of the shot to give it the ogive point preparatory to the machining or final finishing. Upon leaving the swaging machine the shot Will ordinarily have at the point a small projecting stem I6 as shown in Fig. 5 and this stem is ordinarily cut off as shown in Fig. 6 before the shot is put in the lathe or automatic screw machine for the final finishing. The machine for this final finishing is not shown herein as the final machining is a process well known in the art and need not be described in particular here.

In making shot as described herein, the steel is modified so that its structural lines for some distance inside the ogival point run generally parallel to the outer surface or are at least inwardly defiected or concentrated, and it is believed that this is, in part at least, the cause of the superior penetrating properties of the shot.

While I have shown and described certain improvements of my invention, it is to be understood that it is capable of many modifications. Changes, therefore, in the method and process may be made without departing from the spirit and scope of the invention as is disclosed in the appended claim, in which it is my intention to I claim all novelty inherent in my invention as broadly as permissible, in view of the prior art.

What I claim as new, and desire to secure by Letters Patent, is:

The method of making shot, comprising: producing a round bar slightly larger in diameter than the completed shot and substantially shorter than twice the length of the completed shot; softening said bar by heat; cutting said bar in the center and pointing the adjacent ends of the cut pieces by hammering while the shot is rotated whereby two pointed shot are formed, each point consisting of flattened segmental areas radiating from the point; swaging the pointed ends substantially to the desired pointed shape while rotating the shot in the direction in which it will be rotated when fired; and completing the shot by machining.

NICHOLAS J. BARDELL.

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