Plate Xiii

Commercial Metals and Alloys. Many handtoadcrs are situated in localities where they cannot buy tin or antimony easily, and they may wish to use scrap lead or commercial alloys of lead. When one reads of bullet alloys made of definite proportions of metals, the idea is sometimes created that it is necessary to be very precise about one's alloys. This is true in the case of an occasional rifle that may happen to be cantankerous. In general, any alloy that can be cast into

181 bullets which shoot accurately is a good bullet alloy, even if it has cheese in it. But, in order that one may have some idea of what he is using, the following composition of common commcrcial alloys are given. These alloys are apt to vary, but the data given is a good average.

Pig Lead. Name given to commercially pure lead. About 99.6% lead. Melting point, 3274° C. (621° F.)

Block Tin. Practically pure tin. The impurities are negligible from a bullet casting standpoint. Melting point, 231.9" C. (447.8° F.)

Antimony. Contains traces of other metals, but is essentially pure antimony. Melting point, 630.5° C. (1167° F.). Compare the melting point of antimony with those of lead and tin and you will see why this is a difficult metal to work with over the kitchen stove.

Block Lead. As sold by plumbing shops, this may contain anything. It is scrap, melted up. Try indenting it with the thumb nail; if soft, harden as desired. If it is fairly hard, try it as it is. It is better to get pig or pure commcrcial lead, if available.

Lead Pipe. This is made of commercially pure lead.

Cable Sheathing. Practically the same as lead pipe. Storage Battery Plates and Grids. 9% to 11%

antimony, balance lead.

Storage Battery Connectors. These are softer than the plates and grids. About 3% antimony and die balance lead. Make a very good alloy for all-around use.

Type Metal. About 82% lead, 3% tin and 15% antimony.

Linotype Metal. Composed of 4% Tin, 11 to ii/4% antimony and the balance lead. Melts at approximately 450° F. Brinell hardness 19.0 at 20° C. This alloy is all right just as it is for very hard bullets. As it is used extensively by newspapers, it can be obtained almost anywhere newspapers are printed.

Monotype Metal. 8 to 9% tin, 17% to igl/i% antimony, balance lead. Brinell hardness 22.5 to 23.0 at

182 20° C. Melting point about 460° F. While this alloy is unnecessarily hard for bullets, it can be used just as it is. It is not used as commonly as linotype metal.

Wiped Joints. When sawed from the pipe and melted, will be from io^o to 15% tin and the balance lead.

Babbit Metal. Varies a great deal. That for heavy duty bearings runs around 83 % tin, 11% antimony, and 6% coppcr. For low speed bearings, lead is substituted for the tin. The copper will never melt, but will be suspended irregularly through the mass as minute particles.

Plumbers' Solder. Used for wiped joints. 67^? lead and 33 % tin.

Cal. .22 Bullets. Mosdy of lead, but recendy a lot of hard bullets have been put on the market. Antimony is used mosdy for hardening them. Treat in the same way as block lead.

The reader ihotild bear in mind that practically all of the commercial alloys in common use vary considerably in their composition and the best that can be done in such a brief ¿pace is to give a composite of information obtained from reliable source. While these miscellaneous alloys can be Bsed and doctored up for making ballets, it is far better to use alloys of known ingredients so that they can be duplicated at any time.

Modern Bullet Mould.

A—Hinge. B—Block half. C—Alignment dowel pin. D—Cavity.

E—Top surfacc o! mould blocks. F—Swinging gate, with sprue cutter.

Illustrating mould which cast imperfect bullets and which has hww "vftntPrl" to rftnoHy the difect.

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  • erna
    Can linotype metal be substituded for babbitt?
    8 years ago

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