Part 46

If the reflective surfaces be coated with red, blue, or green aniline, various colored effects can be obtained. Instead of fragile glass the gems may be produced by means of well-polished pieces of steel or bronze.

«Other Tin-Lead Alloys.»—Percentage of lead and specific gravity.

P. C. S. G. 0 7.290 1 7.316 2 7.342 3 7.369 4 7.396 5 7.423 6 7.450 7 7.477 8 7.505 9 7.533 10 7.562 11 7.590 12 7.619 13 7.648 14 7.677 15 7.706 16 7.735 17 7.764 18 7.794 19 7.824 20 7.854 21 7.885 22 7.916 23 7.947 24 7.978 25 8.009 26 8.041 27 8.073 28 8.105 29 8.137 30 8.169 31 8.202 32 8.235 33 8.268 34 8.302 35 8.336 36 8.379 37 8.405 38 8.440 39 8.476 40 8.512 41 8.548 42 8.584 43 8.621 44 8.658 45 8.695 46 8.732 47 8.770 48 8.808 49 8.846 50 8.884 60 9.299 70 9.736 80 10.225 90 10.767 100 11.370

«Tin Statuettes, Buttons, etc.»—

I.—Tin 4 parts Lead 3 parts

This is a very soft solder which sharply reproduces all details.

Another easily fusible alloy but somewhat harder, is the following:

II.—Tin. 8 parts Lead 6 parts Antimony 0.5 part

«Miscellaneous Tin Alloys.»—I.—Alger Metal.—Tin, 90 parts; antimony, 10 parts. This alloy is suitable as a protector.

II. Argentine Metal.—Tin, 85.5 per cent; antimony, 14.5 per cent.

III.—Ashberry metal is composed of 78 to 82 parts of tin, 16 to 20 of antimony, 2 to 3 of copper.

IV. Quen’s Metal.—Tin, 9 parts; lead, 1 part; antimony, 1 part; bismuth, 1 part.

«Type Metal.»—An alloy which is to serve for type metal must be readily cast, fill out the molds sharply, and be as hard as possible. It is difficult to satisfy all these requirements, but an alloy of antimony and lead answers the purpose best. At the present day there are a great many formulas for type metal in which other metals besides lead and antimony are used, either to make the alloy more readily fusible, as in the case of additions of bismuth, or to give it greater power of resistance, the latter being of especial importance for types that are subjected to constant use. Copper and iron have been recommended for this purpose, but the fusibility of the alloys is greatly impaired by these, and the manufacture of the types is consequently more difficult than with an alloy of lead and antimony alone. In the following table some alloys suitable for casting type are given:

Lead Antimony Copper Bismuth Zinc Tin Nickel I 3 1 — — — — — II 5 1 — — — — — III 10 1 — — — — — IV 10 2 — 1 — — — V 70 18 2 — — 10 — VI 60 20 — — — 20 — VII 55 25 — — — 20 — VIII 55 30 — — — 15 — IX 100 30 8 2 — 20 8 X 6 — 4 — 90 — —

The French and English types contain a certain amount of tin, as shown by the following analyses:

English Types French Types I II III Lead 69.2 61.3 55.0 55 Antimony 19.5 18.8 22.7 30 Tin 9.1 20.2 22.1 15 Copper 1.7 — — —

Ledebur gives the composition of type metal as follows:

I II III IV Lead 75 60 80 82 Antimony 23 25 20 14.8 Tin 22 15 — 3.2

WATCHMAKERS’ ALLOYS: See Watchmakers’ Formulas.

«WHITE METALS.»

The so-called white metals are employed almost exclusively for bearings. (See Anti-friction Metals under Alloys.) In the technology of mechanics an accurate distinction is made between the different kinds of metals for bearings; and they may be classed in two groups, red brass and white metal. The {79} red-brass bearings are characterized by great hardness and power of resistance, and are principally used for bearings of heavily loaded and rapidly revolving axles. For the axles of large and heavy flywheels, revolving at great speed, bearings of red brass are preferable to white metal, though more expensive.

In recent years many machinists have found it advantageous to substitute for the soft alloys generally in use for bearings a metal almost as hard as the axle itself. Phosphor bronze (q. v.) is frequently employed for this purpose, as it can easily be made as hard as wrought or cast steel. In this case the metal is used in a thin layer, and serves only, as it were, to fill out the small interstices caused by wear on the axle and bearing, the latter being usually made of some rather easily fusible alloy of lead and tin. Such bearings are very durable, but expensive, and can only be used for large machines. For small machines, running gently and uniformly, white-metal bearings are preferred, and do excellent work, if the axle is not too heavily loaded. For axles which have a high rate of revolution, bearings made of quite hard metals are chosen, and with proper care—which, indeed, must be given to bearings of any material—they will last for a long time without needing repair.

WHITE METAL FOR BEARING. ──────+───────────────────────+──────+────────+──────+──────+──────+────── │ │ Tin │Antimony│ Zinc │ Iron │ Lead │Copper ──────+───────────────────────+──────+────────+──────+──────+──────+────── I │German, light loads │ 85.00│ 10.00 │ — — │ — — │ — — │ 5.00 II │German, light loads │ 82.00│ 11.00 │ — — │ — — │ — — │ 7.00 III │German, light loads │ 80.00│ 12.00 │ — — │ — — │ — — │ 8.00 IV │German, light loads │ 76.00│ 17.00 │ — — │ — — │ — — │ 7.00 V │German, light loads │ 3.00│ 1.00 │ 5.00│ — — │ 3.00│ 1.00 VI │German, heavy loads │ 90.00│ 8.00 │ — — │ — — │ — — │ 2.00 VII │German, heavy loads │ 86.81│ 7.62 │ — — │ — — │ — — │ 5.57 VIII │English, heavy loads │ 17.47│ — — │ 76.14│ — — │ — — │ 5.62 IX │English, medium loads │ 76.70│ 15.50 │ — — │ — — │ — — │ 7.80 X │English, medium loads │ 72.00│ 26.00 │ — — │ — — │ — — │ 2.00 XI │For mills │ 15.00│ — — │ 40.00│ — — │ 42.00│ 3.00 XII │For mills │ — — │ 1.00 │ 5.00│ — — │ 5.00│ — — XIII │For mills │ — — │ 1.00 │ 10.00│ — — │ 2.00│ — — XIV │Heavy axles │ 72.70│ 18.20 │ — — │ — — │ — — │ 9.10 XV │Heavy axles │ 38.00│ 6.00 │ 47.00│ — — │ 4.00│ 1.00 XVI │Rapidly revolving axles│ 17.00│ 77.00 │ — — │ — — │ — — │ 6.00 XVII │Very hard metal │ 55.00│ — — │ — — │ 70.00│ — — │ 2.50 XVIII │Very hard metal │ 12.00│ 82.00 │ 2.00│ — — │ — — │ 4.00 XIX │Cheap metal │ 2.00│ 2.00 │ 88.00│ — — │ — — │ 8.00 XX │Cheap metal │ 1.50│ 1.50 │ 90.00│ — — │ — — │ 7.00 ──────+───────────────────────+──────+────────+──────+──────+──────+──────

Other white bearing metals are:

XXI.—Tin, 8.5; antimony, 10; copper, 5 parts.

XXII.—Tin, 42; antimony, 16; lead, 42 parts.

XXIII.—Tin, 72; antimony, 26; copper, 2 parts.

XXIV.—Tin, 81; antimony, 12.5; copper, 6.5 parts.