Charts & Conversions
Weights
Relative Weights
Formula to calculate metal weight and cost from wax models:
- Wax weight (dwt.*) x specific gravity of desired metal** = weight of casting in dwt. x Cost/dwt. + Labor Charges = Cost of Casting.
- Allow some additional weight for the remaining gate.
The top line is the known material (in pennyweights). The first column is the desired material. For example, if you have a wax that weighs .7 dwt, and you want to know its corresponding weight in platinum, go down the wax column to platinum and multiply .7 dwt. (wax weight) by 21.45. 15.02 dwt’s is the corresponding weight in platinum.
Wax | Sterling | 10Y | 14Y | 18Y | 14W | 18W | Platinum | |
Sterling | 10.36 | 1.00 | 0.90 | 0.79 | 0.67 | 0.82 | 0.71 | 0.49 |
10Y | 11.60 | 1.11 | 1.00 | 0.89 | 0.74 | 0.92 | 0.79 | 0.54 |
14Y | 13.08 | 1.27 | 1.13 | 1.00 | 0.84 | 1.03 | 0.89 | 0.61 |
18Y | 15.60 | 1.49 | 1.34 | 1.19 | 1.00 | 1.23 | 1.06 | 0.73 |
14W | 12.65 | 1.22 | 1.09 | 0.97 | 0.81 | 1.00 | 0.86 | 0.59 |
18W | 14.65 | 1.41 | 1.26 | 1.12 | 0.94 | 1.16 | 1.00 | 0.68 |
PT | 21.45 | 2.04 | 1.85 | 1.64 | 1.38 | 1.70 | 1.46 | 1.00 |
*The specific gravity of wax is 1. **See Specific Gravity Chart or Relative Weights.
Weight Conversion |
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To convert: | ||
Pennyweights to grams | Multiply by | 1.55518 |
Grams to pennyweights | Multiply by | 0.64301 |
Ounces troy to grams | Multiply by | 31.1035 |
Grams to ounces troy | Multiply by | 0.0321507 |
Ounces avoirdupois to grams | Multiply by | 28.3495 |
Grams to ounces avoirdupois | Multiply by | 0.0352740 |
Ounces troy to ounces avoirdupois | Multiply by | 1.09714 |
Ounces avoirdupois to ounces troy | Multiply by | 0.911458 |
Pounds avoirdupois to kilograms | Multiply by | 0.4535924 |
Kilograms to pounds avoirdupois | Multiply by | 2.20462 |
Kilograms to ounces avoirdupois | Multiply by | 35.2740 |
Kilograms to ounces troy | Multiply by | 32.1507 |
Carat Weight |
|
Used in Weighing Precious and Semi-Precious Stones | |
1 carat | = 0.20 grams |
1 gram | = 5 carats |
1 carat | = 3.086 grains troy |
1 carat | = 0.007 ounce avoirdupois |
1 carat | = 100 points |
Troy Weight |
|
Used in Weighing the Precious Metals | |
24 grains | 1 pennyweight |
20 pennyweights (dwt.) | 1 ounce troy |
12 ounces | 1 pound troy |
5760 grains | 1 pound troy |
The troy ounce is about 10% heavier than the avoirdupois ounce. | |
31.1035 grams | 1 ounce troy |
1 gram | 15.432 grains troy |
1.555 grams | 1 pennyweight (dwt.) |
Temperatures
Torch Fuel Characteristics and Temperatures |
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Chemical Fuel | Formula | Special Characteristics | Flame Temp. w/Oxygen | Flame Temp. w/Air | BTU per lb. |
Acetylene | C2H2 | Burns hottest; popular fuel gas; not recommended for use with platinum | 6300°F | 4217°F | 21,499 |
Natural Gas | ** | Burns clean; economical to use | 4600°F | 3420°F | — |
Propane | C3H8 | Burns clean; economical to use | 4780°F | 3497°F | 21,260 |
Butane | C4H10 | Low heat; available in portable containers | 4995°F | 3443°F | 21,298 |
Hydrogen | H2 | High heat; cleaner than acetylene | 4850°F | 3713°F | 61,085 |
MAPP® | C3H4 | Somewhat concentrated high-temperature flame | 5300°F | 3600°F | 2300 |
** Typical analysis: methane 83.4%, ethane 15.8%, nitrogen 0.8%.
High Temperature Judged By Color |
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°F | °C | Color |
752 | 400 | Red heat, visible in dark |
885 | 474 | Red heat, visible in twilight |
975 | 525 | Red heat, visible in daylight |
1077 | 581 | Red heat, visible in sunlight |
1292 | 700 | Dark red |
1472 | 800 | Dull cherry red |
1652 | 900 | Cherry red |
1832 | 1000 | Bright cherry red |
2012 | 1100 | Orange-red |
2192 | 1200 | Orange-yellow |
2372 | 1300 | Yellow-white |
2552 | 1400 | White welding heat |
2732 | 1500 | Brilliant white |
2912 | 1600 | Dazzling white, blue-white |
Annealing Temperature Guide
Time at the full annealing temperature will depend on the thickness of the section, but 1 minute per mm of section should be sufficient for thickness up to about 5 mm. Too frequent annealing or annealing for too long can cause grain growth which may make subsequent working or polishing to a smooth surface more difficult.
Specific Gravity and Metal Melting Points |
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Metal | Melting Point °C | Melting Point °F | Specific | Metal | Melting Point °C | Melting Point °F | Specific | |
Aluminum | 660 | 1220 | 2.7 | Iridium | 2454 | 4450 | 22.5 | |
Bronze | 1060 | 1945 | 8.8 | Iron | 1535 | 2793 | 7.9 | |
Copper | 1083 | 1981 | 8.9 | Lead | 327 | 621 | 11.3 | |
Gold (fine) | 1063 | 1945 | 19.3 | Nickel | 1455 | 2651 | 8.8 | |
22K Yellow | 977 | 1790 | 17.3 | Nickel Silver | 1110 | 2030 | 8.8 | |
22K Coin | 940 | 1724 | 17.2 | Palladium | 1549 | 2820 | 12.2 | |
18K Yellow | 1030 | 1885 | 15.5 | Platinum (Pure) | 1774 | 3225 | 21.4 | |
18K Green | 966 | 1770 | 15.6 | 5% Cobalt | 1765 | 3209 | 20.8 | |
18K Rose | 932 | 1710 | 15.5 | 5% Iridium | 1790 | 3254 | 21.4 | |
18K White | 940 | 1725 | 15.7 | 10% Iridium | 1800 | 3272 | 21.5 | |
14K Yellow | 960 | 1760 | 13.4 | 5% Ruthenium | 1795 | 3263 | 20.7 | |
14K Green | 835 | 1535 | 13.6 | Silver (Fine) | 961 | 1762 | 10.6 | |
14K Rose | 827 | 1520 | 13.4 | Sterling | 920 | 1640 | 10.4 | |
14K White | 975 | 1785 | 13.7 | Stainless Steel | 1371 | 2500 | 7.8 | |
10K Yellow | 980 | 1796 | 11.6 | Titanium | 1800 | 3272 | 4.5 |
Measurements
Fluid Measurement
- 1 quart = 32 ounces (fluid) = 2 pints = 1/4 gallon = 57 cubic inches
- 1 gallon = 4 quarts = 128 ounces (fluid) = 3.78 litre and 231 cubic inches = 0.134 cubic feet
- 1 litre = 1,000 cc (slightly more than 1 quart U.S.) = 0.264 U.S. gallons
- 1 cubic foot = 7.481 U.S. gallons = 1,728 cubic inches
- 1 imperial gallon = 1.2 U.S. gallons = 4.59 litre = 277.27 cubic inches
Length Conversion
To convert: | ||
Millimetres to inches | Multiply by | 0.0393701 |
Inches to millimetres | Multiply by | 25.4 |
Metres to inches | Multiply by | 39.3701 |
Inches to metres | Multiply by | 0.0254 |
- 1 inch = 25.4 millimetres
- 1 millimetre = 0.0393 inch
- 1 metre = 1,000,000 microns
- 1 micron = 0.000039 inch
Area and Volume Conversion
To convert: | ||
Square inches to square millimetres | Multiply by | 645.16 |
Square inches to square decimetres | Multiply by | 0.064516 |
Square decimetres to square inches | Multiply by | 15.50 |
Square millimetres to square inches | Multiply by | 0.00155 |
Cubic inches to cubic centimetres | Multiply by | 16.3871 |
Cubic centimetres to cubic inches | Multiply by | 0.061024 |
Rules Relating to Circles
- The circumference of a circle is the diameter x 3.1416.
- The diameter of a circle is the circumference multiplied by .31831.
- The area of a circle is the diameter x itself x .7854.
- A circle is .7854 times as heavy as a square of the same size. The loss in cutting a circle from a square is .2146 of the weight of the square.
Stone Conversions
Carat Size | Round Shape MM | Carat Size | Round Shape MM | Carat Size | Round Shape MM | ||
.005 | 1.0 | .11 | 3.1 | .40 | 4.8 | ||
.01 | 1.3 | .12 | 3.2 | .50 | 5.2 | ||
.015 | 1.5 | .14 | 3.3 | .60 | 5.4 | ||
.02 | 1.7 | .15 | 3.4 | .65 | 5.6 | ||
.025 | 1.8 | .16 | 3.5 | .75 | 5.8 | ||
.03 | 2.0 | .17 | 3.6 | .80 | 6.0 | ||
.035 | 2.1 | .18 | 3.7 | 1.00 | 6.5 | ||
.04 | 2.2 | .20 | 3.8 | 1.25 | 7.0 | ||
.05 | 2.4 | .22 | 3.9 | 1.33 | 7.2 | ||
.06 | 2.5 | .23 | 4.0 | 1.50 | 7.4 | ||
.07 | 2.7 | .25 | 4.1 | 1.75 | 7.8 | ||
.08 | 2.8 | .30 | 4.2 | 2.00 | 8.2 | ||
.09 | 2.9 | .33 | 4.4 | 2.50 | 8.8 | ||
.10 | 3.0 | .38 | 4.6 | 3.00 | 9.4 |
Fineness of Gold (Karats)
9K | .3750 | 17K | .7083 | |
10K | .4167 | 18K | .7500 | |
11K | .4583 | 19K | .7917 | |
12K | .5000 | 20K | .8333 | |
13K | .5417 | 21K | .8750 | |
14K | .5833 | 22K | .9167 | |
15K | .6250 | 23K | .9583 | |
16K | .6667 | 24K | 1.000 |
Wire and Drill Sizes
B&S | mm | Inches Thou. | Inches Fractions | Drill Size | B&S | mm | Inches Thou. |
Inches Fractions | Drill Size | |
0 | 8.5 | .325 | 21/64 | 16 | 1.29 | .050 | 54 | |||
1 | 7.35 | .289 | 9/32 | 17 | 1.15 | .045 | 3/64 | 55 | ||
2 | 6.54 | .258 | 1/4 | 18 | 1.02 | .040 | 56 | |||
3 | 5.83 | .229 | 7/32 | 1 | 19 | .912 | .036 | 60 | ||
4 | 5.19 | .204 | 13/64 | 6 | 20 | .813 | .032 | 1/32 | 65 | |
5 | 4.62 | .182 | 3/16 | 15 | 21 | .724 | .029 | 67 | ||
6 | 4.11 | .162 | 5/32 | 20 | 22 | .643 | .025 | 70 | ||
7 | 3.67 | .144 | 9/64 | 27 | 23 | .574 | .023 | 71 | ||
8 | 3.26 | .129 | 1/8 | 30 | 24 | .511 | .020 | 74 | ||
10 | 2.59 | .102 | 38 | 25 | .455 | .018 | 75 | |||
11 | 2.30 | .090 | 3/32 | 43 | 26 | .404 | .016 | 1/64 | 77 | |
12 | 2.05 | .080 | 5/64 | 46 | 27 | .361 | .014 | 78 | ||
13 | 1.83 | .072 | 50 | 28 | .330 | .013 | 79 | |||
14 | 1.63 | .064 | 1/16 | 51 | 29 | .279 | .011 | 80 | ||
15 | 1.45 | .057 | 52 | 30 | .254 | .010 |
Ring Size
Size | Inside Diameter Inch |
Inside Diameter mm |
Size | Inside Diameter Inch |
Inside Diameter mm |
|
1 | .486 | 12.344 | 7 1/2 | .694 | 17.628 | |
1 1/2 | .502 | 12.751 | 8 | .710 | 18.034 | |
2 | .518 | 13.157 | 8 1/2 | .7265 | 18.453 | |
2 1/2 | .534 | 13.564 | 9 | .743 | 18.872 | |
3 | .550 | 13.970 | 9 1/2 | .759 | 19.279 | |
3 1/2 | .566 | 14.376 | 10 | .778 | 19.761 | |
4 | .582 | 14.783 | 10 1/2 | .794 | 20.168 | |
4 1/2 | .598 | 15.189 | 11 | .811 | 20.599 | |
5 | .6141 | 15.597 | 11 1/2 | .8271 | 21.008 | |
5 1/2 | .6300 | 16.002 | 12 | .843 | 21.412 | |
6 | .6455 | 16.396 | 12 1/2 | .859 | 21.819 | |
6 1/2 | .662 | 16.815 | 13 | .875 | 22.225 | |
7 | .678 | 17.221 |
Standard Reference Chart for Ring Size Conversions
US Size | Dia. -inch | Dia. in MM | Metric -MM | British | French | German | Japanese | Swiss |
0000 | .390 | 9.91 | - | |||||
00 | .422 | 10.72 | - | |||||
0 | .454 | 11.53 | - | |||||
1/2 | .474 | 11.95 | A | |||||
3/4 | .482 | 12.18 | A 1/2 | |||||
1 | .487 | 12.37 | 38.9 | B | 1 | |||
1 1/4 | - | 12.60 | 39.6 | B 1/2 | ||||
1 1/2 | .503 | 12.78 | 40.2 | C | ||||
1 3/4 | - | 13.00 | 40.8 | C 1/2 | ||||
2 | .520 | 13.21 | 41.5 | D | 41 1/2 | 13 1/2 | 2 | 1 1/2 |
2 1/4 | - | 13.41 | 42.1 | D 1/2 | - | - | ||
2 1/2 | .536 | 13.61 | 42.7 | E | 42 3/4 | 13 3/4 | 3 | 2 3/4 |
2 3/4 | - | 13.83 | 43.4 | E 1/2 | - | - | ||
3 | .553 | 14.05 | 44.0 | F | 44 | 14 | 4 | 4 |
3 1/8 | - | 14.15 | 44.3 | F 1/2 | - | - | ||
3 1/4 | - | 14.25 | 44.6 | - | - | - | ||
3 3/8 | - | 14.36 | 44.9 | G | 45 1/4 | - | 5 | 5 1/4 |
3 1/2 | .569 | 14.45 | 45.2 | - | - | 14 1/2 | ||
US Size | Dia. -inch | Dia. in MM | Metric -MM | British | French | German | Japanese | Swiss |
3 5/8 | - | 14.56 | 45.6 | G 1/2 | - | 6 | ||
3 3/4 | - | 14.65 | 45.9 | H | 46 1/2 | 6 1/2 | ||
4 | .585 | 14.86 | 46.5 | H 1/2 | - | 15 | 7 | |
4 1/4 | - | 15.04 | 47.1 | I | 47 3/4 | 7 3/4 | ||
4 1/2 | .601 | 15.27 | 47.8 | I 1/2 | - | 15 1/4 | 8 | |
4 5/8 | - | 15.40 | 48.1 | J | 49 | 15 1/2 | 9 | |
4 3/4 | - | 15.53 | 48.4 | - | - | |||
5 | .618 | 15.70 | 49.0 | J 1/2 | - | 15 3/4 | 9 | |
5 1/8 | - | 15.80 | 49.3 | K | 50 | 10 | ||
5 1/4 | - | 15.90 | 49.6 | - | - | |||
5 3/8 | - | 16.0 | 50.0 | K 1/2 | - | 10 | ||
5 1/2 | .634 | 16.10 | 50.3 | L | 51 3/4 | 16 | 11 3/4 | |
5 3/4 | - | 16.30 | 50.9 | - | - | |||
5 7/8 | - | 16.41 | 51.3 | L 1/2 | - | |||
6 | .650 | 16.51 | 51.5 | M | 52 3/4 | 16 1/2 | 12 | 12 3/4 |
6 1/4 | - | 16.71 | 52.2 | M 1/2 | - | |||
6 1/2 | .666 | 16.92 | 52.8 | N | 54 | 17 | 13 | 14 |
6 3/4 | - | 17.13 | 53.4 | N 1/2 | - | |||
US Size | Dia. -inch | Dia. in MM | Metric -MM | British | French | German | Japanese | Swiss |
7 | .683 | 17.35 | 54.0 | O | 55 1/4 | 17 1/4 | 14 | 15 1/4 |
7 1/4 | - | 17.45 | 54.7 | O 1/2 | - | |||
7 1/2 | .699 | 17.75 | 55.3 | P | 56 1/2 | 17 3/4 | 15 | 16 1/2 |
7 3/4 | - | 17.97 | 55.9 | P 1/2 | - | |||
8 | .716 | 18.19 | 56.6 | Q | 57 3/4 | 18 | 16 | 17 3/4 |
8 1/4 | - | 18.35 | 57.2 | Q 1/2 | - | |||
8 1/2 | .732 | 18.53 | 57.8 | - | - | 18 1/2 | 17 | |
8 5/8 | - | 18.61 | 58.4 | R | 59 | 19 | ||
8 3/4 | - | 18.69 | 58.4 | - | - | |||
8 7/8 | - | 18.80 | 59.0 | R 1/2 | - | |||
9 | .748 | 18.89 | 59.1 | - | - | 19 | 18 | |
9 1/8 | - | 19.10 | 59.4 | S | 60 1/4 | 20 1/4 | ||
9 1/4 | - | 19.22 | 59.7 | - | - | |||
9 3/8 | - | 19.31 | 60.0 | S 1/2 | - | |||
9 1/2 | .764 | 19.41 | 60.3 | - | - | 19 1/2 | 19 | |
9 5/8 | - | 19.51 | 60.6 | T | 61 1/2 | 21 1/2 | ||
9 3/4 | - | 19.62 | 60.9 | - | - | |||
10 | .781 | 19.84 | 61.6 | T 1/2 | - | 20 | 20 | |
US Size | Dia. -inch | Dia. in MM | Metric -MM | British | French | German | Japanese | Swiss |
10 1/4 | - | 20.02 | 62.2 | U | 62 3/4 | 21 | 22 3/4 | |
10 1/2 | .797 | 20.20 | 62.8 | U 1/2 | - | 20 1/4 | 22 | |
10 5/8 | - | 20.32 | 63.1 | V | 63 | 23 3/4 | ||
10 3/4 | - | 20.44 | 63.5 | - | - | |||
11 | .814 | 20.68 | 64.1 | V 1/2 | - | 20 3/4 | 23 | |
11 1/8 | - | 20.76 | 64.3 | W | 65 | 25 | ||
11 1/4 | - | 20.85 | 64.7 | - | - | |||
11 3/8 | - | 20.94 | 65.0 | W 1/2 | - | |||
11 1/2 | - | 21.08 | 65.3 | - | - | 21 | 24 | |
11 5/8 | .830 | 21.18 | 65.7 | X | 66 1/4 | 26 1/4 | ||
11 3/4 | - | 21.24 | 66.0 | - | - | |||
11 7/8 | - | 21.30 | 66.3 | X 1/2 | - | |||
12 | .846 | 21.49 | 66.6 | Y | 67 1/2 | 21 1/4 | 25 | 27 1/2 |
12 1/4 | - | 21.69 | 67.2 | Y 1/2 | - | |||
12 1/2 | .862 | 21.89 | 67.9 | Z | 68 3/4 | 21 3/4 | 26 | 28 3/4 |
12 3/4 | - | 22.10 | 68.5 | Z 1/2 | - | |||
13 | .879 | 22.33 | 69.1 | - | - | 22 | 27 | |
US Size | Dia. -inch | Dia. in MM | Metric -MM | British | French | German | Japanese | Swiss |