tinplate

The thickness of the coating of tinplate was described by specifying the mass in pounds of tin per “base box” (or “basis box” in Great Britain).

Great Britain

In Britain, the basis box was a quantity of 112 sheets, each 14 inches by 10 inches.

Designation No. of
sheets
per box
Size,
inches
Weight
per box,
pounds
Thickness,
in
Stub’s gauge
Thickness,
S.W.G.
lbs/sq. ft
IC 225 13¾ × 10 112 30 30 0.514
2C 225 13¼ × 9¾ 105      
3C 225 12¾ × 9½ 98      
HC 225 13¾ × 10 119      
HX 225 13¾ × 10 147      
IX (1X) 225 13¾ × 10 140 28 27 0.643
2 X 225 13¼ × 9¾ 133 27 26 0.739
3 X 225 12¾ × 9½ 126 26 25 0.836
1 XX 225 13¾ × 10 161      
1 XXX 225 13¾ × 10 182      
1 XXXX 225 13¾ × 10 203 25 23 0.932
D C 100 16¾ × 12½ 105   27 0.664
D X 100 16¾ × 12½ 126   24 0.854
D XX 100 16¾ × 12½ 147   23 0.996
D XXX 100 16¾ × 12½ 168   22 1.138
D XXXX 100 16¾ × 12½ 189   21 1.281
S D C 200 15  × 11 168   26 0.733
S D X 200 15  × 11 189   25 0.825
S D XX 200 15  × 11 210   24 0.916
S D XXX 200 15  × 11 231   23 1.008
S D XXXX 200 15  × 11 252   22 1.100
Wasters 200 13¾ × 10 126      
TT 450 13¾ × 10 112      
X TT 450 13¾ × 10 126      

John Thomas Hurst
A Handbook of Formulæ, Tables, and Memoranda for Architectural Surveyors and Others Engaged in Building.
London: E. and F. N. Spon, 1865.
Page 96.

United States

Tin plate was customarily supplied in 14 inch by 20 inch sheets, in boxes of 112 sheets. The thinnest sheets, called “taggers,” came in two thicknesses, 34 (150 sheets in a box) and 38 (225 sheets in a box). Kent (1916) describes the varieties of tin plate succinctly:

Tin Plates are made of soft sheet steel coated with tin, and are called in the trade “coke” or “charcoal” plates according to the weight of coating. These terms have survived from the time when the highest quality of plate was made from charcoal-iron, while the lower grades were made from coke-iron. Consequently, plates today [1916] with the lighter coatings are known as coke-plates, and are used for tin cans, etc. The various grades of charcoal-plates are designated by the letters A to AAAAA, the latter having the heaviest coating and the highest polish. There is one other brand made with a heavier coating than 5A, which is especially adapted for nickel-plating. The unit of value and measurement of tin plates is the “base-box,” which will hold 112 sheets of 14 × 20 in. plate, or 31360 sq.in of any size. Plates lighter than 65 lb. per base box (No. 30 gage) are known as taggers tin.²

The following table presents all the American tin plate designations of which we are aware. It does not necessarily represent only designations in use at one particular time.

Trade
term
Nearest
wire gauge
Approx.
thickness
in inches
Weight
per square foot
in pounds
Weight
of box of 112
14 × 20 inch sheets
55 38 0.0060 0.2525 55
60 37 0.0066 0.2756 60
65 36 0.0071 0.2987 65
70 35 0.0077 0.3212 75
75 34 0.0082 0.3444 75
80 33 0.0088 0.3675 80
85 32 0.0093 0.3900 85
90 31 0.0099 0.4131 90
95 31 0.0104 0.4362 95
100 30½   0.459 100
ICL 31 0.0110 0.4594 100
IC 30 0.0117 0.490 107
  30 0.0123 0.514 112
118 29 0.0130 0.542 118
  29 0.0135 0.565 123
IX 28 0.0148 0.620 135
IXL 28 0.0141 0.588 128
DC 28 0.0153 0.638 139
2X 27 0.0170 0.711 155
2XL 27 0.0163 0.679 148
3X 26 0.0192 0.804 175
3XL 26 0.0184 0.771 168
DX 25 0.0198 0.827 180
4X 25 0.0214 0.895 195
4XL 25 0.0206 0.863 188
D2X 24 0.0231 0.964 210
5X 24 0.0236 0.987 215
6XL 24 0.0250 1.047 228
6X 23 0.0258 1.079 235
D3X 23 0.0264 1.102 240
7XL 23 0.0272 1.139 248
7X 23 0.0280 1.171 255
8XL 22 0.0294 1.231 268
D4X 22 0.0296 1.239 270
8X 22 0.0302 1.263 275

 

1. W.E. Hoare, E.S. Hedges and B.T.K. Barry.
The Technology of Tinplate.
London: Edward Arnold, 1965.

2. William Kent.
The Mechanical Engineers' Pocket-Book. A Reference-Book of Rules, Tables, Data and Formulae. 9th ed.
New York: John Wiley and Sons, 1916.

Page 192.

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