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.

Size	Thickness, in Stub’s gauge	Thickness, S.W.G.	lbs/ft super
IC	30	30	0.514
IX (1X)	28	27	0.643
IXX (2X)	27	26	0.739
IXXX (3X)	26	25	0.836
IXXXX (4X)	25	23	0.932
DC		27	0.664
DX		24	0.854
DXX		23	0.996
DXXX		22	1.138
DXXXX		21	1.281
SDC		26	0.733
SDX		25	0.825
SDXX		24	0.916
SDXXX		23	1.008
SDXXXX		22	1.100

Size

DXX

DXXX

DXXXX

14×10

225
108 lbs

225
136 lbs

225
156 lbs

225
176 lbs

14×20

20×20

17×12½

17×25

15×11

30×21

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.