The general standard of corks or stoppers, known as the United States standard, is as follows:
| No. | 0 | 3⁄8 | inch | No. | 1 | 7⁄8 | inch. | |||
| “ | 2 | 1⁄2 | “ | “ | 3 | 9⁄16 | “ | |||
| “ | 4 | 5⁄8 | “ | “ | 5 | 11⁄16 | “ | |||
| “ | 6 | 3⁄4 | “ | “ | 7 | 13⁄16 | “ | |||
| “ | 8 | 7⁄8 | “ | “ | 9 | 15⁄16 | “ | |||
| “ | 10 | 1 | “ | “ | 11 | 1 | 1⁄16 | “ | ||
| “ | 12 | 1 | 1⁄8 | “ | “ | 13 | 1 | 3⁄16 | “ | |
| “ | 14 | 1 | 1⁄4 | “ | “ | 15 | 1 | 5⁄16 | “ | |
| “ | 16 | 1 | 3⁄8 | “ | “ | 17 | 1 | 7⁄16 | “ | |
| “ | 18 | 1 | 1⁄2 | “ | “ | 19 | 1 | 9⁄16 | “ | |
| “ | 20 | 1 | 5⁄8 | “ | “ | 24 | 1 | 7⁄8 | “ | |
| “ | 22 | 1 | 3⁄4 | “ | “ | 26 | 2 | “ | ||
| Length is generally designated as short, regular, extra long, and the shape as tapered, or straight. | ||||||||||
This classification of necessity applies to the trade and gives a size for almost any character of work there is, though another general classification that is used principally abroad, is as follows:—
Thick corks having more than 31 millimeters[36] in diameter.
Ordinary or commercial, from 25 to 31 millimeters.
Bastard corks, from 23 to 25 millimeters.
Thin corks, having less than 23 millimeters.
These classes of sizes are of course divided again and again by the manufacturers. To this size classification must be added a quality distinction, and this generally takes the same as before described, in sorting the cork-board, grading down from the best which is tawny or pink in color, with a fine texture, free from cracks, stone cells, or other blemishes.
As has been stated, the punch is now employed in most corkwood establishments, but there are still a few who do the work by hand and maintain that the best results are obtained in this manner.
Hand-cut corks or stoppers are used mostly for the high-class wine trade and are a little more expensive than machine cut. There is also a hand machine for shaping corks, which consists of a knife, the blade of which is placed horizontally, joined generally to a piece of wood, to which a back and forward movement is given similar to that of a carpenter’s plane. In moving, the knife turns the square cork, or whatever shape it may be, by a series of belt attachments, and takes off a strip of cork (palilla) more or less thick, according to the distance from the axis of the cork and the edge of the blade; the principle being the same in the power machine, if these are parallel the resulting cork will be cylindrical, and if not, it becomes conical.
The standard size stopper is the prime use to which corkwood has been put, and in the making of it the best material is used; this material coming in varying thicknesses, it sometimes is difficult to secure enough for making “champagnes,” so some manufacturers produce a stopper that answers the requirements by fastening two pieces of thin superfine corkwood together with a rubber cement made by dissolving pure Para rubber in disulphide of carbon, which makes a very good binder and not lessening the quality service to any appreciable degree.
After the corks are cut, the ends are not always as even and as smooth as desired, so they are taken to a sandpaper wheel which revolves very rapidly in an upright position, and against this the corks are held for a few seconds until the surface becomes smooth and straight, the dust created being collected and used in various ways. (See “[Waste Utilization].”)