The Way Tubes for Artist's Colors are Made.

Scientific American 9, 26.8.1865

MESSRS. EDITORS: — As a recent number of the SCIENTIFIC AMERICAN indicates a desire on the part of a subscriber to obtain information respecting the process of manufacturing the small tin tubes used for artists colors and a variety of other purposes, I have forwarded the following description of the process as carried out in England under Rand's Patent, and called "Rand's Patent Collapsible Tubes."

"These thin tubes are closed at the one end by a convex disk with a projecting screw; the screw being perforated for the expulsion of artist's colors or other matters inclosed in the vessels. They were first drawn as tubes and the ends cast and soldered in, but the entire vessel is now made by only two blows, in dies of appropriate kinds. By one blow of a screw press, a thick circular disk of tin of the external diameter of the intended vessel is punched out, made concave, and perforated with a central hole, somewhat like a washer for machinery. By a second blow, the blank or button is converted into the finished tube. The bottom tool is a mold with a shal-low cylindrical cavity of the same diameter as the button of tin, and terminating in a hollow screw. The upper tool is a cylinder exceeding the length of the tube, and with a small taper spindle of the diam eter of the hole. The cylinder is just so much smaller than the mold as to leave an annular space equal to the intended thickness of the tube. The very sort, ductile tin, when submitted to great pressure in the concentrated space within the mold, follows the laws of liquids, and may be said literally to flow through the annular crevice, and up the cylindrical mandrel; as indeed the formation of the tube appears to be instantaneous, and is a beautiful example, both of true principle and accurate workmanship, in the means employed.

The tube is released from the mold, first, by the ascent of the cylinder, which leaves the tube behind; and the screwed extremity of the mold is then driven up by a cam and lever from below, and the screwed dies, being divided on their diameter, instantly fall away from the vessel thus elegantly produced by a mode which was only attained after repeated variations in the process, respectively secured by patents. Small tubes are thus made in screw presses, and large tubes in hydrostatic presses of proportionate strength."

The above description is at your service if of any value.

- ABEL S. CHAPPELL.
Brooklyn, Aug. 50, 1865.