Metal-work; a handbook for teachers and students (1914)
Adam, Hugh M. [from old catalog], Evans, James Humphrey, [from old catalog] joint author · New York, Longmans, Green and co.; London, E. Arnold · leaf 137
the forge, and hold the tap inside untilheated sufficiently to charge the bright metal uniformly to adeep straw colour, and then cool out by plunging into water. The neck and squareshoulder must now betempered to light blue byholding in a bunsen flame.In a first lesson ontapping, a studentshould… … Fig. 83, — Section of Whitwoeth TapSHOWING Backing. The most common causes of breakage are— 1. The application of unnecessary force. 2. Unconscious bending by applying unequal force to thetwo handles of the wrench. When a broken tap cannot be extracted by pliers, it mustbe heated to draw the…
Metal-work
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![An illustration from Nicolai Copernici Torinensis De reuolutionibus orbium coelestium, libri VI : Habes in hoc opere iam recens nato, & aedito, studiose lector, motus stellarum, tam fixarum, quàm erraticarum, cum ex ueteribus, tum etiam ex recentibus obseruationibus restitutos: & nouis insuper ac admirabilibus hypothesibus ornatos. Habes etiam tabulas expeditissimas, ex quibus eosdem ad quoduis tempus quàm facillime caculare poteris. Igitur eme, lege, fruere. [Line in Greek] (1543)](https://img.insideoutlibrary.com/img/200/ia-nicolaicopernici00cope-306-199.webp)
