Edinburgh Encyclopaedia, Vol. 8

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1832 edition. Excerpt: ...for the swelling of the plate inthe fire,-which is a circumstance that invariably happens. The proper die being chosen, place one of the pieces of copper on that side of the die which has the smallest diameter, and as nearly in the centre as possible; lay the die, with the oopper upon it, fiat on a table or board, and the round ended punch, Fig. 2. being put on the centre, press it down and wriggle it round till the end of itis forced as far as it can go into the centre hole of the die. The copper is then to be taken off, and the bulge thus formed must be filed nearly through. Let the copper then be placed on the die in the same manner as before, and the round broach gently thrust-through the centre hole, till it fits it nearly tight to the die. When this is done, holding the die and copper in the left hand, with the die upwards, let the copper be cut as nearly round as possible, leaving it about-512,-El'"lht_:)f is may be best accomplished by holding the scissars a lit-tle aslant, till the desired breadth is obtained. The die, with the copper u-ppermostfis then to be laid on the work board, and gently rubbed or burnished over with the round broach, till the copper lies quite smooth and flat on the die. Hold the die and the copper firmly in i the left hand, and having the broach in the,right, bur nish that part of the copper which extends beyond the edge of the die, which is best done by rubbing the broach round the copper, and pressing it close to the edge of the die. The copper is now to be taken off the die, and the edge or rim thus formed must be finished by filing it till it is equal on every side. The centre hole must be filed a little to take off the ragged parts, but it must not be made so low as the edge; and the bur...