Note 148 — LAKE DWELLINGS. PART I. (continued 3)
Reading edition
Sir Denham Jephson Norreys, in a Paper contributed to the R. Hist, and Arch. Asso. Ireland (Journal, vol. iv., pp. 278-79), thus explains the original process of riveting:—
“1st. Prepare a wooden core, or mandril, of the size and form of the inside of the trumpet.
“2ndly. Place the strap of bronze to hold the rivets in the centre of its inner surface.
“3rdly. Cut the plate of bronze which is to form the trumpet to such a size that, when folded on the core, the edges may meet accurately on the centre of the bronze strap: hold all together by solder, or by any other means—perhaps coils of wire may have been used.
“4thly. Drill the holes for the rivets, countersinking them on the outside. See Plate XXIX., fig. 1.
“5thly. Remove the wooden core.
“6thly. By means of a cleft stick (or other contrivance) insert the rivets from the inside, outwards.
“7thly. As each rivet passes through to the surface it is to be drawn up as tightly as possible; the shank is to be bent back, or held up by any other means, so that the head of the rivet shall not be allowed to fall.
“8thly. Having inserted all the rivets, insert a metal core, or mandril, fitting the interior with great exactness.
“9thly. Complete the riveting from the outside, the metal core preventing the rivet-heads from being disturbed, and allowing the countersunk portion of the hole to be securely filled by a portion of the shank.
“10thly. Remove the metal core. The trumpet is now ready to be burnished off.
“After writing the above, it occurred to me that I had neglected to inquire how the inner strap was to be held in its place for the insertion of the rivets. Ordinary solder could not have been used, as none appears between the strap and the plates. It might, perhaps, have been effected by a slow removal of the wooden core, and by the insertion, from the smaller end of temporary rivets or fastenings, as the core was being pushed forward; by such means at least half of the length of the strap could be firmly held in its place.”