A Wealden Cannon-Boring Bar
| Autor: | D. S. Butler, C. F. Tebbutt |
|---|---|
| Rok vydání: | 1975 |
| Předmět: | |
| Zdroj: | Post-Medieval Archaeology. 9:38-41 |
| ISSN: | 1745-8137 0079-4236 |
| DOI: | 10.1179/pma.1975.002 |
| Popis: | EARLY IN 1975 meinbers of the Wealden Iron Research Group,in the course of their survey of Wealden water-powered iron-working sites, visited Strean1. Mill, Chiddingly, Sussex (N.G. TQ555155). Here we were shown a long wrought iron bar which was immediately recognized as a cannon boring bar with three of its original four steel cutters still intact, in surprisingly good condition.I As the owners wished it to be conserved and placed in a Inuseum it was later removed manually, with some difficulty, to the road, and was found to be I I feet (3· 53 m.) long and to 'Yeigh 190 lb. (85·72 kg.) (Plates Xla and XIb). The garden, just behind the surviving corn mill buildings, where the bar was found, consists of very black charcoal impregnated soilz containing much glassy blast furnace slag. With the bar were also found' some short lengths of toothed iron rack and a 'riser' from a cannon-ball casting. Slag was also found scattered on the outer slope of the dam, that once held up the furnace pond, and on the field below. With it were slnall pieces of clay casting moulds. It was decided to clean and restore the bar by electrolytic reduction and at the end of about two weeks' treatment the boring head was practically free of corrosion products and it was found possible to extract one of the cutters to enable a sample to be taken for analysis of the steel. The approximate size of the cutter was 2· 6X I· 5X •6 inches (65X 38X 14 mnl.), and it had been fixed into its slot in the boring head by means of a thin iron wedge. The tool itself needs little description as most of its features are illustrated in the drawing (FIG. I). The rod is octagonal and slightly twisted, perhaps through working in a clockwise direction. It is a fine example of precision forging in wrought iron. The rectangular tang is obviously designed to fit into a similarly shaped socket in the hub or axle of a water-wheel, secured by a cotter pin through a hole, 4 inches (102 mm.) from the end of the tang. This hole was found to be slightly tapered from I to ·9 inch (25 to 23 mm.). The great length and weight of the bar would seem to demand the support of a bearing, but the tool itself gives no clue to what forin this might have taken. A metal ring, clamped on to the octagonal shaft, might have run in a support bearing that could be moved as the bar passed into the cannon barrel. Again such a ring, in |
| Databáze: | OpenAIRE |
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