English: A complete cast copper-alloy Roman lock bolt, dating from c. AD 43-410. The lock bolt is rectangular in plan and cross-section with a central rectangular openwork panel of four sub-triangular apertures, flanked by two different protruding bars. One bar is rectangular and thin, extending perpendicularly from the upper edge of the openwork panel on one side. The other bar tapers parallel to the panel and is rectangular in plan and sub-triangular in cross-section; the bar tapers from is widest point near the openwork panel to a thin straight edge where it terminates. The lock bolt is of an even medium green patina with some possible light iron staining on the inside of the openwork panel. It measures 56.7 mm long, 12 mm wide (at central panel) and 6.2 mm thick (central panel); it weighs 11.8 grams.

Lock bolts form part of a tumbler lock. The key would slide into the cut-outs of the panel and release the lock when rotated. A similar lock bolt is illustrated in Wilson (2002), 'Cataractonium. Roman Catterick and its hinterland', p 68, no. 239; see also: Crummy 1983: 124, nos. 4133-4136. Recorded parallels on the PAS database include BH-1CA656 and BH-1C4BE8.