Historic Doors and Furniture
Dating historic chests and doors cannot usually be sampled in the normal manner, due to the small size of the timbers concerned. The surface of the timber are often too abraded or damaged to allow the rings to be accurately measured through photography or impression, and where cleaning the surface would cause unacceptable visual damage to the timberwork, a micro-borer is used to extract the samples. This system was initially developed for work on the medieval doors at the Tower of London, commissioned by the Historic Royal Palaces Agency. This consists of a small 8mm outside diameter hollow drill bit which extracts a 5mm diameter core. The drill bit is cooled and cleared of dust with the aid of compressed air which is channelled through the inside of the cutting tube and clears the waste from around the outside of the bit. By mounting the drill in a travelling carriage mounted on a large press or bench and accurately aligned to the surface of the timber, the drill can be used to bore through a number of boards as thin as 15mm thick and as wide as 1000mm or longer. The drill can also be used free-hand on large doors by fixing an offest guide to the surface. Thus a number of boards can be drilled in succession with the need to make only a single hole. The thin cores are then glued to grooved mounts and prepared in the normal manner.
Fine quality doors and furniture rarely have sapwood, therefore it is important that as many panels or boards can be sampled to allow the best interpretation of felling date range to be produced.
Through using this and a variety of other techniques, a number of historic doors and chests have been successfully dated. These include:
Wells Cathedral - Cope Chest and treasury doors