{"id":1900,"date":"2014-06-01T14:35:14","date_gmt":"2014-06-01T06:35:14","guid":{"rendered":"http:\/\/www.tongtuning.com\/wordpress\/?p=1900"},"modified":"2021-09-17T13:43:00","modified_gmt":"2021-09-17T05:43:00","slug":"bow-drills","status":"publish","type":"post","link":"https:\/\/www.tongtuning.com\/wordpress\/1900","title":{"rendered":"Bow Drills"},"content":{"rendered":"
The Erlandsens<\/a> made the drill stock that became the standard of the piano industry.<\/h5>\n
This ancient tool, which was depicted in Egyptian hieroglyphs, is almost as old as the invention of fire, as the first versions of it were used to start fires and to drill holes in stones and beads.\u00a0 They were driven by a bow held in the opposing hand, and, as a drill, were capable of producing precision work by skilled and practiced craftsmen. The bow was moved back and forth, in a steady reciprocal motion, somewhat like a cellist might play.<\/h5>\n
Samuel Wolfenden, a British pianomaker and author of \u201cA Treatise on the Art of Pianoforte Construction,\u201d (1927) wrote about the application of bow drills in piano work:\u00a0 \u201c…the old stock, used with a weak bow for bridges and a strong one for wrest-planks, is superior.\u00a0 For use with the bow, the drills for bridge pins should be made of steel wire, with rather long points, and half the diameter filed away, leaving a cutting edge on each side.\u00a0 Made thus, they bring out all the core, which–if the drill is stuck into a piece of hard soap–falls away, and the point is cooled and lubricated for the next hole.<\/h5>\n
For drilling wrest-pin holes, thin \u201cquill\u201d bits are best.\u00a0 Very accurate fitting is needed, and it is wise to have a selection with very small differences in the diameters of the resultant holes, so that differences in the hardness of the wrest-planks (often considerable) may be met, and also small differences in the gauge of wrest-pins for it frequently happens that the pins are not quite of the nominal diameter.\u00a0 It is astonishing how much difference there can be in the tightness of wrest-pins arising from either of these causes.\u201d<\/h5>\n
In North America, bow drills were traditionally used for relatively delicate drilling, such as making holes for the bridge pins, and there are about 470 holes per piano, for that task alone!\u00a0 Many of the smaller holes for various screws were also made with this tool. Precision\u00a0 drilling was critical before 1850, because the screws lacked a point, or gimlet, to aid in starting in the drilled hole, but this predates Erlandsen\u2019s bow drill, which was introduced when Napoleon Erlandsen set up shop in 1863.<\/h5>\n

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