assembly, he does not claim invention of the scroll ("convolute grooves"). His son-in-law Austin F. Cushman (1830–1914) developed the ideas and sold chucks through his business, Cushman Industries. Jacobs Chuck At the start of the 20th century, Arthur Irving Jacobs developed the modern drill chuck. After bruising his knuckles on one of the old-fashioned spanner adjusted drill chucks, he developed a chuck in which the jaws moved axially in inclined slots. His details the mechanism. The term clearly did not originate with him, but his new type of drill chuck long ago displaced any earlier types that lacked the angled jaw movement and outer sleeve now found on all common drill chucks. Performance evaluation National and international standards are used to standardize the definitions, requirements, and test methods used for the performance evaluation of chucks. Selection of the standard to be used is an agreement between the supplier and the user and has some significance in the design of the chuck. In the United States, ASME has developed the B5.60 Standard entitled Workholding Chucks: Jaw-Type Chucks, which establishes requirements and methods for specifying and testing the performance of workholding chucks used primarily in turning operations. See also Collet Drill bit shank Lathe faceplate Mandrel Mechanical pencil Woodturning Wrench References Bibliography Clamps (tool) Lathes Machine tools Woodworking clamps