page_title: Chuck (engineering)
section_title: History
hierarchical_section_title: Chuck (engineering) / History
caption_attribution_description: English: Jacobs taper is visible at the top of the chuck
context_page_description: A chuck is a specialized type of clamp used to hold an object with radial symmetry, especially a cylinder. In drills and mills it holds the rotating tool whereas in lathes it holds the rotating workpiece. On a lathe the chuck is mounted on the spindle which rotates within the headstock. For some purposes an additional chuck may be mounted on the non-rotating tailstock.
  Many chucks have jaws, that are arranged in a radially symmetrical pattern like the points of a star. The jaws are tightened up to hold the tool or workpiece. Often the jaws will be tightened or loosened with the help of a chuck key, which is a wrench-like tool made for the purpose. Many jawed chucks, however, are of the keyless variety, and their tightening and loosening is by hand force alone. Keyless designs offer the convenience of quicker and easier chucking and unchucking, but have a lower gripping force to hold the tool or workpiece, which is potentially more of a problem with cylindrical than hexagonal shanks. Collet chucks, rather than having jaws, have collets, which are flexible collars or sleeves that fit closely around the tool or workpiece and grip it when squeezed.
context_section_description: The original forms of workholding on lathes were between-centers holding and ad hoc fastenings to the headstock spindle. The spike-style centers still used on wood lathes represent an ancient method. Ad hoc fastening methods in centuries past included anything from pinning with clenching or wedging; nailing; lashing with cords of leather or fiber; dogging down (again involving pinning/wedging/clenching); or other types. Faceplates have probably been around at least since the era of medieval clock-makers.
  Tooling similar to today's chucks seems likely to have evolved from faceplate work, as workers using faceplates for repetitive work began to envision types of clamps or dogs for the faceplate that could be opened and closed in more convenient ways than repeated total disassembly and reassembly. 
  A chock was originally just a lump of wood.  However, by 1703 it could be "… Chocks, belonging to the Screw-Mandrel".  By 1807 the word had changed to the more familiar 'chuck: "On the end of the spindle … is screwed … a unversal Chuck for holding any kind of work".
  
  In late 1818 or early 1819 the Society for the Encouragement of Arts, Manufactures and Commerce awarded its silver medal and 10 guineas (£10.50 – equivalent to £802 in 2019) to Mr. Alexander Bell for a three jaw lathe chuck:
  The instrument can be screwed into … the mandrel of a lathe, and has three studs projecting from its flat surface, forming an equi-lateral triangle, and are capable of being moved equably to, or from, its centre.
    It is not clear how they were moved "equably" whether by a scroll or some other means.  Later in 1819 the same body awarded a further silver medal to Mr. T. Hack for a four jaw chuck.  In the United States Simon Fairman (1792–1857) developed a recognisable modern scroll chuck as used on lathes.  The patent refers to the technicalities of 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.
caption: The Jacobs type chuck, with three converging splines or jaws, is perhaps the most usual design. This one is tightened with a key, but some types may be sufficiently tightened by hand
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