A search of the art uncovered the following patents showing various ways of clamping workpieces in a fixture. U.S. Pat. Nos.:
666,905; 766,403; 1,027,419; 1,438,250; 1,740,934; 1,883,993; 2,060,158; 2,337,528; 2,407,985; 2,415,037; 2,427,712; 2,472,022; 2,639,491; 2,873,628; 2,946,583; 3,020,998; 3,024,184; 3,395,911; 3,424,319; 3,727,906; 3,802,688; 3,908,813.
USPTO Backgrounds
USPTO Backgrounds