Verify conformance of machined work to specifications, using measuring instruments, such as calipers, micrometers, or fixed or telescoping gauges. Study machining instructions, job orders, or blueprints to determine dimensional or finish specifications, sequences of operations, setups, or tooling requirements. Select and set cutting speeds, feed rates, depths of cuts, and cutting tools, according to machining instructions or knowledge of metal properties. Install tools in spindles. Change worn cutting tools, using wrenches. Position and secure workpieces on tables, using bolts, jigs, clamps, shims, or other holding devices. Move machine controls to lower tools to workpieces and to engage automatic feeds. Turn valves and direct flow of coolants or cutting oil over cutting areas. Operate single- or multiple-spindle drill presses to bore holes so that machining operations can be performed on metal or plastic workpieces. Establish zero reference points on workpieces, such as at the intersections of two edges or over hole locations. Observe drilling or boring machine operations to detect any problems. Lift workpieces onto work tables either manually or with hoists or direct crane operators to lift and position workpieces. Lay out reference lines and machining locations on work, using layout tools, and applying knowledge of shop math and layout techniques. Perform minor assembly, such as fastening parts with nuts, bolts, or screws, using power tools or hand tools.