Manufacture custom tools used in factories and plants.
Sets up and operates jig borer to perform machining operations, such as boring, drilling, reaming, and counterboring holes in metal workpieces, such as jigs, fixtures, gauges, and dies, according to specifications, applying knowledge of metal properties, tooling, and precision machining: Studies machining instructions, such as job order, blueprint, process sheet, or layout on workpiece to determine dimensional and finish specifications, sequence of operation, setup, and tooling requirements. Lifts workpiece either manually or with hoist onto machine table. Positions and secures workpiece on table with bolts, clamps, shims, or other holding devices, using machinist’s handtools. Verifies parallelism of reference lines on workpiece to axis of table motion, using dial indicator mounted in spindle. Establishes zero reference point on workpiece, such as at intersection of two edges or over hole location. Turns handwheel to adjust machine table to align spindle over point, using dial indicator. Sets table-position dial at zero; measures all machining locations from this zero point. Selects and sets cutting speeds, feed rates, depth of cut, and cutting tool according to machining instructions or knowledge of metal properties. Installs tool in spindle. Turns handwheels to lower tool to workpiece and engages automatic feed. Turns valve and directs flow of coolant or cutting oil over cutting area. Verifies location and dimensions of holes, using measuring instruments, such as dial indicator, gauge blocks, telescoping gauge and internal micrometer. Works to tolerances as close as plus or minus 0.0001 inch. May work only from blueprint. May lay out reference lines and machining locations on workpiece, according to blueprint, using layout tools, such as rule, divider, and scriber, applying knowledge of shop mathematics and layout techniques. May fasten workpiece in holding fixture mounted on machine table or clamp jig or template in position on workpiece. May operate machine manually throughout first piece operation to verify accuracy of setup. May sharpen tools on bench grinder.