Drill Press

Overview

A drill press is a fixed machine that holds a drill bit in a powered spindle and drives it straight down into a clamped workpiece. Because the spindle runs in a rigid head rather than a hand, holes come out square to the table, on location, and to a set depth every time. This unit is a floor-standing 16-inch pillar drill: a ¾-HP induction motor turns a V-belt over stepped pulleys to give twelve spindle speeds from 180 to 2,770 rpm, fast for small bits in wood, slow for large bits in steel.

The machine builds up from the Base & Column, whose cast foot carries a round steel column. The Table Assembly clamps to that column and raises, lowers and tilts to position the work. At the top, the Head Casting casting houses the drive and the feed mechanism. Power runs in through the Power Cord & Wiring to the Switch & Control Board, whose paddle switch carries a no-volt release so the spindle will not restart on its own after a power cut.

How it works

The Induction Motor sits on a pivoting plate at the back of the head. Its shaft carries a cone of V-grooves; a matching cone faces it on the spindle. The Speed-Change Drive sets the ratio: lift the belt guard, move the V-belt to a matched pair of steps, and swing the tension lever to take up slack. A large step on the motor driving a small step on the spindle gives high speed; the reverse gives torque for big holes.

The belt turns the Spindle & Quill Assembly. The spindle is splined, so it keeps turning while it slides up and down inside the quill, a sleeve that runs on bearings in the head bore. Pulling the Feed Handle, a three-spoke lever, rotates a pinion that meshes a rack on the quill and feeds the whole spindle down into the work. Release the handle and a clock-type return spring lifts it back up. The Depth Stop & Gauge is a threaded rod with lock nuts that halts the travel, so a run of parts all get the same hole depth.

At the bottom of the spindle, a Morse taper seats the Jacobs Chuck, a three-jaw keyed Jacobs chuck. Turning the chuck key drives a scroll ring that moves all three hardened jaws inward together, self-centring the bit shank. The operator clamps stock to the slotted table, picks a speed for the material and bit size, sets the depth stop, switches on, and feeds the bit down with the handle.