Bench or Pillar Drills
Drill Press
OTHER NAMES: Bench drill. pillar drill
SIZE: Drilling capacity in mild steel Jm, Jin.; Depth of throat: 6 to 10in.
MATERIAL: Various
ACCESSORIES: Drill bits. rotary rasps
ATTACHMENTS: Mortising attachment, sanding drum-routing attachment. bulling wheels
USE: To drill holes in various metals
A drill press is more accurate than a hand drill or a portable electric drill A simple attachment will convert an electric drill into a drill press, but special purpose drill presses are sturdier, more powerful machines. Bench-standing drill presses have a heavy cast base to support the column which holds the drill head itself. The base, which can be used as a worktable. is bolted to your workbench. Above the base is another worktable which is clamped to the column. This table can be raised and lowered, pivoted sideways, and in some cases, angled. The base surface is accurately machined flat and has bolt holes for fixing workpieces or special vises to the table.
The drilling head incorporates a rear-mounted motor which drives the spindle through a series of pulley wheels and a drive belt. On top of the motor is a cone pulley, connected by a "V" belt to another, inverted cone pulley on the drive spindle. This system provides various speeds at the chuck. Some models incorporate gear wheels to provide speed changes instead of the pulley and belt system.
The chuck is fitted to the other end of the spindle. Any drill bits suitable for the portable electric drill will fit the press.
The whole mechanism of the drill press is protected by pressed metal covers.
Operating the controls
Select the speed by moving the drive belt. The top position provides the fastest speed, the low position the slowest. Pull up or down on one side of the belt while turning the pulleys by hand to move the belt to the required position. To slacken the belt, move from the large pulley to the small
Metal and other hard materials need slow speeds, while a fast speed will be required for a clean finish on lumber but check with the manufacturer's instructions for precise information.
Insert the drill bit into the chuck and tighten the jaws with a chuck key. The work should be just below the point of the drill bit. Adjust the worktable by slackening the clamp lever and moving the table by hand, lining up the centre hole with the drill bit. Tighten the clamp to secure the table. If you do not need the table swing it to one side. Lower the spindle and lock it in the desired position with the feed lock.
The depth of the hole is limited by the depth gauge. Align the tip of the drill with a marked line on the outside of the work and run one nut on the gauge down to meet the stop. Use the second nut as a lock nut against the first.
Lowering the spindle
Pull on the feed adjustment lever, which is spring-loaded to return to the rest position.
Holding the work
Hold the work securely. If the bit catches in the work, it will spin it. Be particularly careful when drilling metal, which has a greater tendency to catch. Always clamp it either in a machine vise or to the work-table. Long pieces c\( wood can be held against the column. Use a fence for shorter pieces, or clamp them to the table.
Using a fence
For shorter wood pieces, clamp a guide to the table. If several holes are to be drilled in a line, a fence is better than clamping as the work can then be easily moved along.
Holding round stock
"V" blocks will safely hold pipe or round stock.
Drilling through the work
Clamp a sheet of plywood between it and the table to prevent the bit breaking out the underside of the work as it emerges. Alternatively, as soon as the drill point exits, turn the work over and drill from the other side.
Mortising attachment
A mortising attachment can be bolted just above the chuck. A square hollow chisel tits into the attachment, and a mortise bit passes up the centre of the chisel into the chuck. With the motor running, work the machine as for normal drilling. As the bit removes the waste, the chisel simultaneously squares off the hole. A fence is usually provided to hold the work.
Cutting a mortise
Operate the machine as you would for normal drilling, moving the work along between cuts to complete the mortise.
Other attachments
The drill press can take a router attachment but many drill presses do not run fast enough for clean router work.
A drum sander has a shaft which fits in the chuck. Bolt a |in. thick plywood sheet to the table with a hole cut in the centre so the drum can be positioned below the surface.
A buffing wheel will also fit the chuck of the drill press.
Safety factors
Insure that the chuck key has been removed before switching on the machine. Disconnect the power supply before making any adjustments. Secure the work before drilling. Do not feed the drill too quickly. Where possible, fit a transparent chuck guard.
