Using a Drill: How to Drill Accurately

Always ensure that you are drilling at right angles to the work surface.

One way to do this is to line up your bit with an up-ended try-square and, if possible, enlist a helper to tell you when you are wandering off the vertical.

A surer alternative is to use one of the many types of jig now available.

Dowelling jigs, which give accurate siting and drilling of holes to take wooden dowels, range from the simple drilled metal block to more complicated (and accurate) calibrated types such as the Stanley Doweling Jig.

To position dowel holes when no jig is at hand, mark out their centres on one of the two members to be joined and drive pins into the marks. Nip the heads until only 5 mm (1/4 in) of shank is protruding, then position and press the other member down on to the first. Separate the members, remove the pins and then drill the dowel holes, using the pin marks as centres.

When using a power drill, make sure that the material to be drilled is firm and steady.

Large pieces usually present little difficulty and can be held firmly by hand, but always hold small pieces in a vice or cramp them to the drill table or bench. This will overcome the tendency of the cutting drill to suddenly snatch at the piece and spin it round.

The way to ensure 100 per cent accuracy for any drilling job is to use a purpose-made horizontal drill stand.

Ensure that you buy one into which your drill fits — which usually means it must be the same make, though the Arcoy stand will accommodate most makes.

With a stand you can widen your scope considerably. Mortise cutting is easy: you mark out the mortise and drill out most of the waste to a finely controlled depth, finishing the slot off with a chisel. You can buy a mortising attachment which does the whole job. Most drill stands are fitted with stops that can be adjusted for drilling to predetermined depths. Dowelling holes will also be true and square when done with a drill in a stand.

drilling accuratelyA simple attachment for use with a drill stand is the Stanley plug-cutter, which allows you to conceal screw or other holes in finished surfaces: cut a plug from a matching piece of timber, drive the screw well below the surface and glue in the plug, sanding it flush.

Other useful drill attachments are the Black and Decker right-angle speed changer, which doubles or halves the speed of the drill as well as allowing you to work round corners; and the flexible drive attachment for getting at really awkward places.

One word of warning about attachments: check that an attachment fits your drill before buying, as most makers’ accessories fit only their make of drill.

24. June 2011 by admin
Categories: Power Tools, Tools | Tags: , , | Comments Off on Using a Drill: How to Drill Accurately

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