Woodworking Techniques – Grooving, Joining, Drilling, Clamping

Grooving and Joining

Mortises and mortised hinges require that you clean and straighten surfaces that haven’t been fully cut with a saw or drill. This is the chisel’s job, and it will go easily as long as the tool has a consistently sharp edge.

On most work, you won’t need to use a mallet; hold the chisel in your right hand to provide the push, and guide the blade with the left to control direction. If you do use a mallet, strike the tool lightly so as to avoid taking big bites at once. Work with the grain and hold the tool at a slight right or left angle whenever possible, because this makes the smoothest cut and is less likely to dull the blade. To avoid gouging the work, don’t drive the edge too steeply — hold the blade at a slight downward angle.

For deeper cuts or shaping work, a router can handle quickly and cleanly what would take some time with a saw and chisel. The shape of the router bit’s cutting surfaces determine what the finished edge or groove will look like. A straight bit makes a slot the width of the bit itself; a roundover bit cuts a clean, rounded edge into a squared surface; a chamfer bit cuts a bevelled edge; and a an ogee cuts a detailed profile.

When operating a router, you should grasp it comfortably in both hands and position yourself to get a clear look at the working bit — be sure to wear eye protection. The rule is to move it from left to right; if circular or irregular cutting is needed, then the motion should be counter-clockwise. It is best to make any cuts across the end grain of your work first, then with the grain to avoid chipping.

The base of the router is loosened and the motor housing adjusted up or down to control the depth of cut. Before making any permanent cuts, you should run a test on a piece of scrap wood to see what your work will look like. Practice will improve your control of the tool, and after a while, you’ll begin to rely on the depth gauge marked on the side of the router rather than having to test every cut you make.

Freehand work is fine for short jobs, or when the bit has an attached pilot bearing, but when making long cuts, you’ll probably need to clamp the wood to a bench and use the tool’s base–mounted guide to keep the cut straight. If you don’t have a guide, you can usually substitute by clamping a straight section of 1 x 2 to the bench or your work, parallel to the line you wish to cut.

To rout narrow stock or edge–rabbet grooves, you’ll need to place a piece of scrap stock to the right and left of the work, flush with the working surface. This will prevent the router base from tilting to one side and spoiling the cut, and will give you a place to mount a guide if you use one.


Drilling and Countersinking

woodworking techniques - countersinking There are three parts to a screw hole: the pilot or lead hole (which is a little more than half the diameter of the screw itself), the shank or body hole (the same diameter as the screw), and the sink or bore, used if the screw head is to be recessed below the surface of the wood.

In softwoods, it’s not really necessary to drill more than just the pilot hole for a short screw. Dense hardwoods and long screws sometimes call for a shank hole, too. Make that hole only as deep as the shank — the unthreaded portion of the screw — is long. Also, remember that screws driven into wood’s end–grain have less than half the holding power of a screw driven perpendicular to the grain.

Combination countersink and pilot bits, called screw bits, simplify hole–drilling considerably. They’re sized by screw numbers, and their stop collars and countersinks are adjustable for length. They use specially tapered bits that accommodate standard wood screws perfectly.

Cabinet screws are even easier to use in some situations, as when driving into softwoods using 1-1/2″ or shorter No. 6 and No. 8 diameters. These are self–tapping power–driven screws that don’t need pilot holes, though you should take care to pre-drill the pilots when working near the end of the wood.

Another variation known as deck screws are coated with a smooth anodization which makes them weather–resistant. They’ll work in softwoods and hardwoods, but the screw holes should be predrilled for harder wood or you may split the wood or shear the screw head off.

Drilling socket holes can be done with a regular drill bit if the diameters are small enough – 1/4″ or 3/8″. A hole larger than that needs a Forstner bit, which produces a clean, flat–bottomed hole. A stop collar or a piece of tape can be used on a standard drill bit if you feel you may have trouble gauging the depth of a socket correctly.

Drilling through–holes takes some care in not tearing out the back side of the work, especially if another piece is planned to face it. You can avoid splintering wood this way by drilling only partially through the piece, then coming at the hole from the opposite side. Using a small pilot bit to penetrate the back face helps to locate the point at which to start the second hole.


Clamping

Most of the clamps used in woodworking function to hold parts together while they’re being glued. They can also secure pieces for cutting or drilling.

Bar or pipe clamps are especially suited for wide clamping jobs because they’re long and relatively inexpensive for their size. A sliding tailpiece permits a large range of adjustment between the jaws.

In the case of joints or pieces less than 12″ in depth, a C–clamp is the logical choice. These clamps come in standard and deep throat depths, but they all have a threaded rod with a swivel tip that applies pressure to the work as you tighten the rod. You should cut some 2” square pads from scrap pieces of 1/4″ plywood to keep the metal tips from marring the face of your work.

The best results in joint–clamping come when you place the clamp’s pressure points directly at the centerline of the work or joint to be glued. Snug-tightening is best, since over-tightening can damage the wood and, with gluing, force enough adhesive from the joint to cause uneven distribution and a weakened bond.

06. December 2010 by admin
Categories: Home Maintenance, Woodworking | Tags: , , , , | Comments Off on Woodworking Techniques – Grooving, Joining, Drilling, Clamping

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