DOWELS AND WOODEN THREADS

Making your own dowels provides for a great deal more flexibility in your woodworking projects than if you rely solely on commercial dowel stock. The principal advantage of cus­tom-made dowels is that you can use any species—one that matches the sur­rounding wood or one that contrasts. Another benefit is that you can size the dowels precisely to suit your needs. The simple shop-built jig shown on page 118 describes how to use a router to transform square stock into dowels.

Woodworkers have been cutting wood threads for more than 2,000 years. The Romans used wooden screws

in presses for olive oil and for wine. For the modern woodworker, wood threads have more pedestrian uses— in screws and bolts to embellish furni­ture or in shop-made clamps and vises. (See the front endpaper for instruc­tions on making wooden handscrews.) The traditional method for creating wood threads involved handcutting them using a triangular File. Nowadays, as shown on the following pages, you can do the job much more quickly and easily by cutting threads on dowel stock with your router. Be sure to use a fresh­ly sharpened bit; a dull cutter will strip the threads as it forms them.

ROUTING WOOD THREADS

2 Tapping a feed hole

To rout threads into round stock, you need to prepare a threading jig. As shown on page 117, the jig will guide the dowel stock into the router bit, allowing the cut­ters to carve the threads. Start with a wood tap the same diameter as the threads you want; a /г-inch tap is shown in the illustration at left. Secure your jig blank— a 2-by-3 board will do fine—face-up in a vise and use the tap to cut threads all the way through the stock (left). To feed the dowel stock into the jig, you need to enlarge the feed hole for about one-half its length. Install a bit in your drill press that is slightly larger than the feed hole, then position the hole under the bit, clamp the jig to the machine table, and adjust the drilling depth to one-half the stock thick­ness. Bore the hole (below).

3 Preparing the threading jig for the router

With the threaded jig on edge on the router table, as shown below, the tip of the bit you will use should just reach the bottom edge of the feed hole. Use your band saw to notch the jig for the bit, mak­ing two 60° angle cuts from the bottom edge of the stock that intersect at the center of the feed hole (right). The notch should be slightly larger than the bit. Mark the outside faces of the jig, then rip the board in half, separating the threaded por­tion of the feed hole from the unthreaded part; the cut is represented by the dotted lines in the illustration. Feed the cut face of each piece across a planer to flatten the surfaces, and make as many passes as necessary with the threaded portion until the crest of the first thread starts at the bottom of the V notch. This ensures that the jig will function properly.

Installing the jig on the router table

Install a 60° V bit in the router and mount the tool in a table. Clamp the threaded half of the jig bottom-edge down to the table so the tip of the bit is just in front of the thread (above). Adjust the router’s cutting height so the tip of the

bit is level with the crest of the thread in the jig. Butt the unthreaded half of the jig against the half already in place, align the holes, and clamp it in place. Make sure the marked faces of both pieces face out.

SHOP TIP

Making a handle to rotate dowels

To simplify the task of feeding dowel stock into a threading jig, fash­ion a turning handle. Cut a 2-by-2 piece of fine-grained hardwood about 10 inches long and drill a hole through it near each end. Make the holes the same diameter as the dowel stock you will be thread­ing. Into one of the holes, glue a 5-inch-length of dowel as a handhold. 5ore a third hole into an adjoining edge between the eecond hole and the end of the board this third hole will accommo­date a screw that secures the dowel to be threaded to the handle. Also cut a kerf from the end of the piece to the second hole to make it easier to tighten dowel stock in the handle. To use the handle, slip the dowel stock into the second hole and secure it by tightening a wing nut on the screw. The handle is shown in use on page 114.

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A DOWEL-MAKING JIG

Teamed up with an electric drill and a table-mounted router fitted with a 7^-inch straight bit, the jig shown at right can transform square stock into a dowel. The jig enables you to rotate the stock past a router bit that cuts away the waste. Cut the arm from a 2-by-3 piece of hardwood to a length of about 20 inches, then drill the bit clearance hole near one end through the face, making it slight­ly larger than the router bit diameter. Bore the feed holes in two steps. Start by drilling a hole through the edge of the arm that slightly overlaps the bit clearance hole; the diameter of the hole should equal the finished diameter of the dowel stock you want. Then switch to a larger drill bit and widen the infeed side of the hole enough to insert the square stock you will be using; stop drilling when you reach the bit clearance hole. Make sure the infeed hole is cen­tered over the outfeed hole. Finally, cut a dado across the bottom face

of the arm to accommodate the sup­port board.

To use the jig, set the arm on the router table, centering the bit clear­ance hole over the cutter. Slip the support board into the dado in the arm and clamp the board parallel to the table end. Whittle one end of the

square stock so you can tighten it securely in the chuck of an electric drill. Turn on the router and the drill, then feed the spinning stock into the infeed hole in the arm. As the router bit removes the waste, the dowel stock will emerge from the outfeed hole (below).