tened to crosspieces. A rope is threaded through the crosspieces and serves two purposes: setting and holding the nose curve and providing a hand-hold for breathtaking downhill rides.
Since the runners also serve as this sled’s deck and seat, it is important to bend them precisely. They should have a radius of 314 to 4 inches, with the curl tightening slightly toward the end. For best results, use a wood with superior bending qualities such as maple or ash planed to % inch thick.
To finish a toboggan, seal the top surface with a coat of marine varnish. The bottom should be treated with hot pine tar, available from ski shops. T his will seal the wood and provide a surface to hold the runner wax. Work in the pine tar with a rag, using a propane torch on a very low heat setting to keep the tar fluid. To prepare the toboggan for a day on the hills, rub on a layer of hard crosscountry ski glide wax with a cork block.
The toboggan shown at left was made from steam-bent maple. Also known as a Canadian sled, this version is long and sturdy enough to carry two or three riders over the deepest snow.
|
2 Steaming the slats Build a steamer like the one shown at right from two lengths of Schedule 80 ABS pipe joined by an ABS T connector. Use push-on end caps to prevent the steamer from becoming over-pressurized. Glue a lA – mch connector pipe to the T connector and attach the connector to a commercial wallpaper steamer. To hold the wood above condensed water in the pipes, install a series of %-inch zinc-coated machine bolts just below the centerline of the pipes. Use both steel and rubber washers to make an airtight seal. Also drill a i^-inch drain hole at one end. Lastly, build a 2-by-4 frame that will support the steamer on a slight incline to allow condensed water to run out of the drain hole. To use the steamer, secure the push-on caps, turn on the device, and let the steamer warm up. Once steam begins to escape from the drain hole, place a slat inside. Close the end cap tightly and let the wood steam for about 30 minutes. To avoid scalding your hands, wear work gloves and use tongs when removing the wood from the steamer (inset). |
|
|
||
|
|||
|
|||
|
|||
|
|||
|
|||
|
3 Bending the slats
Cut a bending form from a board as thick as the width of the slats, following the profile of the toboggan. Screw the form to a base made from two %-inch plywood sheets and clamp the base to a work surface. Bore three 1-inch-diameter holes through the base for locking dowels around the curved part of the form. The space between the dowels and the edge of the form should equal the slat thickness. When you remove a slat from the steamer, place it on the form and use a wedge to secure the front end. Working quickly, bend the slat firmly and steadily, inserting dowels to secure the workpiece as you proceed (left). Use bar clamps to secure the slat to the straight edge of the form. Leave the slats on the form until they are cool to the touch—about 1 hour. The slats may spring back 1 or 2 inches, but the correct curve will be maintained with the rope.
|
4 |
Making the crosspieces
Make the crosspieces from 1-inch – thick, %-inch-wide stock and cut the pieces slightly shorter than the combined width of the slats. To cut the notches in the crosspieces for the tow rope, install a dado head in your table saw, adjusting its width and the cutting height to % inch. Screw a board as an extension to the miter gauge and position the rip fence to make the cut 1 inch from the end of the crosspiece. Holding the workpiece flush against the extension and the fence, cut a notch, then turn the board around and repeat to cut the notch near the other end (left). You will need one crosspiece at each end of the toboggan and at 11- to 13-inch intervals between.
|
5 |
Attaching the crosspieces to the slat
Arrange the slats on a work surface, align their ends, and butt their edges together. Spread glue on the underside of a crosspiece and clamp it across the slats about 2 inches from the back end; make sure the crosspiece is perpendicular to the edges of the slats. Glue another crosspiece in the middle of the bend at the front end. Install the remaining pieces at uniform intervals in between. Then turn the toboggan over and drill countersunk pilot holes through each slat at every crosspiece location; bore two holes through the outside slats and one hole through the others. Mark the drilling depth on the drill bit to avoid boring through the crosspieces. Then drive a screw into each hole (right).
6 Preparing the crown piece
Make the crown piece that will cover the front ends of the slats from the same stock you used for the crosspieces, but cut it about twice as wide and slightly longer. With the same dado head adjustment you used in step 4, raise the cutting height to Ул inch. Center an edge of the workpiece over the dado head and butt the rip fence against the stock. Also clamp a braced featherboard to the table in line with the blades. Then use a push stick to feed the piece into the dado head, cutting a groove along the bottom edge (right). Fit the piece over the ends of the slats, then drill pilot holes through it at each slat location. Secure the piece in place with stainless steel screws. Also bore a hole through the crown piece near each end for the tow rope. Use a belt sander to smooth the edges of the outside slats flush with the ends of the crown piece, and bevel the edges of the cross pieces with a sanding block, eliminating any sharp edges.
|
7 |
Finishing the toboggan
Finish the top surface of the toboggan with a coat of marine varnish and the bottom with pine tar (page 58). The final touch is installing the tow rope. With the toboggan flat on a work surface, use a pair of clamps to hold the nose at the desired bend. Then knot one end of the rope and thread it through one hole in the crown piece and through the notches in all the crosspieces. Feed the rope across the back-end crosspiece, then back up through the remaining notches and knot at the front (left). After releasing the clamps, make sure the pressure is equal on both sides of the toboggan. Adjust the knots, if necessary. The toboggan nose should have a fair amount of spring without overstressing the wood.
|
|
