Mark 1-in. increments on both ends and one side of the hardboard. Then draw grid lines using a combination square, straightedge and fine-point permanent marker.
A second way is to use the transfer grid method . The shapes in Fig. A (attachmented at the bottom of this page) are drawn on a scaled-down grid. Draw a fullsize grid of 1-in. squares on hardboard and transfer the shapes to it; you’ll have a template you can use over and over. We’ve drawn only half of the backrest and seat struts on our grids because the halves are symmetrical. Make one template for half of the shape, then flip it to draw the other half. Since the shapes of the seat and backrest struts are so similar, you can make only the backrest strut template, then use it to draw the seat strut pieces, making them 1/4 in. narrower and 1 in. shorter (2 in. shorter overall).
Align the backrest strut template to the centerline and bottom edge of the cedar piece and trace the shape. Flip the template along the centerline to draw the other half. Cut out the pieces with a jigsaw.
To use the template, align it to centerlines drawn on the boards , trace around it, then flip it over the centerline and trace the rest of the shape. Remember, the seat struts are 1/4 in. skinnier and 2 in. shorter than the backrest struts.
Sand the edges of the curved pieces with a belt sander. If you don’t have a bench vise, you can support the legs with a handscrew clamp while you sand.
Cut all the pieces to the dimensions given in the Cutting List, using the templates for the legs and the top slat. Cut out the shapes with a jigsaw, then sand the pieces with a belt sander.
Drill the ends of the hand grip holes with a 1-in. dia. spade bit. Drill partway in from both sides so you won’t tear out the wood.
Lay out the hand grip hole in the top slat (C), then cut it out using a jigsaw and spade bit (Photo 6). You’ll need to rip the back and seat slats 2 in. wide using a table saw.
Lay out, countersink and drill all the screw holes for the slats and supports. Finish-sand all the pieces with 120-grit, then 150-grit sandpaper. Round over the sharp edges with the sandpaper.
Use a carpenter’s square to align the seat supports 90 degrees to the backrest struts, then glue and screw them in place. Use both glue and screws to attach the slats, too.
Screw the two seat supports (D) and curved top slat to the backrest struts (Photo 7) using the spacing given in Fig. A. Then attach the five slats to the backrest struts and six slats to the seat struts
Before applying the finish, unscrew the two seat supports and apply weather-resistant glue (like Titebond II or Gorilla Glue) to the joints, then rescrew the seat supports to the backrest struts. The glue will strengthen the joint. The chair relies primarily on these seat supports for strength.
Brush on two liberal coats of a penetrating exterior wood sealer (like Thompson’s Water Seal). Let the first coat dry for 24 hours, then apply the second coat. After an hour, wipe off any excess finish. Let the finish dry for a couple of days before using the chair. After a year or two, you’ll want to recoat the chairs to keep them looking good. If you decide to paint the chairs instead, use an oil-based primer followed by a semigloss oil-based paint. Don’t use a clear varnish; the sun will eventually break it down and you’ll be refinishing every summer instead of relaxing.
TIP: Cedar is soft, so when screwing the pieces together, finish driving the screws by hand to avoid setting their heads too deep.