Here's How

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  Step 1: Start with 680mm-wide door and use its features to decide shape of lounge sides. Here, it had 5 panels, with top of door to underside of first rail measuring 460mm, top rail 100mm wide and intermediate rails 90mm. Draw a line across door along underside of first rail, then measure 70mm further down at front edge. Join to where line crosses back edge of door. This gives a backward slope of about 1:10. Adjust measurements to suit your door.
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  Step 2: Use a power saw to cut door, but raise it on gluts so you don’t cut through your bench. As you don’t know what’s in the old paint, make sure you wear protective glasses and mask. To match size of intermediate rails, cut 10mm off top to give a front edge height of 520mm. Use saw fence to cut off strip.
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  Step 3: Square door along top of next rail and cut with power saw. To do this, measure from far side of saw blade to edge of
  saw base (here 33mm) and clamp straightedge to door. Cut along straightedge.
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  Step 4: Use first panel to mark out second side. If sides of door are different, turn first panel over so you have a mirror pair.
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  Step 5: Cut second side following lines you drew. Use a jigsaw to remove small wedge of panelling remaining, leaving beading in place for a more refined look.
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  Step 6: Cut backrest out of 600mm-wide door. Let panel layout determine length. We removed bottom panel with its wider rail to create a 2.5-seater, with seat length of 1550mm. Remember, each person needs about 600mm of bum space. Cut third door to same length, then rip to about 500mm wide for a comfortable seat depth. However, to make this cut, set saw to cut about 3° off square, to bevel the cut. This will give backrest a slight slope.
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  Step 7: Mark a line 20mm up from bottom of backrest, and mark 7 equally spaced holes along it. Predrill clearance holes for 100mm screws, then counter bore with a 12mm bit for inserting dowels to hide screw heads. To make sure the bit doesn’t bite too deep, measure exposed length of drill bit from tip to chuck, then cut a wooden block 10-15mm less in length. Bore a 12mm hole down centre. Slip over bit. This block stops you boring too deep. If you don’t use the stopper, the 12mm bit is likely to pull all the way through timber before you can stop it. Counter bore all holes.
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  Step 8: Apply glue to bevelled edge of seat, place on bench so backrest will lean back, then screw backrest in place.
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  Step 9: Place 1 side on bench and locate seat assembly on it. To align seat with side, locate front top of seat 300mm from bottom and 80mm in from front. The underside at back of seat is 165mm up from bottom.
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  Step 10: Cut a 60mm-wide rail from remaining stile of third door, to support front of seat. It also creates a few extra screw positions for screwing seat in place at front. It should already be the right length. Stand this in place under seat but set it back 5mm to form a shadow line. Clamp in place. Mark around seat and rail, as well as back.
• Step 11: Remove seat assembly and drill clearance holes through sides using marks as a guide. You’ll need 4 holes down the back, 1 into front of seat and 2 into ends of rails. Turn over and use 12mm bit with spacer block to counter bore for screw heads and dowels on outside of side.
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  Step 12: Stand seat assembly on ground, apply glue, align side on seat assembly using marks you made, then screw on with 100mm screws. Repeat Steps 9-12 for other side, using same measurements.
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  Step 13: Cut handrails from remaining rails of side door. They are 80mm wide and 40mm thick. Glue and screw to tops of sides.
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  Step 14: Cut 15mm lengths of 12mm dowel, apply glue into holes, then hammer until they’re firmly held. Don’t force them in too far, as the compression will try to push them out again. When glue is dry, use a fine-toothed saw, such as a plywood saw, to trim dowels flush with sides or back.
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  Step 15: Sand entire unit to reveal original timber, undercoats and succession of top coats. You’ll be cutting back through time as you reveal successive layers and will never quite know what you’ll find or whether you’ll run into older, more toxic paints, so wear safety glasses and mask. Use a belt sander if you have one, cutting back as much or as little as you want. Concentrate on edges or sand in middle of panels. Once you’ve exposed old finishes as desired, switch to a less aggressive palm sander with finer paper to smooth surfaces. It’ll do a better job of exposing broader areas of old colour, which may only be a few microns thick.
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  Step 16: Paint on 2 coats of clear acrylic to protect raw timber and sanded areas of undercoat, and cover old coatings that may have traces of lead.
• Step 17: To make the lounge really comfy, have a 100mm thick foam cushion cut to seat size and stitch up covers. Use cushions as a backrest so you don’t completely cover up door panels.