Guides

Sketching woodworking plans on iPad

Most furniture starts as a sketch with sizes scribbled on it. On iPad that sketch sits on proper isometric paper, keeps a page for every part, and doesn’t end up under a pile of offcuts.

Start with the overall sizes

Before any joinery, fix the three numbers that matter most: width, depth and height. They usually come from the space the piece goes in, or from what it has to hold. Sketch the piece as a plain box on isometric paper and dimension those three first. Every part size is worked out from them.

Break it into parts

Draw the piece in isometric, then give each part a letter: sides A, top B, shelves C. Each part then gets its own page with its finished length, width and thickness. A page per part keeps each drawing small enough to read at the bench.

Draw to your real stock thickness, not the name on the rack. Plywood sold as ¾ inch is often closer to 23⁄32, and a shelf sized for the nominal thickness won’t sit right in its dado. Measure a board and use that number.

Mark the grain direction on each part with an arrow. It decides how the part is laid out on the board, and which way it will move with the seasons.

Detail the joints on their own pages

Joints are where plans go wrong, so draw them larger and by themselves: a dado, a rabbet, a mortise and tenon, a half-lap. Dimension the width and depth of every cut, and say which face or edge each measurement is taken from. That reference face is the one you’ll put against the fence.

Make a cut list before you cut

List every part with its letter, how many, and its finished size. Then sketch a cutting diagram: the parts as rectangles on a sheet of plywood or along a board. Flat views like this are easiest on square grid paper at one square per inch, or two for a full sheet. Leave room for the saw kerf between parts, and put the parts whose grain direction matters on the sheet first.

Sketch first, then model if you want to

If you use SketchUp, Fusion or Shapr3D, the sketch still comes first. It settles proportions and joinery quickly, so the model goes quickly too. For plenty of shop projects the dimensioned sketch is the whole plan.