How tight can I bend wood, and how do I model it?

Three ways to bend.

Draw a straight board, then bend it round a radius. Each method adds its own form and tools to the lists. Joints and most cuts still work on the bent board's straight runs.

Kerf bending

Saw kerfs across the inside of the bend, leaving a skin whole on the outside.

Steam bending

Solid hardwood up to 2″ thick, bent hot over a form. Softwoods are refused.

Bent lamination

Thin strips glued over a form; the strips are cut 1″ long and the list adds epoxy or plastic-resin glue.

How tight each wood will steam bend.

The smallest inside radius is a multiple of the thickness, from the wood's own bending behaviour.

White oak and ash

2 × the thickness.

Red oak, birch, cherry and walnut

3 × the thickness.

Hard maple

5 × the thickness.

Questions people ask.

Can I steam bend pine or fir?

Not in Mortise. Softwoods are refused for steam bending; use a kerf bend or a lamination instead.

Are the sizes of a bent part read before or after the bend?

After. Each straight run reads to the outside corner, and the bend shows its inside and outside radius, which you can edit.

The rest of Mortise.

• Cut listsThe parts to saw, the boards to buy, the hardware and the tools, read off the model.
• Real lumber sizesDimensional lumber, hardwood by the quarter, metric timber and sheet goods at their real sizes.
• Joinery and hardwareDovetails, mortise and tenon, dadoes and grooves, and every fastener and fitting as real hardware.
• Cut sheetsNumbered cutting diagrams and a cutting plan as a PDF that reads at print size.