Lap Joints

Used for corners in cabinet and box construction the lap, or rebate, joint is one of the easiest to make with hand tools. It consists of a rebate cut in one component, into which the plain end of a second component is glued. The lap refers to the wood that remains from the rebate, which conceals the end grain of the second piece. Not the strongest of joints, the lap is usually reinforced with panel pins.

Tools you need

  • 2H pencil
  • Steel rule
  • Tenon saw
  • Marking knife
  • Marking gauge
  • Shoulder plane
  • Chisel
  • Try square
  • Shooting board
  • Glue
  • Brush
  • Cramps
  • Pin hammer
  • Pins
  • Nail punch

How To Make A Lap Joint

1.  Cupieoes pieces of timber to length, making the rebated piece (A) 2 mm (1/16 in) longer than its finished size. Mark the shoulder line in from one end of piece A, allowing for the extra 2 mm (16 insoribe scribe with the knife. Continue the lines over both edges.

2. Set the marking gauge to one-third the thickness of piece A. Working from the face side, scribe a line across the end grain and continue around both edges to reach the shoulder line. Pencil in the waste to be removed to form the rebate.

3. Place piece A in the vice and tighten. Saw along the lap line until you reach the shoulder, taking oare to cut on the waste side. Remove from the vioe and either cramp pieoe A to the bench top or hold it against a bench hook. Saw across the shoulder line until the waste part is loose.

4. Clean up the rebate with a shoulder plane or pare carefully with a chisel. Check frequently that the corner of the rebate stays square, as it is easy to tilt the plane over when used on its side. Trim the end grain of part B on a shooting board or in the vice and check that both components fit together neatly.

5.  Glue the joint together and apply cramps, with offcuts to prevent damage. Cheok with the try square held on the inside that faces are at exactly 90 degrees to each other. If reinforcing with pins, nail these in dovetail formation – that is driving the nails at alternate angles – through the lap and punch below the surface. It is easier to hold the joint in the vice for this operation.

6. When the glue has dried, hold the joint in the vice and trim the excess from the lap with a smoothing plane. Work in from both sides towards the middle to prevent the timber breaking out.

Alternative Method

An accurate rebate is quick to make with the portable router, although you will get better results if you cut two or three components in one pass. Line boards up and hold them together with a sash cramp and temporarily pin (or cramp) a straight batten across them at 90 degrees. The batten acts as a guide for the base of the router, which should be fitted with a straight cutter. If the ends of the timber are sawn accurately you can use the side fence to guide the router. Alternatively, rebates can be cut safely on a router table with the machine mounted upside down.


Word Discription :

Face side When preparing timber this is always the first face to be planed. It mperfeotlyrfectly flat and straight.

Rebate A step formed along the edge of a piece of timber, usually rectangular in section, to accept a panel of solid wood or sheet material. Also known as a rabbet.

Shooting board A jig for planing edges or end grain of timber accurately. It consists of two boards glued together, the upper one narrower than the other. The side of the plane runs on the lower board, trimming the work piece that sits on the upper level.

Shoulder The squared end on either one or both sides of a tenon or tongue.

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