What is a breadboard end and how is it fitted?

The purpose is twofold. A long cross-grain strip is very stiff and resists the panel cupping, and it covers the end grain of the panel with a clean long-grain edge that takes finish evenly and does not chip. The complication is that the panel changes width and the breadboard end does not change length, so the joint has to be a sliding one — and the moment somebody glues it all the way along, the panel splits.

Step by step

1. Understand the movement problem before cutting anything.The panel's width will grow and shrink by several millimetres over a year. The breadboard's length will not change measurably. The joint therefore has to be free to slide everywhere except at one point.
2. Flatten and true the panel first.The breadboard end will hold whatever shape the panel is in when it is fitted. Flatten it, and shoot the end square.
3. Cut a long continuous tenon or tongue on the panel end.Traditionally a tenon with shoulders and haunches; simpler versions use a full-length tongue cut with a router. Either way it wants to be a good sliding fit in a matching groove.
4. Cut a matching mortise or groove in the breadboard strip.Test the fit dry along the whole length. The breadboard should sit down onto the shoulders with no gaps and slide off again by hand.
5. Drill the peg holes through both parts together at the centre.The centre peg is the anchor and its hole stays round in both parts.
6. Elongate the outer peg holes in the tenon only.Drill through both, then take the breadboard off and file or drill the holes in the panel's tenon into slots running across the panel's width. The holes in the breadboard itself stay round.
7. Glue only the central portion.Glue across roughly the middle third at most, and often only around the centre peg. Everything outward of that is dry, so it can slide.
8. Peg it and leave the pegs slightly proud, or trim flush.Draw-boring the pegs — offsetting the hole in the tenon a fraction towards the shoulder — pulls the joint tight without clamps, which is the traditional method.
9. Expect the ends to be flush at one time of year and not at another.In a dry winter the panel narrows and the breadboard ends stand slightly proud at the corners; in a damp summer the panel is wider. That is the joint working correctly, not a fault.

Tips

• If you want the look without the joinery, a mitred and glued edging on a plywood top achieves a similar appearance with no movement problem at all, because plywood does not move.
• Make the breadboard end from the same board as the panel if you can, so the colour matches at the joint.
• This is an advanced joint and the panel is usually the most expensive part of a project. Practise the tongue-and-groove version on an offcut before committing.

Common mistakes

• Gluing the breadboard end along its full length — The panel cannot then change width and it splits, usually straight down the middle within a year. This is the defining error of the joint.
• Drilling all the peg holes round — Round holes at the outer ends pin the panel just as firmly as glue does. The outer holes in the tenon must be slots.
• Fitting a breadboard end to a panel that is not flat — The stiff cross-piece locks in whatever twist or cup is present, permanently.

Questions people ask