Workshop Wednesdays - Rule Joints archive
Wednesday 8 April 2015
Mark Ripley shows us his failsafe cutting method for this most difficult of joints
A rule joint needs some specialised equipment and fittings comprising a matched pair of router cutters, one rounding-over bit and one coving bit. I prefer bearing-guided cutters for ease of setting up.
Specialist table hinges are also needed and I go for Isaac Lord's item No.30140, which is the bigger and stronger of the two they offer - see www.isaaclord.co.uk for more information.
The wood should be close to quartersawn for stability; I am not, and this is a view shared by many of my clients, keen on pure quartersawn oak (Quercus spp.) because of the medullary rays, so just off quarter works well.
Rule joints are highly visible so design is an important issue. A radius of about two-thirds of the thickness of the tabletop is about right and 16mm-radius cutters are good for table thicknesses of 22-25mm. I'm not sure that a rule joint would work visually in a thicker top and it is unlikely that you would want a dining tabletop of less than 22mm.