Rule Joint

This topic contains 8 replies, has 6 voices, and was last updated by  David Perrott 8 months ago.

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    Glenn Dube

    I have to make at top for a drop leaf table. Does paul have an example of making a rule joint anywhere on his sites?



    I’m not sure that he does.
    Although it may not appear so, this is probably one of the most difficult mating joints to do well for its full length – the width of a table top -where it does not bind as the hinges move and is fully crumb-proof and without gaps. Many current makers chicken out of hand made rule joints on a drop-leaf because it can take time and effort to get right.

    There are three basic ways to make a table-top rule-joint in this day and age:

    By hand: The way that it was always done….Construct a pair of male/female interlocking quadrants on two identical mating board edges with a pair of hollow and rounds of the correct size for your board thickness. You need to begin with making an accurately interlocking template of both halves so that it can be checked for fit inch by inch as you go.

    With matching planes: As a continuation of the method above. In a previous age, plane-makers produced pairs of exactly matching table-joint planes that would refine an exact rule joint formed by the previous method. These were finishing planes – not usually intended to do the whole joint from scratch, though many attempted it. There’s a description of Table Planes and a sketch in R A Salman’s Dictionary of Woodworking Tools, Page 367. If you find a complete working pair of these, consider yourself lucky. They are extremely rare, having been split up, damaged… lost when the older craftsmen died.
    However, I believe that some of the quadrant/profile cutters in the Stanley 55 could be used or adapted for this purpose, but I’ve never used one. Anyone know more on this?

    Which brings us to the third…
    By machine: matching pairs of cutters are available for electric router users. Noisy, dusty, but produces an accurate joint quickly and is what is generally used nowadays.

    Sorry.. not an easy answer to this one.


    Glenn Dube

    I thought it might not be easy. The router tools for this joint don’t necessarily work as I think the dimensions of the joint rely on the hinges used as they make the radius the joint has to follow. I actually forgot about the match planes used for this and your right, I doubt I’d find a set that would work the way I want. Paul has plane making instructions that really interest me so maybe I’ll delay the table top project until I have made a couple of practice planes, then make a set of planes to match suitable hinges and do it then.

    Paul recommended as a reply to me that the stanley55 seemed like a great idea but was not too good in practice.



    This note by Matthew Bickford may show the rudiments of making a rule joint with a pair of hollow and rounds:

    In this case he uses a pair of number 8s, yielding a 1/2 inch radius on the joint. (No: 8 is 8 x sixteenths, or a half inch radius). Though you can use any size to suit the thickness of your board. Where a purpose made-pair of exactly matching Table Planes consist of a quadrant of 90 degrees, H&R planes only have a segment of 60 degrees but it is possible to do it.
    Finally, it is crucial to get the correct style of hinges for thhis type of table….and set them out, recessed, so that the centre of the pin and knuckle sits of the exact centre of your radius.

    Davis Charlesworth has also made a video exploring rule joints by hand, but it’s expensive.

    Good luck


    Glenn Dube

    Thanks for this but I’m having a bit of a hard time “seeing” what I’m looking at in his diagrams. The idea of making a set of hollow and rounds for this is appealing but I’m not sure I understand ho his instruction diagrams work. Are the colours different planes or the cuts they make?


    Jim Thornton

    Here’s a link to the MLCS website where Rule Joints are talked about:
    They’re naturally referring to using matching cove and round over router bits to form the joint. I’m not too knowledgeable about moulding planes, so am wondering if round over and cove moulding planes are available? For a one off, router bits may be the way to go.

    Here’s a link to Paul’s blog where he talks about cove cutting planes:

    Wouldn’t it be nice if we could just reach up on the shelf and grab the moulding plane we need?


    If you can't afford to do big small things in a big way!



    I’m having a bit of a hard time “seeing” what I’m looking at in his diagrams

    You’ll need to double check, but he uses a technique in which he establishes rabbets and arrises to guide the rounds and hollows. Look at the six diagrams at the top of that page, the ones in light purple.

    The three on the left show how the concave round is made. In the top left, a shallow, wide rabbet is cut (red). In the middle left, a square rabbet is added.This produces two arrises and a rabbet to guide a round which then removes the material in red in the middle, left diagram. The end result is the bottom left.

    The three on the right show how the convex round is made. In the top right diagram, a shallow, wide rabbet is cut. In the middle right, a chamfer has been taken off. The red material in the middle right is what will be removed by the hollow, which is guided by the arrises of the chamfer. I suspect the bottom right was just supposed to be the purple part, (no red) and shows the final convex part of the joint.

    I think that’s what is being shown. Hope that helps. His book might help.

    • This reply was modified 8 months ago by  Ed.
    • This reply was modified 8 months ago by  Ed.
    • This reply was modified 8 months ago by  Ed.

    Dan Williams

    For one table I would create a pair of profile scrapers. Rough out with your method of choice and finish with the scrapers.


    David Perrott

    There is a Roy Underhill program called Table Joints Rule where he discusses it. Bill Anderson his guest wrote an article in Popular Woodworking on how to do it. Yes its complicated. There are many important aspects to be aware of including the hinges. In Joshua Kleins video about table making he does a drop leaf table with out the rule joint.

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