Replies

1. 
   rococojo | Aug 05, 2009 02:19am | #1

   Alan, when setting out your hinges, move the hinge knucle pockets to the rule edge by a cock-hair, this will stop any binding when assembled.

2. 
   BG | Aug 06, 2009 01:35pm | #2

   alan,
   Practice, practice on large pieces before touching your project. As I'm sure your aware, the objective is to have a perfect joint and not have the hardware show when the leaf is in the down position. Generally speaking when the quirk aligns with the center of the barrel of the hinge your good. However, once you drive those screws...and if there off just a tad...oiy! Be sure your practice scraps are the same thickness as your project....

3. 
   joinerswork | Aug 06, 2009 04:21pm | #3

   alan,

   rococcojo and BG have given good advice.  Within reason,  moving the knuckle closer to the edge of the top will 1) move the dropped leaf away from the table top, reducing the chance of rubbing or binding as it is lowered. and2) move the edge of the leaf up towards the top surface of the top when is is its lowered position, which helps to hide the inletting for the hinge at the table's edge.  Now, a too-wide gap (as you look down) will counteract the raising of the leaf edge (as seen looking across the top), so their is a sort of ying-yang thing that happens as you move the hinge knuckle outboard. 

   Keeping the knuckle of the hinge in alignment with the center of the rule joint's radius is ideal, but runs the risk of rubbing or binding if the wood of the top or leaf moves just a little.  Further, as the hinge is moved inboard, it gets closer and closer to revealing the rule joint's bottom edge, when the leaf is dropped.

   If the hinge ends up just a little behind the center of the rule joint, then the leaf will definately bind as it is lowered.

   I like to cut the rule joint so that the half on the table top is just a tad more than a quarter circle (when viewed from the end of the top) its radius up 1/16" or slightly less (about the thickness of the hinge material) above the bottom surface of the top. This 1/16 or so can be rounded back or nosed under, continuing the arc of the rule joint.

   The corresponding half of the joint that is worked on the leaf I like to cut a bit deeper than what would be "ideal".  So that there is a gap of 1/32" or slightly more between the two halves of the joint when they are put together.  This is the fudge factor, allowance for error in hinge placement, wood movement, spilled oatmeal, or other bad things that might happen to the joint.

   On old work, you often see that the leaf's coved edge matches the rounding under of the top's more-than-quarter-round edge.  This profile is not practical (or necessary) when cutting the joint with modern power tools, router or shaper.  Just cut the quarter round "deeper" than a quarter circle.

   One shop I worked in used to inlet only the barrel of the hinge knuckle, surface mounting the hinge leaves without inletting them.  This, the boss said, was to keep the underside edge of the top "clean" so that it showed a straight edge when the leaf was dropped.  Of course, it is not traditional to do so, and any swinging  leaf support will be fouled by the hinge if it has to pass across it, so must be notched to clear.  Their rule joint as I recall, was more of an ovolo than a quarter-round, so the reveal of the joint (and the placement of the hinge beneath) was engineered to put the edge of the leaf slightly below the edge of the top when the leaf was dropped.

   In hanging the leaf, I like to clamp the top and leaf together, with a layer or two of sandpaper between them (sandwiched in the joint) to hold them just an ooch apart as the screws are driven in. 

   There is the possiblity of variations in the geometry of your cutters, so that mocking up a joint in scrap is a real good idea, plus you can keep the pair of scraps that works for you to set up future cuttings.

   Ray

1. 
   RW | Aug 06, 2009 11:38pm | #6

   Best synopsis I ever ran across anyway . . .

   http://www.whitechapel-ltd.com/tech/drop_leaf_table_hinge.shtml

    Real trucks dont have sparkplugs

2. 
   zolton | Aug 07, 2009 03:44pm | #7

   Ray,

   I wasn't even interested in this thread until I came across your description of how to mount the hinge in a rule joint. As well said as anything I've ever come across on this site. Nicely done..

   ZoltonIf you see a possum running around in here, kill it. It's not a pet. - Jackie Moon

1. 
   joinerswork | Aug 07, 2009 04:20pm | #8

   Zolton,

   Glad you found it helpful.

   Ray

4. 
   forestgirl | Aug 06, 2009 07:18pm | #4

   Alan, there are a number of articles on the internet showing how to mill the joint and install the hinges.  I've linked three below.  Did you buy hinges specifically designed for a rule joint? -- one hinge leaf is shorter than the other.  I've made 3 projects with rule joints, and it is a challenge.  The recommendation to practice and get the joint perfected is dead-on.

   If  you are a subscribing member of the FWW web site, there are two articles that will help.

   • Basic rule joint article  (FWW)
   • hand-tool oriented article with excellent drawings of various incorrect hinge locations and how to correct them (FWW)
   • MLCS article

   Lots more illustrated articles available on the web, I'm sure.  It's a process that seems to demand visual aids. :0|

   forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-) 

   
   

   ---

   Edited 8/6/2009 12:19 pm by forestgirl

5. 
   BG | Aug 06, 2009 07:29pm | #5

   Alan,

   Can you imagine discovering all those tips on rule joints that Ray spelled out on your own...wow!

6. 
   RMillard | Aug 07, 2009 09:24pm | #9

   I posted this the other day, to a similar question

   47573.7

   Rob Millard