Replies

1. 
   RMillard | Apr 18, 2004 04:05am | #1

   I see no need for matched bit sets for rule joints. I make my rule joints on a shaper or with molding planes. I have never heard of not mortising the whole hinge in flush, and not doing so would in most cases require the top of the aprons to be notched for the hinge. I’m having difficulty visualizing this, but not mortising the hinges may make them show when the leaves are down. Of course the actual reason to mortise common hinges is to allow them to carry weight (vertically), something rule joint hinges don’t have to do.

   I’ve made several pieces with rule joints, and they can be finicky to get right. I usually make a sample board to test the fits and use it to set up the actual joint. The difficulty in setting it up, is that in the finished joint, it should not bind and the hinges nor their mortises should not show when the leaves are down. Also, at the ends there should be a nice even fit of the two profiles of the joint when the leaves are up. I cheat by fitting the joint tight, and the relieve the hollow part with a molding plane or gouge every where along the joint except at the ends, but not removing any at the lip, so there is a bearing point when the leaf is up, and an even gap when down. Another thing I do is leave the leaves about 1/32” thicker than the top, to allow me to hand plane them down perfectly flush with the top, after they are fitted. Doing this requires you to index off the bottom face when machining the joint. There is an excellent overview of rule joints in the following books, David Charlesworth’s Furniture-making Techniques Volume Two , Encyclopedia of Furnituremaking by Ernest Joyce, and Woodwork Joints by Charles Hayward. I‘m sure there are others but these are the ones I‘m aware of off the top of my head..

   Rob Millard

1. 
   BG | Apr 18, 2004 01:55pm | #4

   Rob,

   Based on your comments I did curl up with E. Joyce's last night to see what he'd give up....need to do more reading, maybe I'll take a look at Charlesworth too.

   The more I begin to understand the complexity of the 'rule joint' the more I wish I had hand molding planes...so I could sneak up on a good fit especially on the ends.

   I think I'm beginning to see how surface mounting the hinge and morticing the barrel only makes some geometric sense....in that, the center if the barrel hinge is also the dead center of the radius....and morticing the entire hinge moves the center to the radius closer to the cove/roundover than it should be relative to the bit profile.

   Okay, lots of scraps and off to the basement to play. thanks   

1. 
   ian | Apr 18, 2004 02:12pm | #5

   BG

   I should have addressed #17380.4 to you rather than all

2. 
   joinerswork | Apr 18, 2004 05:41am | #2

   BG,

   Whatever size bits I use, I work the quarter round on the top first.  I aim to have the mold come out flush with the underside of thetop.  In other words, if a compass were used to lay out the quarter round on the end of the top, the center point is exactly on the bottom edge of the tabletop.  Then I cut the cove on the underside of the leaf.  I'll aim to have this cut just a bit deeper than what would be a perfect match.  When I put the two pieces together, the fillet on the edge of the top and the flat on the edge of the leaf meet, but there is a slight (about 1/32") gap between the cove and quarter round.

   All the old dropleaf tables I've seen have had the hinges mortised in.  One shop I worked in just inset the barrel of the hinge, and the leaves were surface mounted.  I asked why, and the answer was that they didn't want the edge of the mortise to show when the leaf was down and break up the line of the underside of the top.

   The key to successfully hanging a drop leaf is to understand the relationship between where the hinge is mounted  when the leaf is up and what that does to the positioning of the leaf when the leaf is dropped.  

   If your cove and quarter round are,  for instance, 3/8" radius, scribe a line 3/8" back from the edge of the top, on the underside.  (That is the center of the radius  of the quarter-round that you worked on the edge of the table top).  If you inlet the hinge such that the center of the hinge pin is on that line,the cove on the leaf will maintain the same gap as it is dropped.  However, this means that the edge of the leaf, when down, will be exactly even with the underside of the top, revealing the mortise for the hinge.

     Moving the hinge pin slightly nearer the edge of the top will have the effect of (1)raising the leaf's edge in the dropped position (if you're looking at it from the side), while (2) moving it away from the edge of the top (if you look down from above).  This has the benefit of(1) hiding the edge of the hinge mortise, and (2) helping keep the leaf from rubbing as it is lowered/allowing for a little warpage in the future.  This is what I aim to do when I hang a drop leaf.  Just be aware that going too far in this direction can leave an unsightly gap between top and leaf (from above, with leaf down), and can put the barrel of the hinge dangerously close to the "show side" of the quarter round.

   Conversely, if you were to inlet the hinge with its pin further away from the edge of the top, the leaf will hang further down the hinge when dropped, exposing more of the under edge  of the top  (viewed from the side), and could even pop back under the edge of the top (viewed from above) when it is dropped. 

   I like to clamp the top and leaf together when I  scribe the leaf for its hinge mortises.  I was taught to put a piece of card stock, (or doubled up sandpaper) in the joint, near each hinge, and also when driving the hinge screws, as insurance against binding when the leaf is worked.

   First time out, till you are familiar with your cutters' geometry, it will be a good idea to make a trial run with scraps.

   Cheers,

   Ray

1. 
   BG | Apr 18, 2004 02:23pm | #6

   Joinerswork,

   Your explanation is excellent.  I think a clear picture is starting to emerge of the complexities.  The first thing I'm going to do is get some extra screws for the hinge...I suspect I'll need that for all the trial and errors. 

   I have 3/4 finished stock and will probably use 1/2 cove and roundover bits.  The hinge is probably 1/16 to 3/32" thick (maybe an 1/8") which if I mortice in the whole hinge, will mean the hinge radius will be different (longer relative to the router bit cuts, or actually, different reference point ) than the router bit radius(because that was made using the underside of the board as the reference).  What I hear you saying is I have to giggle that relationship with where the screws attach to the stock..?

   This is gonna be fun... 

1. 
   joinerswork | Apr 19, 2004 04:53am | #11

   BG,

   If you're going to sit around and giggle, you'll never get anything done.  Get up and get to work, this is no laughing matter!  Just kidding. 

   If you wanted to, you could work the quarter round so that it's more than a 1/4 circle, by putting the radius point somewhere above the bottom of the table top.  Then you will probably want to "round under" the molding a bit.  If you are using router or shaper bits, it will be harder to get the cove undercut  to match this profile. I've seen plenty of hand planed rule joints done this way, however. More trouble than it's worth, in my opinion, because moving the pivot point of the hinge above the same place on the top helps to hide the mortise (when the leaf is down).  Also, with most dropleaf hinges, if the hinge leaves are inlet flush, there is still a slight bump standing proud at the barrel.  That means the center of the hinge pin is not as deeply inletted as you might think.  Try it on a pair of scrap strips, and see.  Just use one screw on each side of the hinge till you know where you want to end up.

   Cheers,

   Ray 

1. 
   BG | Apr 19, 2004 03:36pm | #12

   Joinerswork,

   Oh yes, I meant jiggle not giggle (damn hippies...lol)

   The Harvet Table article by Becksvoort that tatlin alluded to is perfect.  It addresses exactly what your saying about rounding under the top...and moving the center of the barrel joint up an 1/8" and over toward the leaf a 1/64" (as opposed to under the quirk).....(when I screw it up I'll blame it on wood movement)

2. 
   BG | Apr 22, 2004 08:42pm | #13

   Joinerwork,

   I wanted to ask your opinion. I think I screwed up.  I did the roundover on the top with what I thought was a 1/2" bit.  I needed to buy a cove bit and in the process found out my roundover bit was actually 3/8" so I went with it.  I centered my hinge barrel 3/8" down from the quirk...and 3/8" in from the edge.  I used the router and chisels to set the hinges to the proper depth.  When the sides are down on the drop leaf table the mortice for the hinge shows.....in other words..the lip on the leaf is not of sufficient height to hide the hinge mortice.  Is this because I used 3/8" roundover and cove bit?.....would it not of happened if I had used a 1'2" set?  thanks 

1. 
   joinerswork | Apr 23, 2004 04:10pm | #14

   BG,

   Go back and reread my post #3 on this thread.  As I described, centering the hinge pin on the radius line of the quarter round will put the edge of the leaf even with the bottom of the top when the leaf is dropped.  To hide the hinge mortise, the hinge pin should be moved closer to the corner of the top.  This has the effect of sliding the leaf up higher on the hinge leaf, hiding the mortise. 

   The cutters I normally use are about 3/8", as this size is about what I've seen on old work.  Larger cutters will not change technique of where to place the hinge barrel in relation to the center of the quarter round, but will give a smaller fillet on the edge of the top and leaf, and leave more "meat" around the barrel of the hinge after it is inletted.  I've used cutters as large as 3/4" r. for a harvest table with a heavy (1- 1/2") top.  It just moves the center of the hinge further away from the edge.

   Hope you tried this on scrap first? Or are you of the "lets do SOMETHING,  even if it's wrong" philosophy? ;-)

   Good luck,

   Ray

2. 
   BG | Apr 23, 2004 04:44pm | #16

   Joinerswork,

   Nope, I'm a trial first kinda guy....some of the time...kinda. I did run some sample cuts but did not practice the mortice cuts.  However, after reading your #3 again, I think I can salvage the situation easily.  I did cut a grove with a bit of play for the barrel on the underside of the top....and I've only driven one screw on each side of the hinge for testing the fit.  So If I move the hinge toward the drop leaf side a bit it should hide the mortice a bit better...

   To be honest, I'm considering this whole table top to be an experiment to learn from.  The cherry I was able to buy for this top is pretty crappy and I may buy more cherry when they get a new shipment and start allover.  The base is fine with double flaired mahogany tapered legs and with a nice top should look pretty good.

   thanks

3. 
   ian | Apr 23, 2004 04:38pm | #15

   BG

   If you can wait a day, it's near midnight here, I'll post the layout notes and diagram included in the article I posted an extract of earlier. 

   Ian

4. 
   BG | Apr 23, 2004 04:58pm | #17

   Ian,

   Thanks, that would be great.  The plans I have called for a 1/2" rule joint and when I found out I had a 3/8" rounder over bit it kinda through me.  I modified the plans in that I figured the radius should be 3/8" from the quirk and the edge....but I wasen't sure if the 3/16" shoulder from the roundover bit should be modified (maybe 1/4 or 5/16") to accomodate the 3/8" quarter round.  In other words, I don't understand all the aspects of this joint yet and the more I read and experiment the more I'll own it.  thanks

5. 
   ian | Apr 25, 2004 01:57am | #18

   Message 19 was a stuff-up, so I've deleted it.  here goes again

   BG

   prepare both edges as for an unsprung butt joint .  You'll need to read the rest in conjunction with the picture

   Dimension A – thickness of the hinge (from pin centre)  Scribe the lower edges of the top and leaf to this measurement on the ends and sides

   Dimension B – depth of top fillet, variable – the orignal author suggests not less than 3/16 in – scripe the upper edges of the top and leaf to this measurement

   Radius R – measure from your hinge – B = top thickness - Radius - Dimension A   Line C is established from the radius scribe line C on the edges and along the bottom of the leaf, the top of the table, and on the underside of the table top.  Note: if you're lucky you'll have a router bit the exact size.  The radius on the top should be very slightly smaller than that on the leaf.  The original author suggests using a scratch stock or sanding to achieve the required fit. 

   the intersection of A and C gives the hinge centre projected to the side of the tabletop.  scribe the curve from this point.

   Cut the tabletop first and work the leaf to fit

   Ian

   
6. 
   BG | Apr 25, 2004 03:06am | #19

   Ian,

   thanks for the post, I'm going to save the pics and article on my 'how to' folder.  I'm going to grab some scrap stock and practice a few of these joints.  I want to see if I can remove the bering on my cove bit and cheat a bit on the depth of the cove..except at the ends...and then slide the hinge over toward the leaf to get a tight fit on top and a hidden mortice when hanging down.  should be fun....

3. 
   ian | Apr 18, 2004 01:47pm | #3

   BG

   the attachments may help you visualise the setup

   Ian

   
1. 
   BG | Apr 18, 2004 02:27pm | #7

   Ian,

   Thanks for the pics...anyone reading this post will be grateful also I'm sure....lol.  These are the kinds of discussions I really relish on here....the art and science stuff.

   Whose hands are in the pics? Do you Know?

   thanks 

1. 
   ian | Apr 18, 2004 02:58pm | #8

   BG

   the source is  Fine Woodworking on Tables and Desks (Taunton 1986) pp28-31.  The chapter is a reprint from FWW #18 (September 1979) pages 66-69 – in the B&W days.  The original author is Alasdair Wallace, so they may be his hands.  Wallace cut his joint with his "grandfather's Stanley 45 and wooden molding planes"

   BTW it's recommended that you get the hinge BEFORE cutting the joint.  If you want I can post more of the article, especially how to layout the joint, but I'm a bit reluctant to on account of copyright. 

   Ian

4. 
   tatlin | Apr 18, 2004 10:30pm | #9

   Another reference is Chris Becksvoort's article in FWW #159, December 2002, "Harvest Table." While discussing various options of apron constructions for the drop leaves, he goes into detail installing the rule-joint hinge. Its a concise & well illustrated article, enough to give one confidence I feel.

1. 
   BG | Apr 19, 2004 12:01am | #10

   Tatlin,

   I think I have that issue (finally, I have one that counts), I'll check it out.  thanks