Replies

1. 
   johnhardy | Aug 20, 2004 08:00pm | #1

   I haven't seen specific examples of this joint in books. But from what you describe it sounds like this is a spline which is shaped like part of a dovetail. If the spline is thicker on one side, and the thick side is at the back of the spline, the spline would look like a butterfly when completed. The difficulty I am having is picturing how you would cut the mitered joint to receive such a spline (which would have to slip into the joint from the side, rather than simply slide straight into the cut). I've used splines to reinforce mitered joints for coffee tables and used a jig for my table saw for the cut. The blade had to be fully raised to make the splines, since the jig took up half an inch of space between the top of the saw and the mitered corner ... which was standing on edge.

   I guess you could cut such a spline by hand, but unless you're very, very good this would not be tight enough to look good. I think it'd be much, much harder than hand cut dovetails.

   I've attached a photo of a coffee table I made which used ebony splines in the corners.

   John

   
2. 
   BG | Aug 20, 2004 08:32pm | #2

   Lynn,

   This was discussed about a year ago...I think there was a video on here which showed the jig....and run it through the dovetail bit on your router table.  The miters were glued up first.  Perhaps the video clip is still in the archives... 
3. 
   BArnold | Aug 20, 2004 10:49pm | #3

   Here's an example of a decorative butterfly joint:

   http://www.loggia.com/vignette/113b.html

   A shop I worked in last year had a specialty tool setup to make the joint.  Basically, it's a trim router with a small dovetail bit that is moved upward past the opening in the fence to make a cut approximately 3/8" into a joint.  It's got an air-actuated lock-down mechanism to hold the workpiece.  The 'butterflies' come in plastic or wood (maple) and are slightly tapered so they pull the miter joint together as they are driven in.  In this case, they are not really intended to be a decorative element, but more for strengthening the joint.

   Bill Arnold

   Food for Thought: The Ark was built by amateurs; the Titanic by professionals.

1. 
   lynnroy | Aug 21, 2004 05:38am | #4

   Thanks Mr. Arnold that is exactly what I was looking for. I also located a great discription of a technique to accomplish the keyed joint in Gary Rogowski's book on Jointery.

   Thanks

4. 
   billsams | Aug 22, 2004 02:19am | #5

   Lynn,

   here's another link for a use for butterfly joints. I used curly maple for the butterfly in walnut handrail. These particular joints also have a walnut vertical spline for holding the joint from side to side movement. Butterfly's wereccut on table saw in a 2' long peice, then sliced, traced them on the walnut and chiseled away.

   have fun

   Bill

   http://www.jwsjoinery.com/jws/staircasing2.htm

1. 
   lynnroy | Aug 22, 2004 04:16am | #6

   Thanks that is one inspiring site. I especially liked the way you used the grain for contrast on the handrail.

   Lynn