Sunday, November 25, 2012

Installing the Breadboard Ends

Star Jasmine Flower
     Yesterday's work ended with the breadboard ends installed and the top ready for final shape and form.  I don't think I've shown the flower that serves as the inspiration for this piece.  It will be a real challenge to carve this on the drawer fronts and the panel on the shelf that will be at bottom of this table.  Like so many other things we do when working with wood, one slip of the chisel and all of the previous work could be wasted.  That's where what I used to tell my students comes in to play: "the difference between a good woodworker and a not so good one is that the good one has learned how to hide his or her mistakes".  There's a lot of truth in that statement.

     The process started by making the Ebony dowels used for attachment.  I have very little of the Ebony left but wanted to utilize what I could since it makes a nice functional yet decorative accent to the top.  I'm sure this wasn't OSHA approved but I needed to make some small blanks on the bandsaw.

Watch Your Fingers!
     After using a scrap for a zero clearance board I carefully sliced some pieces to just over 1/4" square. Then came the process of making the dowels.  Not as easy or straight forward process as you'd like to think it should be.  Much more than simply driving a square peg through a round hole and coming up with a round peg!  The literature tells you that for best results you should rive the wood to get straight grained pieces to start with -- not possible with my very limited supply of Ebony.  Here's the set-up and process in a nutshell.

Square to Round

     It begins with planing the blank into an octagon shape.  If you look at the picture, to the right of the block plane there's a bench hook with a groove in it that I use to hold the blank to plane it as needed.  My next step is to use a pencil sharpener to taper the end making it easier to hammer through the dowel plate.  That's the fancy looking piece of wood in the center of the table.  I managed to get just enough of the 1/4" pegs for the top, 6 short pieces.  Since I was at it, I used the smaller pieces that remained to make some 3/16" pegs as well.  Even though these are kind of small, they may work to peg the tenons for the apron. Now we get to prepare everything for assembly.
     First up was bringing the breadboard end to thickness.  I left the lay-out tape on the top and then surfaced the end.

Planing End to Size
     My thought was that as long as the tape is there to protect the top I could be a little more aggressive with the smooth plane.  As soon as the tape was cut, it was time to stop.  At this point the holes are drilled in the breadboard end only.  I wanted to draw bore these to create some mechanical pressure.  The first step was to use the 1/4", brad point used to drill the holes as a center punch to mark the holes on the top.

Transferring Holes
     The ends were clamped up tight to the top for this process.  Next, the breadboard ends were removed and I used a scratch awl to move the hole position about 1/32" inch towards the inside.

Locating Hole
 This was then drilled out, a piece of scrap wood was put under the hole to prevent tear out as the bit went through.

     The purpose of a breadboard end is to allow the table top movement inside the slot/mortise.  Wood moves across the grain due to atmospheric and humidity changes.  The only place glue is used is on the center tongue.  For this table, the center tenon is about 5" wide and the mortise it fits into is 1/4" wider on each side.  The same applies to the measurements for mortise and tenons on the outside. Essentially this will allow the table top 1/2" of movement inside of the slot.  Before assembly though, the outer holes need to be elongated so the wood can move as needed.

Marking Slots

     They are first laid out with the marking gauge, this is followed with a round file to elongate the hole.

Round to Oval (more or less)
     The dowels can either go completely through or stop before they come out of the other side which is my preference.  To assemble this a 4" wide stripe of glue was brushed on the center tongue and inside of the tenon.  I put a few drops on glue on the inside of the dowel holes of the breadboard with a toothpick before sliding in place.  Holes were lined up, Ebony pegs were inserted and then driven through.  For the center hole it's okay to have the dowel glued to the hole but since we're after some movement on the outer ones you don't want to glue them tight.  That's why I put just a spot of glue into the stopped hole.  For the outer holes I drive them about 3/4 of the way in and then apply a bit of glue to them.  Hopefully this is enough to only secure them to the upper part of the hole without gluing the tongue.  Draw boring works well to bring the end piece tight against the top.  Once the glue dries the dowels will be cut flush and the shaping will begin -- but that's for another day and blog.

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