Tuesday, November 27, 2012

Forming the Top

Nothing Like a Hand Plane

     The breadboard ends are now secure, the Ebony has been trimmed, and it's time to shape this top.  I want to put just the slightest ellipse on the sides.  The top is 16 1/2" wide and just under 54" long.  Each end is brought down to 15 1/2".  To accomplish that the first thing I did was to create a template from MDF with the radius for one fourth of the top.  To locate it squarely, a straight edge was clamped across the width of the top to first draw the line on one edge, flip it over and get the other edge.  That's repeated for the opposite end and cut on the bandsaw.  To true it up, the template was clamped and a pattern routing bit was used so that all edges begin with the exact, same profile.

Step One of Shaping

     The reason I say I'm starting with the same profile is because there will be a lot of plane work to refine this shape.  The router is just the muscle to rough it out and it will never leave the kind of surface a plane or spokeshave will.  In order to take the lightest cut possible, the first passes were done with a very short pattern bit.

Pattern Routing

     You can see that it won't cut all the way to the bottom of the edge so after several passes with it, I swapped it for the longer bit you see on top of the template.  Once the cut is made with the short bit the template isn't needed any longer -- just use the cut surface of the edge as a guide.
     Next up is to bevel the bottom edge to give a sense of lightness to this piece.  You may recall that I laminated an additional piece to the bottom that was 5/16" thick.  I want this joint to be underneath the tabletop so drew a line 3/8" up from the bottom.  Arbitrarily I ended up measuring in about 3/4" to get the angle that looked good to my eye, turned out to be 65 degrees.

Checking the Angle
     Yes, it turns out to be a lot of planing but there's really nothing that compares to a hand planed surface.  If the profile had been square perhaps a table saw could have removed the bulk of the waste but with the interlocked grain of this Sapele, it could also have ripped  out a chunk!  I find that once I get a rhythm I can hold the angle all the way down.  Even so, I'll check every 4-5 passes to make sure I'm on target.

MDF Scrap to Prevent Blowing Out the End Grain
     The other visual thing to watch is the lines, as long as you approach the lines pretty much at the same time and keep the cut the same distance from them as you work you should be okay.  This was a bit unusual because of the bread board ends.  Generally you'd plane across the grain first which is the end of the board but in this case it isn't.

Entire Edge

     Here you can finally see the entire edge and probably notice the slight ellipse it has.  The taper is only 1/2" from the mid point to the end.  Just enough to add some character as far as I'm concerned.  My process was to use a jack plane first for the roughing work.  Once I got my rhythm I was careful to observe the shavings coming out of the throat.  I figure that if they're even all the was across I'm probably taking an even cut.  However, like I said I do check with the sliding bevel every 4-5 strokes.  As I approached the lines I switched from the jack plane to a smooth plane to finish it off.

     The final bevel is cut across the ends of the top.  To me, this is always kind of a magic part of the process.  You begin by drawing a diagonal line from the inside edge of the bevel to the corner of the piece.

Beginning the End Bevel
     As you continue to plane you watch as your cut gradually approaches the line you've drawn and the corner of the board.  If the picture above looks a bit odd remember it's a breadboard end.  You expect the end grain to be at the end of the board but no --- it's on the edge.  Must admit, looking at the picture threw me off!  As you continue to plane you watch carefully and soon you will have an exact corner.


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