Green & Green Blacker House armchair - part X

Bracket details - and chair is finally ready for finishing!

There are 4 bracket details under the seat rails.  After building this chair I realize now that some things should have been done before the primary glue-up.   Fortunately, I did fit the bracket details before glue-up.  They were roughly shaped and fitted into a mortise in the front legs and fitted with 2 screws into the seat rail.  Consequently, the exercise going forward consists primarily of final shaping.  The hard part, namely the joinery, is done.  The pictures below show what has already been done.  If I build this chair again I may try using a floating round tenon to join the bracket to the leg rather than the square mortise as shown below.

Here we go with the final shaping...

Below I am using a very fine Japanese crosscut saw which I purchased from the Japan Woodworker years ago.  Works great for small and precise cuts.

Note the curved and rounded over lip - a subtle but important detail I think.

I had sanded the entire chair up to 220 grit before installing the plugs.  I only had to do some spot sanding at this time.  The chair is sanded and ready for finishing!

 

Below is the original for comparison.

The first thing I notice is that my brackets are a bit heavy.  I know that my front splines are heavy (due to a tool malfunction described in an earlier post).  I think my square negative spaces in the main center splat can be a bit larger.  However, I'm pretty satisfied with the results.  This is a tough chair to build!  The fact that much of the chair was shaped by hand will definitely lend it a unique quality which isn't necessarily bad.

Green & Green Blacker House armchair - part IX

Plugs (and more plugs), seat cleats, and polishing them splines.


Ok, with my estimation I came up with a whopping total of 86 ebony plugs (with the possibility that there may be 2 additional ebony plugs below the bottom side stretchers to give us a total of 88 plugs - however, I will ignore that possibility for this chair!)

There are 8 ebony plugs that hide the 8 screws that attach the 4  bracket details to the bottom of the seat rails.  Given that only babies and drunks would see those, I will simply use round mahogany plugs down there.  So that brings the total down to 78.  There are 2 ebony plugs on the back seat posts that hide the 2 screws that attach to the arms.  Those were installed earlier.

That leaves 76 plugs to be installed!

There are a couple ways to make and install ebony plugs.  I will not go into the various possibilities.  To make my life much easier I purchased a couple Lee Valley square hole punches - 3/16,  1/4, and 5/16.   These cover all the sizes except for 4  1/8 inch plugs on the front seat legs.  For those I simply used a small drill bit and chisel.  These small plugs give the appearance of securing the seat bracket details under the seat rails to the front legs.

To make the plugs I used a bandsaw and my Jet 10-20 drum sander to dimension the ebony into 3/16, 1/4 and 5/16 inch strips - although oversized about 10/1000" in both dimensions as recommended by various woodworkers out there.

Darrell Peart uses a disc sander to quickly round over the tips of the ebony strips to give it a pillow effect.  Since I do not have a disc sander, I used William Ng's method of using a cordless drill and some cushioned sandpaper stations - really saves the wrists in attempting to establish the pillow effect.  You can see him in action on youtube where he explains the process in more detail:

http://www.youtube.com/watch?v=HLopA6NF7dk&feature=related

Note that I had to borrow a neighbors cordless drill with a 1/2 inch chuck to handle the 5/16" ebony strips.  My cordless drill has a dainty 3/8" chuck.

Now, the course grit worked great, but I had problems in totally removing the course streaks with the finer grit using the cordless drill - especially for the 5/16" sized plugs.  Consequently, after establishing the pillow with the cordless drill and the course sandpaper (150 grit), I used my hand with a pendulum motion to remove the 150 grit marks using 320 and 600 grit sandpaper (not cushioned).  This went pretty fast.  I then took the plug to a buffing wheel to get the sweet polish.  I then cut the plug to about 3/16 - 1/4 " long.  Some of the plugs on the thin crest rail were a very light 3/16".

For the 2 side stretchers I had drilled a 3/16" hole and installed a round maple tenon from below to secure the center stretcher in the early stages of building this chair.  I now covered the top with a 3/16" ebony plug:

Now, on the original this may be a real ebony tenon - or there may be ebony plugs above and below to hide the real hidden tenon.  Not sure - and probably not too important in the big scheme of things.

Here is the very nice Lee Valley square hole punch in action:

Some of my plugs are a bit heavy, such as the one above.  At least they got personality!

Probably the most challenging exercise here is with clamping and getting the chair in a position to make pounding with the square hole cutters possible (without demolishing the chair!).  I had to be very careful when installing the plugs on the rather thin crest rail - using light taps.  This added to the time involved in installing all these plugs.  Installing 78 plugs took some time!

I also made templates:

After installing all those ebony plugs with a shiny buffed surface, the ebony splines looked very dull in comparison.  I decided they needed buffing as well.  I used my dremel with a buffing wheel and some buffing compound.  Boy did this make a difference!

Before installing the seat cleats I consulted a professional upholsterer on how to do this.  I will be using a drop-in sprung seat.  He gave me the dimensions of the cleats and the recommended clearances from the top.  The cleats are white oak and are 3/4" wide and are 1-5/8" from the top of the seat rail.  They are both glued and screwed on for strength.  I will provide him with a quality piece of 5/8" multiply birch plywood.  I will have about a 1/4" clearance on all sides of the plywood for the fabric.  Here is a picture of the cleats installed:

Note the corner glue blocks for added strength