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Sunday, October 20, 2013

Greene & Greene Blacker House Office Chair - Part II

I'll work on the base first.  The seat was a bit too high on the chair fitting rig.



The swivel base was in the "mid" position so that one could raise or lower the seat about the same distance.  I decided to keep that setting but lower the seat somewhat by modifying the legs so that the bottom of the leg is flat.




I designed the top of the leg to have a cloud lift detail - a very Greene and Greene motif.  The cloud lift has a sharp inside corner.  I decided to define this inside corner with the table saw.  I first band saw part of the front then cut the inside corner with the table saw:



That flat is not too appealing, but it will get rounded over with the template and flush trimming bit.  Ok - so, I figure I'm pretty smart and I'll try to flush trim the tip without a backer by doing a very slight climb cut at the very tip.  Ooops!  Did not work!


Fortunately,  I left quite a bit of extra wood on the other end.  Oh yes, I had pre-drilled the holes for the wheels.  Since I had to redraw the profile of the leg farther back I had to drill another hole for the wheel.  This left the old hole in place which I plugged up with some maple.  Hopefully no one will notice (except for everyone on the internet who happens to read this blog!)


On my second attempt I clamp an MDF backer board to the bottom, flush trim the tip, then remove the forward clamp to flush trim the remaining part of the top:



Notice the blue tape.  I like to put tape on the template for the first pass to hog off most of the material which is likely to result in some burning, remove the tape and run a second pass where I am removing very little wood with no burning (hopefully).

The flush trim bit does a nice job but some wood is left on the inside corner which I remove with a shoulder plane and chisel making sure I go across the grain:


Next I cut the leg to final length and then cut the dovetail on the tablesaw.  I figure that a 17 deg dovetail seems to do the trick:



I hand plane the sides of the legs and use a file and sand paper up to 180 grit on the top of the leg.  Here is what they look like:



As you can see, the dovetails seem rather loose at the bottoms.  However, the metal flares out at the bottom.  The dovetails are actually pretty tight and I need to use a hammer to drive them home.

The next step is to install the quarter round pieces to hide the metal hub.  Or at least I thought they would be quarter round pieces without thinking too much about the shape.  As a test I glued 4 square blocks of cherry together with paper in between and turned them on the lathe.  After separating the pieces I quickly discover that quarter round pieces will not work.  I need circular arcs that are less than quarter round pieces.  I take one of the blocks and use a hand plane and chisel to define the desired shape, which you can see below on the right:


Well, the lathe will not work.  I guess its time for some hand work.  So I grab the bubinga blocks and determine the desired arc:


These blocks are not long.  The safest way to cut away most of the waste is with the band saw.  I am making a 45 degree cut here:


Next I clamp the piece and use a rasp across the grain to hog off most of the waste, a hand plane with the grain to smooth the piece along its length, followed by a small file and sandpaper:






Now I glue the circular arcs onto the base.  Note that I had hand planed the two reference sides before shaping so they are ready for glue up.  The legs are about four inches wide.  I glue the top 2.5 inches of the arc pieces since the grain is running in opposite directions.  We need to allow for wood movement and I figure 2.5 inches is pretty common for tenon widths so it should be fine here.


The nice thing about those blocks is that they force the legs into 90 degree positions.  After the glue dries I then screw on a bottom plate (not shown) with #14 screws that screw into the dovetails.  I also screw into those dovetails from the top as well.  Those screws from below and above secures everything very well.

Those legs are not moving!


When I am ready for finishing, I will round over the edges, wet the wood to raise the grain, then perform final sanding with 220 grit.  However, I'll quit here.  Time for a beer.

Wednesday, October 16, 2013

Greene & Greene Blacker House Office Chair - Part I

Ok - first thing first.  All this time I've misspelled "Greene & Greene" as "Green & Green".  Funny how all along I've read "Greene" but then turned around and spelled it as "Green" - my brain simply filtered out the trailing "e".  This makes me wonder what else my brain has been filtering out lately!

Here I am transferring the final settings of the chair fitting rig to cardboard.  I determined the ideal height of the chair, depth, as well as the splat curvature.  Because there will be inlay the splat needs to be of necessary thickness and rigidity.  This rules out thinner laminated strips for the splat.  Consequently, the goal is to restrain the curvature so that I can use 8/4 lumber.



Notice how the bottom of the splat curves inward to help define the lumbar area above.  This means an angled tenon at the bottom.

Next step is drafting.  I have a large drafting table (about 40" x 74").  I draft a plan (top) view, front view and side view on a single sheet.  This is an important step as I try to answer as many questions as I can.

Here is the front view.  Note the familiar Blacker House splat design:


Here is the side view:


Here is the plan (top) view:


Next I create my templates directly off of the draft.  I trace the curves using plain ole carbon paper onto the plywood.  I used 1/8" plywood for most of the templates.  For those templates that I will use on a router table or shaper, I use 1/4" plywood which I will later transfer to 1/2".


Most of the lumber comes from a single piece of 8/4 bubinga except for the front and side rails.  I purchased a separate piece of 4/4 bubinga for those.  This 8/4 brute is heavy.  I cut it down to rough mill size.



Fine wood is like fine wine.  It needs to breathe!