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.

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!

Designing A Comfortable Chair - Part II

I mentioned in my previous post about a cool chair fitting rig described in Fine Woodworking issue #96 (Oct. 1992) titled "Design a Chair that Fits like a Glove" by Glenn Gordon.  I am designing a swivel office chair for a client.  I adapted the chair fitting rig in that article for a swivel chair:

The hardware for the swivel office chair dictates some parameters such as lean back (which is 3 degrees).

The part that I copied from the article is the back splat fitting assembly:

In the above photo we see how the assembly can be tilted back as necessary with the use of hinges.  However, a way is needed to support the assembly - the first photo above shows how the assembly is supported using plywood bolted to the sides of the side rails and a top piece that is clamped to support the back assembly.  It works, although there is a lot of weight overhanging the back of the chair which makes the chair want to lean back too easily when sitting.   Not sure how to get around that.

For the final chair, the back splat will meet and mortise into the top crest rail.  The crest rail will be proud of the back splat about 3/16" of an inch.  With the chair fitting rig I simulate this fact by clamping a 3/16" plywood to the top back support.  The goal is to make sure that the 3/16" bump does not end up digging into the client's back - very important since the Blacker House arm chair I built last year has this issue - the bottom of the crest rail digs into the back a bit and is not very comfortable.  Lesson learned!

Another question is what distance must the wheels be from the center for stability?  I drilled a couple holes so that I could test different distances for the wheels:

Designing A Comfortable Chair

This past spring I spent a fair amount of time on our new fence.  I live on a corner residential lot and the new fence wraps around 3 sides of our lot.  We went bird crazy and cut out barn swallows in the fence panels.  Actually, let me clarify.  My wife cut out the birds!  Here is one section of the fence:

Now imagine 36 sections of fence with anywhere from 2-5 bird cut outs in each section.  I still need to finish the 6 gates but that will be an ongoing process for now.  After finishing a small project for a client it is time to get back into the shop for my next project.

I am now working on a swivel office chair for a customer.  The chair will be inspired by the Green & Green blacker house arm chair. The back splat, crest rail, and the various ebony plugs and splines will borrow from the arm chair.  The base will use swivel office chair hardware with 4 legs dovetailed into the hardware.  No arms.

A year ago I built as close a reproduction of the blacker house arm chair as I could based on various photos I acquired here and there.  I think I got pretty close:

Now, I'll be honest.  The chair is not the most comfortable chair I've sat in.  Of course, chairs in many ways are like shoes and should be custom fit for each client.  When I sit in this beautiful chair I find that the bottom part of the crest rail digs into my back somewhat.  My first reaction is perhaps I need to make the entire back sweep farther to the rear, even though the chair back already has a pretty well defined rearward sweep.  Since the customer wants the back to be like the blacker house arm chair it is important that the back be comfortable for the customer as well as look beautiful.

There is an article in issue #96 (Oct. 1992) of Fine Woodworking titled "Design a Chair that Fits like a Glove" by Glenn Gordon.  The article has a very cool chair-fitting rig.  I may build one for this project.  In the meantime, I quickly hacked together this setup (I still need to attach the swivel base):

It is not nearly as fancy as the rig in the article.  Nonetheless, I find it pretty revealing.  The shape of the splat I borrowed from my couch.  The couch is a new Scandinavian style couch with great back support and curvature.  I took some 12 gauge electrical wire and shaped it to the shape of the back of the couch.  I then used the wire to quickly draw the curve on some 8/4 lumber.  It is a very good starting point.  I can move the  entire back forward or rearwards as well.

For the crest rail I've tried 2 orientations.  The first orientation is where the crest rail sweeps back following the curvature of the splat, similar to the blacker house arm chair:

The splat has nice lumbar support.  However, the bottom of the plywood crest rail sticks out which is very noticeable when sitting.   I tried moving the entire back forwards and backwards and I still experience the bottom of the crest rail digging into my back a bit.  Next I straightened the crest rail so it is more vertical and in line with the back of the splat rather than the front:

With this scenerio my back rests upon the entire crest rail rather than the very bottom of the crest rail - which I find more comfortable.  What kind of design follows from this?  Here is an absolutely beautiful chair designed and built by master craftsman Jeff Miller where the back of the chair sweeps forward at the top rather than rearwards as with the blacker house arm chair:

So I will explore the forward sweep in the context of the Green & Green design motif.

Green & Green Settee - Finished

Here is the Green & Green inspired entry-hall settee fully clothed just before delivery.  Fun project!

Green & Green Settee Part XVI

The last element for the settee are the rail brackets.  The joinery part has already been done and they now consist of rectangular pieces of cherry:

All that is left is the shaping and installation.  A trip to the bandsaw quickly gives them a recognizable form.

 

I use rasps, files, sandpaper to smooth the surface.  There's no right or wrong - just go with what looks good.  I also round over the lip.  I install a small dowel and it is now ready for installation:

The settee is ready for finish!  Although freshly sanded and prepared cherry is rather light and brownish and can be somewhat blotchy immediately after finishing, I sincerely believe no stain can match the natural patina of quality cherry over time.  I explained this to the clients and they agreed.  I knew of one fellow who wiped ammonia directly onto a cherry table.   Afterwords it was a toxic and somewhat scary thing that had to be neutralized.  It actually did accelerate the patina process but I had to wonder if all the ammonia actually got neutralized.  Not sure if I would want babies hanging around the table.  Fuming may work but I've read that this process takes quite a bit longer.  I'll defer to the natural process of light.

I don't have a photo of it, but I made a drop-in seat out of 12mm baltic birch plywood.

For finishing I use a tung oil / varnish wipe-on finish made by Old Masters.  I've used this product before and I'm quite pleased with the results.  There seems to be a bit more varnish in the blend and they use real tung oil.  I wipe on 4 coats and call it quits.  The customer wants a more natural look so I do not use too many coats.  Then off to the upholsterer.  The last blog will have a photo of the final result.

Green & Green Settee Part XV

After glue-up I went ahead and sanded the whole piece with 180 grit.  I'll spare you the gory details of sanding.  I had either handplaned or pre-sanded (120 and 150) most of the parts before glue-up, so this sanding phase wasn't too bad.  For a few spots I had to dip down to 150 to touch up a dinged area here and there.

Next I cut the groove for the crest rail ebony spline.  There is a bit of trepidation taking a router hand held to a nearly finished piece:

I have only a 1/8th inch wide groove cutter (it may actually be a biscuit cutter, not sure).  As you see in the photo, I had to make two passes to get the width I wanted.  Unfortunately, I had some tearout, so I had to widen the groove a bit to clear that out.  I went very slow and removed very little to remove the tearout, which produced only fuzz but no tearout at the problematic area the second time around.  Unfortunately, the groove is a bit wider than I wanted, but it still looks fine.  The problem I think is that I went the entire depth with the first cut.  Next time I will take multiple passes, with the first pass shallow to avoid tear out.

I used my bandsaw and small Jet 10-20 drum sander to make ebony splines.

It is not an exact 90 degree angle where the top spline meets the vertical spline so I had to fuss with the top of the vertical spline on a makeshift shooting board using shims of paper to change the angle:

After using a coping saw to remove most of the ebony, I use a small coarse sanding drum on a dremel to level the ebony to where I can finish with hand tools and sandpaper.  The small sanding drum is very aggressive and the process goes quite fast.   I have a vacuum hose underneath (not shown for some reason) in an attempt to capture most of that gnarly ebony dust.

I also tackle the plugs, using the same process as I did for the arms in an earlier post.  Before installing the plugs I wet the entire piece to raise the grain then sand with 220.  Sanding around plugs is not a lot of fun so better to do so before hand.

I install corner glue blocks inside the seat area.  Glue blocks add a tremendous amount of strength to the piece:

 

I see the light at the end of the tunnel!