The Last Pieces!

I finished fabricating the last pieces today..  Wooohooo!


Click here for a Flickr show of the last couple of days, and today's grand finale: the arm and back rests.


All that's left now is final sanding, pre-finishing, glue-up, final finishing, and the metal tie rods between the legs.


Then, I turn to sales, while I get CNC fabrication going.

Jigs and splines

Here is a jig I made for gluing the book matched triangles together to make the 4 diamond shapes that comprise the seat.  Thin wedges fit between the pieces and surrounding stopping blocks to apply pressure to the pieces.  In this photo, I'm still using test wood, Zebra wood will follow.  I also made a jig to glue the diamonds together to make the seat.  I made that from one of the test seats, which was already of the correct geometry for a jig of this sort.  I cut some holes in the bottom of it, though, so I could keep an eye on the seams from both sides.  Finally, I tested a spline cut from Afromosia, cut with it's grain going the long way.  It split too easily, so I cut all the splines I will need for several chairs, with the grain going the short way, so that the grain bridges the joint.  The tricky part was to handle such small pieces safely on the table saw.  Click Here for a Flickr show.

Another test seat...

Click here for a Flickr slide show.  I laid out the pieces on some MDF the same dimensions as my Zebra wood, so that I could confirm the book matching of the grain and the efficiency of the layout.  Then I cut the pieces to rough size and used my tablesaw jig to make the finish cuts in about 20 minutes.  Then I used my router table jig to cut slots in the edges, 90 degrees at the flat connections, and tilted at the dihedral angle connections.  I put the new seat together with splines.  Sweet!  Since these photos, I've laid out and rough cut my Zebra wood.  Then I tried to cut the Zebra wood on the table saw in the jig, but the blade is not sharp enough for a clean, unburnt cut through the very hard Zebra wood.  I have to get a good crosscutting blade before I continue.  Drat.  Plenty to do 'till Monday; sand all the frame pieces to prep for finish (I have to find a dust free space to do the actual finishing), cut splines from Afromosia, build a clamping jig for gluing the seat components, cut out the back rest and arm rest pieces...  Still lot's to do, but I can see the end.  I'll post pics tomorrow of the book matched Zebra wood seat.  It's great :-)

Adding a pretensioning member (lag bolt), and making the seat

Click Here for a Flickr slide show.  I added a bolt through a potential breaking point at the bottom of the back support.  Then, I completed a revision to the profile of the "elbos" which had been bothering me for a while.  I had to hand carve the rounded bottoms of the arms to match the machined round shape running up the outside of the arms.  It came out very clean.

Also, after a failed attempt to build the seat with angles measured from the mock up and used to cut 8 triangles on the table saw, I got a terrific suggestion from shopmate Andrew Isley; build a jig that holds the seat component off the saw table at the correct finished orientation, and let the saw cut straight and the geometry can take care of itself!  I built such a jig and it worked perfectly on some test wood.  I also tested rounding the edges of the pieces on the router table, and discovered that the unsupported ends had noticeable "tear out" when the router bit emerged from the piece.  I'll solve this too, and also try splining together some of the panels, before I make the final seat out of the very expensive Zebra wood I milled from 2" lumber yesterday.

Meanwhile, in the shop's finishing room, I have prepared several finish samples on scraps of Afromosia, combinations of sealers, pore fillers, stain, and polyurethane or Tung oil; I need to get a beautiful finish I am certain I can produce on the 20 parts of this first chair, and be sure it dries correctly and so forth.  I am pretty sure I have a good recipe, but before I proceed, I will check in with Sandy's brother, a professional antiques restorer.

I've ordered a variety of little brass components from which I can make the tie rods across the bottom of the chair legs.  If these are problematic, I can do something with bicycle spokes and some of their fastening components. We'll see.

More Chair Progress

Lots of construction progress.  The frame is essentially complete, with just some joint fitting and sanding left to do.  I still need to make the seat, back and arm rests out of the finish material, which will be Zebra wood.  It has a strong grain that will be arranged to radiate from the center of the seat.  (In the photos, those parts are mocked up from plywood.)  The tops of the arm rest supports will be trimmed smaller and the arm rests will be tilted back a bit, parallel to the seat.  I also need to make the brass rod tie rods between the legs.  Click here for a Flickr slide show.

I've located CNC furniture fabricator 3 blocks from my shop, who I think will be able to make parts for the chair at a reasonable rate, time and money wise.  I also have discovered that one of my shopmates can do the CAD modeling for me in a day.

Tons to say...

I have lots of pictures and a lot to say about Burning Man... but not now :-)  I have been working steadily on the chair and must stay on task rather than spend a day or two editing photos and writing about "the Burn."  I'll get to it soon...