Monday, December 6, 2010

Seat (Part 3)


I had a busy weekend and only one morning to work in the shop.  That caused me to rush, and that turned out to be a mistake.  

I purchased the rest of my wood this week.  I bought some 8/4 walnut for the back legs, 8/4 maple for the rocker accent, and a sheet of Russian birch plywood for the rocker jig.  The headrest and arms call for 10/4 stock, but Crosscut Woods didn’t have any in that size.  I had to settle for 16/4 stock.  This is much thicker than I need, but I can always resaw it, and use the rest for other projects.  I also received the tools that I ordered:  the bed extension for my lathe, a dowel plate, and the 1/2” rabbeting bit.

Now that I had all of the materials I needed, I was anxious to get started.  I put the standard base back on my router and added the offset base that came with it.  The offset base is used to stabilize the router so that it doesn’t tilt when routing the edge of a board.  I inserted the rabbeting bit and adjusted the height to 1/2”.  


I didn’t mention it before, but I use a WorkMate bench as an assembly table.  A piece of plywood screwed to a 2x4 makes for a nice wide bench top when clamped in the WorkMate.  It’s just the right height for me to work, it’s mobile, and I can abuse it as much as I want.  I just sand it down once in a while.  For routing and sanding, I lay down rubber shelf liner on the bench.  This is inexpensive, it holds the stock steady, and it cushions the bottom so the wood isn’t scratched from the tool vibration.  To rout seat piece #1 (left hand side of the seat), I placed parts #2 and #3 behind it.  These are used to keep the router offset base level.  I also clamped on a scrap piece of wood where the router bit will exit to prevent tear out.  I found that jointing this scrap piece helps to ensure a tight fit.  Before I jointed the piece, I experienced some minor tear out.



One complaint I have with my new router is that it doesn’t contain a light like my old one.  This makes it harder to see exactly where the cut is being made.  I had to get my face right down where the action was happening to see that I was cutting in the correct place, so I wore a full face shield to protect myself.  It worked fine.  When you first engage the bit into the wood, it has a tendency to pull to the left.  In the front leg slot, if the guide bearing isn’t touching the wood, this means your bit could be pulled outside the slot and that would not be a good day!  I simply started my cut a little to the right and kept a steady hand in the router.  I moved it slowly into the wood, and then gently moved it back to the left once the guide bearing was in contact with the slot.  After routing the top rabbets, the piece was flipped over and I routed the other side.  You can see the results of the seat joints here.  I then did the same with the #5 piece (right hand side of the seat).  I had one joint where a chip was chewed out just due to the grain of the wood.  Fortunately, it is on the inside, so when the leg is joined it will not be visible.



As I said earlier, I decided to connect my seat pieces using dowels.  Maloof used 1/2” x 3” dowels.  I couldn’t find any 1/2" dowels at most places I looked (I did find some at Rockler later), so I bought some maple dowel stock and ordered a dowel plate (Charles Brock recommended this on his website).  The dowel plate is a neat tool.  You cut the dowel to length, and then chamfer the dowel ends just like a pencil sharpener.  It takes very little effort.  Then you hammer the dowel through the appropriately sized hole to cut flutes down the sides.  The flutes help to spread glue evenly for a stronger bond.  Hammering the dowel can deform the end, so I suggest doing the fluting first, and then chamfering the ends.  When I drilled the holes in the seat, I went in to 1-1/2” depth on each side.  This should allow for a 3” dowel, but to allow room for glue, I cut them at 2-3/4”.  I needed 12 dowels total, so one 36” piece of stock was all I required.  The completed dowels look like this.




I didn’t review the instructions before I started, so after routing the joints and making the dowels, I was very excited to glue up the seat.  Unfortunately, the actual next step is to mark the seat pattern and cut out much of the material on the bandsaw.  Doing this initial shaping saves a lot of effort in hogging out the seat to form the derrière shape.  Skipping this step isn’t a fatal mistake.  The seat can still be sculpted, but it will take more work on my part.  People that make chair seats using slabs rather than coopered pieces have to do it this way.  I’m just mad at myself for forgetting.  Lesson learned:   Always review the instructions!

This is where things started to come unglued...literally.  I began gluing the dowels and seat pieces together.  Pieces #1 and #2 went together with no problem, but when I put pieces #4 and #5 together the joint wouldn’t close.  OMG!  I instantly realized that my dowels were too long (or my holes too short).  I still don’t know how this happened, but I didn’t have time to dwell on it because my glue was quickly drying.  I grabbed a large screw driver and pried the pieces apart.  This gouged the parts, but I made sure it was along the top where the material would be sculpted out.  I used a razor sharp pull saw to take about 1/4" off the ends of the dowels (working too fast and cutting my finger in the process) and then hammering the pieces back together.  This time the joint closed, and I managed to keep most of my blood off the wood.

After a little stop for first aid, I came back to the shop.  To avoid the same problem with the other joints, I sawed 1/4" off of the remaining dowels and chamfered them again.  I completed the glue up to piece #3 with no problems.  I used about 6 clamps to put pressure on the seat joints and left it to dry overnight.

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