Saturday, July 21, 2012

Anatomy of a Leg

     Well, I thought that the title might pique your interest but sorry to disappoint you, it's going to be about table legs.  This one here in particular:

Walnut Table Base -- Leg Detail
     For this commission the legs need to be strong and have some mass to offset the Travertine tops.  Another consideration for this design was that the base of the table should not be so large and overpowering that it would hide the floor.  I was given a photograph of a table they liked which had large, square legs so that's what I went with.  To save material costs and also give the base a lean appearance I decided to make the legs shown above.  The first step was to determine the widest possible pieces of sapwood free Walnut that I could yield from the material available.  This is the leg for the coffee table and the width is 4 3/8", the two end tables have a width of 3 1/2".  Speaking about the material, there wasn't enough sap free Walnut to get the aprons for the end tables so I had to special order more which should arrive Monday.
     Back to the legs, the first step was to mill the pieces and cut them to length.  A 3/8"  tongue and groove joint was milled into the edges and the assembly process was ready to be started.  I'm sure I've mentioned (complained!) about the heat.  I drink enough water to stay hydrated and will work in the shop in pretty much any temperature but the glue is a different story.  I need to work fast enough to make sure the pieces are assembled and clamped before the glue starts to set. The first glue up morning it was 82 degrees at 6am.  Here it is, ready to get it together:

Clamps, Glue, Cauls, Wax Paper, & Water Ready to Go!

Material Laid Out And Ready
     There was quite a bit of planning to determine which pieces would be joined together to form the legs. Coloration of the wood and the grain pattern was one concern but equally important was that the grain direction went the same way on both pieces.  That's because the legs will be planed after they are assembled.  That meant that the face grain of one side needs to flow in the same direction as the edge grain of the adjoining piece.  Because of the temperatures I was able to glue up four legs each morning even though the mornings got warmer each day.
     The first step to finishing the leg assembly after glue-up was to scrap the glue from the joint:

Glue Scraper

     This was followed with my favorite finishing tool, my Bronze # 4 Smooth Plane from Lie-Nielsen.  I really don't think there's a better tool to get the type of finish I'm after.

Smooth Plane 

     As usual, there will be some unruly grain that even the Smooth Plane set to a fine cut and small mouth had a hard time taming, that calls for a card scraper.

Taming the Unrulies!

     Now comes the time when furniture construction can be artistic.  There are ways to display the grain of the wood to your advantage.  For these legs I wanted the grain to flame upwards from the floor.  You may have noticed in the first picture that there are letters stamped into the tops of the legs, this is to help keep things organized.  Chalk rubs off and pencil marks can be difficult to erase.  I use a set of machinists letter stamps to mark the mating parts.  Once that was done it was off to cut the mortises.
     Strength and stability are required to support the Travertine so I opted for full length, 1/2" wide mortises.  They are haunched for at the top and bottom to resist any twisting and 1 3/8" long.  This is an operation where, although I've done many by hand, I call on a power tool to do the grunt work which I'll refine by hand.  There's a trick I use on the hollow chisel mortiser:

Depth Stop with Spacer

     This haunch is about 1/2" deep so I put a spacer block on the depth stop when cutting it.  Once the haunch has been cut on the top and bottom of the mortise, the block is removed and the rest of the mortise is cut out.

Full Depth Mortise

     The final step for the leg part is to cut the mitered piece that will enclose the open L-shape of the leg.  This began with first milling the material and then cutting it oversize on the chop saw.  This makes it easier to handle when cutting the angles on the tablesaw.

Rough Cutting 

     It wasn't something I liked hearing when I talked about the quality of Walnut available these days to the guy at the lumberyard.  He kind of shook his head and said "Walnut's been a different animal lately" or words to that affect.  Maybe the demand is up or the supply is down but it's been difficult picking out the pieces I'd like to have.  In any case, once they were rough cut it was time to miter the edges at 45 degrees.

Inside Leg Pieces, notice the MDF

     Whenever I have an exact or tricky cut to make I'll make the set-up on the saw using some MDF for my sacrificial pieces.  Much rather make my mistakes on that then the Walnut!  I need 4 of these pieces for the coffee table and 8 for the end tables.  For the end tables the piece I found was wide enough to yield two pieces by flipping it over after the first cut.

Two Pieces from One Wide One

     This is a natural stopping point for this project.  The mortiser is set up to cut the mortises in the end table legs but I won't know their size until I get more materials for the apron on Monday.  It's pretty hot out there anyway and I don't anticipate any problems making them within the time frame we agreed on.  May be an opportunity to work on the boxes again!

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