Friday, September 30, 2011

Woodworks by John: Design Process

     In a recent conversation the subject of how to go about about designing projects came up.  Many times the client initiates the process with either sketches or pictures of what they want.  Some of them are so descriptive when they talk about their visions then that's all you need to get you going.  The technique that works well for me is that a design  can germinate in my mind for a long time which is then followed by rough sketches to visualize it.  That's how the design for the Dovetail Chair came about.  I built several mock-ups played around with the joinery, angles, dimensions, etc. and ended up with a set of chairs that are comfortable, stylish, and were awarded an Honorable Mention at the Design in Wood competition.
     We were watching an HGTV show that Vern Yip hosted about an urban condo they are planning to give away in Chicago.  He was talking with his assistant and mentioned places he likes to go to get design inspirations.  Can't quote it directly but what it boiled down to is that you never know what stays in your mind when you just observe things that may come out in a later design.  He's right!!!, as they were walking around in some recycled furniture store I saw a set of tables that inspired me for the ones that have been playing around in my mind for a long time now.
Initial Prototype
     If this were a project for a client I would refine it and present them with a drawing of the project.  If, as is the case here, it's a speculation piece or for personal use I like to play around with it in three dimensions.  You can use cardboard, MDF, or an inexpensive wood such as Poplar.  This photo shows the first general shape of these tables.  Their purpose is twofold, first as occasional tables that are just right to put by a sofa or chair and secondly to fill a blank wall space.  By placing them against the wall so together they will present a larger surface that could be utilized for .....?  I like the shape and size and have selected Walnut for the framework and Zebrawood for the insert.  The struggle has been with the legs.  Heck, you can find a four legged table anywhere so let's see what can be done with three!  Didn't want to have a "sea of legs" when they were parked against the wall.

    The first concept was to cut notches and attach the legs into those.  You can see I experimented with placement of them on the rear.  After doing that and looking at them for a while it just seemed awkward and bulky.  The next idea was to have the legs extend up, into the frame with an exposed and splined tenon.  This, on the other hand, looked too slim and fragile.  Finally, after seeing the tables on the HGTV show I came up with the design I like, that's the one in the lower right side.  Good thing too because the Popular prototype for the frame was running out of space!  The mockup leg is made of MDF and consists of a through tenon that is angled out 10 degrees to add stability and give a sense of movement.  In reality, there will be one centered in the short end and two across the back.  Good, you have the design, now, how are you going to build it?
     For the prototype, where only one thing is required it's no problem to work it out the best you can but when it comes to making three tables and nine legs plus the joinery it helps to have some type of consistent set up.  My work method is to use power tools to basically rough out what I can and then finish with hand tools to refine and fit every part into its proper place.
Mortising 45 degrees at the rear
The front through mortise was no problem.  The rear ones are cut 45 degrees to the back frame member.  I needed to make a jig that would hold the frame at that angle plus clamp down during the mortising operation.  This is the set up for one side, the clamp was re-positioned to the other edge for the others.

Now comes the mating part of the mortise, the tenons.  The legs were left long and the mortise will be cut longer than needed as well.  By angling my tenoning jig at 10 degrees every leg will cant out the same amount.  Each leg required two passes and are cut slightly oversize.

Cutting 10 degree tenons


After each tenon was cut, I used a rabbet block plane to fit them to the mortises as far as their width goes.  The length of the mortise is about 1 1/8" and the leg is currently 2 1/4" wide.  Each leg will be custom fit into its' location.
Trimming Tenons
There are several more steps to the legs.  After they are fit into their mortises they will first be angled on the front faces.  Then they'll need to be tapered to about an inch or so at the bottom so they will appear light and delicate.  Where they enter the table frame will be splined.  Basically that involves cutting two narrow slots in the tenon and then driving in a wedge to secure the joint.  You can see how it will look in the practice piece behind.

Prototype Leg
Here's another view of the mock up, do you agree that there is a sense of movement in the design?  I like how shadow and light will play on the angles cut into the front of the leg. In reality, there will be one leg centered on the front and two across the back.  I'll keep you informed as we go through this process. 

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