Larry Ciesla

draw leaf table

This one minute video will show you how this draw leaf table operates:

Rather than going into a long and detailed explaination of how I built this table, instead, I'll focus on helping you understand how the table operates so you can design and build your own version.

Here is a color coded image of the table that I will use to explain the basic operation.  Notice first that there are two tops, an upper top in dark brown that is the actual table top, and a second top under the first that consists of three sectons:  a middle section in green and two draw leaves at either end in light brown.
The table with both draw leafs in the extended position.  Notice the key element of this design is that as each leaf is extended, when it reaches the end of its travel, it snaps into a position that is exactly level with the actual table top, effectively extending the length of the top.  In effect, each draw leaf must rise along a ramp system the thickness of the table top such that when it reaches the end of its travel along the ramp each leaf is at the same level of the top.  This is the key to the tables operation and I'll explain more about how this works a bit later.
One of the key reasons this can work is that the top actually floats on the table and is held in position by two pegs you can see here.  The pegs in the table top are not really drawn to scale.  In actual practice, I used pegs that were 1.25 inch in diameter.  The holes in the center section are actually slightly larger in diameter.  The fit of the pegs into the holes is key because they both must hold the table somewhat firmly in position, yet allow the top at either end to rise as either leaf is pulled out.  When the leaf reaches its fully extended position, it is the top that snaps back down as the leaf is extended past and no longer supports the top.
There are several things of note in this picture.  First, notice that the slide changes thickness from about 2 inches toward the middle to slightly less than 3/4 inch when it reaches the end of the leaf.  This change in dimension forms the "ramp" that allows the leaf to rise as it is pulled out. 

Second, notice that there are two points of contact that the ramp makes with the table base.   On the fixed center leaf, the ramp contacts the leaf at the point shown.  Note that it does not make contact in the notch that is cut thru the center brace thru which it passes.  The notch in the center is more of a side-to-side guide.  Note that the other place the ramp contacts the table at the bottom of the notch cut into the apron.  The depth of the notch in the apron must be extremely precise because that depth, along with the thickness of the ramp at the point of contact, are what establishes the height that the leaf will rise when it if fully extende or fully inserted.
Here is an exerpt from my shop drawings that shows the particular dimensions from the table I built. 
I used my tapering jig to cut the angle for the slider ramps.  This was an extremely fussy cut that had to be dead-on to also match the depth of the notch in the apron so the leaf would be positioned at exactly the same height as the main table top when the leaf is fully extended.

Here are a couple of pictures showing how the slides attach to the leafs and pass thru notches cut into either apron as well as a center divider.  There is enough room in the center divider to allow the slides to easily pass past each other, but not so much as to allow the slides to rack as they are moved in and out.

The second picture shows how the slides are secured to the leafs using screws and glue.  If you look carefully at the bottom image, you'll note that the slide extends to the end of the leaf.  Later, I trimmed the slide so it only sticks past the apron by about an inch, but during fitup, I left it long.

One other important thing that is not shown is a stop that I fabricated to not allow the slides to extend too far.  I made a couple of stop blocks that were screwed to the slides that prevent them from passing completely thru the center apron.

Here is the table just prior to staining.  These pictures show the two alignment holes in the center section.  Also note that in the bottom picture, the leaves are fully extended.  Had the top been in place, both leafs would have risen to be in exact vertical alignment with the top.
After finishing and almost ready to go out the door.  It's difficult to see, but you'll notice that the top of each slide appears to be unfinished.  That's because I've installed a thin, low friction UHMW tape to these surfaces to allow the mechanism to work with as little friction as possible. 

I don't have a picture that shows it, but I also installed several strips of UHMW tape to the bottom of the top itself.  As the leafs are pulled out, these strips effetively lift the top very slightly above the leaf so there is no wood to wood contact.