On 11/18/2012 9:14 PM, Bill wrote:

This raises the question that has been kicking me around: Given a base
with only 4 legs of support at the corners (say, like on the Cedar-lined
chest you made for your daughter, only longer and wider),
wouldn't the frame be inclined to *sag* length-wise?


Sagging furniture, a function of its span, is indeed a major
consideration to take into account in designing and building casework.

I spent a goodly number of years noting and observing the effects of
span on antique casework, and the historical attempts to mitigate
sagging as a result of too great a span in furniture like sideboards and
hutches.

Each time I ran across a wide antique piece I really liked, it seemed to
suffer the ravages of sag due to its longevity ... drawers that no
longer opened or closed fully, and doors no longer coinciding with their
openings. This propensity for sagging was particularly apparent in those
type pieces made in the Arts & Crafts period of the late 1800 and early
1900's.

The obvious solution to sagging casework is to decrease the span, either
by making the piece less wide, something that does not always lend
itself to the preferred design, or by adding interim support.

One of the traditional ways to mitigate sag in these wider pieces was to
add middle legs:

http://www.jamesdewandsons.com/accen...-sideboard.php

Admittedly a beautiful and aesthetically pleasing solution, providing
you like the style.

When I decided to design and build a wide sideboard to my own tastes, I
totally discounted the idea of six legs. Not only did the addition of
extra legs not fit in with my preferred style, it also increased the
problems of situating a piece of furniture on floors that are not
perfectly flat.

I did a good bit of research into the matter in the intervening years
and it was not until I ran across an article in the Sep/Oct 1999 issue
of "Fine Wood Working" magazine, by Will Neptune, entitled "Sideboard
Strategies", whereby the author, a teacher at a respected woodworking
school in Boston, taught/proposed a four part, casework construction
method that was a bit unusual for traditional sideboard construction -
basically a dovetailed box, turned on its side, with legs attached to
the box, that I found a solution I thought I could live with.

In a nutshell, the basic principle of this particular casework
construction method is:

"If a case part joins another at a corner, dovetail it; if one part
meets along another's length, use multiple through tenons."

Since then I have used this basic principle, with some occasional
modifications, in quite a few pieces of casework, both furniture and
kitchen cabinets.

Careful studying the photos in the links below should give you an idea
of how to use this principle to mitigate sag in your casework:

http://www.e-woodshop.net/Projects13.htm

https://picasaweb.google.com/1113554...1917253 74850

https://picasaweb.google.com/1113554...2144547 81186

Resulting in:

https://picasaweb.google.com/1113554...0 36822986818

https://picasaweb.google.com/1113554...6579392 12162

Good luck, and let me know if I can answer any questions.

(If you can get a copy of the above mentioned article, do so ... it
covers using this principle in many more styles than what I show above)

--
www.eWoodShop.com
Last update: 4/15/2010
KarlCaillouet@ (the obvious)
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