Thread: Fibonacci/Golden rule question

Originally Posted by redx

coffee table 900mmx520mm
This is the ratio of 1:1.618 worked out by the ancient Greeks
I have applied it to determine the length and width of the table top

900 / 520 = 1.731 so for your table top to be 1:1.618 it would either have to be 900 x 556
or 841 x 520mm.

Graham Blackburn's fourth volume in his Illustrated Workshop series 'Furniture Design & Construction' (2014) covers the Golden Mean (aka Golden Rectangle) very well with many useful examples in classic and modern furniture design.
He shows how every dimension in a piece of furniture can be ruled by the 1.618 ratio.
Eg.
IMG_20180410_102622-1439x2559.jpg

V

Originally Posted by redx

Hi,
I'm building ourselves a smallish coffee table 900mmx520mm which will have square legs, each leg being tapered on two sides. In designing my table I am having awful trouble deciding what thickness the legs should be and what degree of taper they should have so that I end up with something that was proportionally pleasing to the eye. On researching "proportional design" I found a whole lot of info on the web about the "Golden Rule" or "Golden Ratio", and the "Fibonacci Rule". This is the ratio of 1:1.618 worked out by the ancient Greeks and is the ratio used in good furniture design. I'd never heard of it before but after reading about it I understand it's importance and what is does. I have applied it to determine the length and width of the table top, but I'm wondering how I would apply this Golden Ratio to determine the depth of the skirt rail (?) and the thickness of the table legs. One website said the rule could be applied to determine the size of all these, but didn't explain how.

So now I hope someone on the forum will understand my question and can explain how to apply this rule to my table legs, please?

You need to remember that a coffee table is about 450 mm high viewed from two perspectives.
one is standing eye height -- about 1.6 m above floor level
the other is sitting -- between 800 and 1000 mm above above floor level.

the resulting perspective will distort the shape of your table and should be allowed for in the design if you are looking to use the golden ratio.
Ideally the golden ratio would be applied to one of the two viewing perspectives, and not the orthogonal elevations.

Originally Posted by FenceFurniture

900 / 520 = 1.731 so for your table top to be 1:1.618 it would either have to be 900 x 556
or 841 x 520mm.

Thanks FF for pointing out the discrepancy, I'll adjust my dimensions to suit.

Originally Posted by dubrosa22

Graham Blackburn's fourth volume in his Illustrated Workshop series 'Furniture Design & Construction' (2014) covers the Golden Mean (aka Golden Rectangle) very well with many useful examples in classic and modern furniture design.
He shows how every dimension in a piece of furniture can be ruled by the 1.618 ratio.
Eg.
IMG_20180410_102622-1439x2559.jpg

V

Thanks dubrosa22 for providing that image from Graham Blackburn's book. I can see now how you apply the ratio to the various parts of the table, so you have answered my question nicely. Many thanks.

Originally Posted by ian

You need to remember that a coffee table is about 450 mm high viewed from two perspectives.
one is standing eye height -- about 1.6 m above floor level
the other is sitting -- between 800 and 1000 mm above above floor level.

the resulting perspective will distort the shape of your table and should be allowed for in the design if you are looking to use the golden ratio.
Ideally the golden ratio would be applied to one of the two viewing perspectives, and not the orthogonal elevations.

Thanks Ian, I'll take your good advice with me back to the drawing board.

Originally Posted by redx

In designing my table I am having awful trouble deciding what thickness the legs should be and what degree of taper they should have so that I end up with something that was proportionally pleasing to the eye.

45mm square, tapering to 30mm square. Not basing this on any ratio, just from having made hundreds (might be up to thousands by now) of chairs and low tables.

One third does generally seem to be a nice taper and it scales up to thicker legs for dining tables quite well.

Before I make anything, I usually make a small scale model. Usually just out of plywood, mdf, polystyrene and cardboard. Hot melt glue to hold it together. Modify parts till they look right. Keep every measurement to scale.

My thinking on the golden ratio is that it’s ok on some ocassions, but stick to it slavishly and you will be making boring, unimaginative furniture. It’s like the rule of thirds in photography - every student is taught it but talented photographers rarely stick to it.

This sort of thing is why I love SketchUp so much. It takes a bit of little bit of learning to get up to speed but it’s invaluable for figuring out how something will look before making any cuts. YouTube has a ton of videos on using it if anyone is keen to have a play.

Originally Posted by Arron

Before I make anything, I usually make a small scale model. Usually just out of plywood, mdf, polystyrene and cardboard. Hot melt glue to hold it together. Modify parts till they look right. Keep every measurement to scale.

that sort of scale model is called a maquette. The model can be as simple as heavy paper or cardboard through to polished wood and leather.

I too find the technique invaluable as it allows you to easily look at a design from many angles and perspectives before settling on a final shape to put into sketchup.

Originally Posted by Arron

My thinking on the golden ratio is that it’s ok on some ocassions, but stick to it slavishly and you will be making boring, unimaginative furniture. It’s like the rule of thirds in photography - every student is taught it but talented photographers rarely stick to it.

:WHS:

Thanks everyone, I really appreciated all the interesting comments and good advice. Your replies have been a great help.

Cheers,
redx