I thought it was about time I made myself a ‘Fibonacci Gauge’ and like most of us would I looked up on how everyone else did it. There were some great efforts made by fellow Jocks on the subject;

David made a good crack at it

http://lumberjocks.com/David/blog/1639

so did FJPetruso

http://lumberjocks.com/projects/37696

and my good buddy Karson

http://lumberjocks.com/projects/24528

Karson has his Excel spreadsheet for calculating gauges at any size. This is what got me thinking.

There must be a simple way to design a gauge of any size and as sure as pigs don’t fly there is.

This is my version of Fibonacci’s famous work (not to forget to give Pythagoras a big mention, after all he started it)

The ‘Golden Ratio’ as we all know is 1.61803399, the three dimensional one that is most pleasing to the eye.

To be used as a rule of thumb and not the be all and end all of proportions in design.

I have used FJPetruso’s labelling (A to H) on his project, this should help if anyone wants to compare blogs. I have also worked out the relationships between the points and they are shown on the diagram

The length of all the pieces and the distance between the pivots are all relative to Fibonacci’s workings as you can see from the above analysis.

Now to the meat of it all

First you need to decide on the width your calipers need to be at. Once you do that everything else will fall into place.
**Example**

I will do this in millimeters to keep it simple.

Lets say you want a caliper around 200mm wide, of course it will measure greater or lesser widths but it’s a general starting point.

So the distance FH=200mm

Now calculate GH where GH=FH/2.61803399, so GH=200/2.61803399=76.4mm

Now calculate FG where FG=1.61803399 x GH, so FG=1.61803399×76.4=123.6mm

So GH+FG should = FH which it does.

From this we can calculate the distance between the pivots & points of the outside arms of the calipers, AF & AH where they are each equal to twice the length of FG plus the length of GH or more simply FH+FG

So AF&AH=FH+FG, =200+123.6=323.6mm

So AF&AH=323.6mm, the distance between the pivots and points on the outside arms.

Now to the inside arms

The distance between the pivots on the short arm CE is equal to the length of FG which we already know to be 123.6mm

The distance between the pivots on the long arm at BE is also 123.6mm.

All that remains is the distance BG between the pivot & the end point

So BG=FH which we know already to be 200mm in this example.

So now I can decide on the size of the calipers I want to make to fit the project.

**In summary then**

Distance FH you decide

Distance GH=FH/2.61803399 (where 2.61803399 = 1+ the Fibonacci golden ratio)

Distance outside arms = (2xFG)+GH

Distance of Short Arm CE=FG

Distance between longer inside arm pivots BE =FG

Distance longer inside arm BG=FH (the length you decided in the first place)

**There is a quick and easy way to do it fairly closely in you head, surely not you say.LOL**

In the above example take 200 as one dimension of your project

If you multiply by 0.6 and 0.4 you get very close to the **Golden Ratio**

EG: Length 200m, Height 200×0.6=120mm, Depth 200×0.4=80mm

Using the exact ‘Golden Ratio’ I would have come up with
Length 200m, Height 200×0.6=123.6mm, Depth 200×0.4=76.4mm

There is not much in it at all and it is easy to remember. Like Kilometers to miles just multiply by 0.6 & you have a rough answer

Now all I have to do is go and make my Fibonacci Gauge.

If anyone finds a problem with the logic please let me know ASAP

-- Grumpy - "Always look on the bright side of life"- Monty Python

## 11 comments so far

degoose

home | projects | blog

7259 posts in 3888 days

#1 posted 08-06-2011 05:09 AM

Well done mate… and don’t be so grumpy…Even I can work that one out…I might even make one… I usually do things by eye…

-- Don't drink and use power tools @ lasercreationsbylarry.com.au

Grumpy

home | projects | blog

25767 posts in 4385 days

#2 posted 08-06-2011 05:15 AM

Who said I’m Grumpy?. LOL

Thanks mate, another jig around the shop won’t go astray.

-- Grumpy - "Always look on the bright side of life"- Monty Python

Karson

home | projects | blog

35207 posts in 4934 days

#3 posted 08-06-2011 05:49 AM

Great Grumpy. And if you make them out of 2X4’s they are easy to find. Until you cut them up into smaller pieces for some project.

-- I've been blessed with a father who liked to tinker in wood, and a wife who lets me tinker in wood. Appomattox Virginia [email protected] †

Grumpy

home | projects | blog

25767 posts in 4385 days

#4 posted 08-06-2011 11:08 AM

The sky is the limit

-- Grumpy - "Always look on the bright side of life"- Monty Python

Lee A. Jesberger

home | projects | blog

6866 posts in 4513 days

#5 posted 08-06-2011 12:57 PM

Very well written, Grumpy. You do realize however, if everybody starts using gauges to determine the proportions of their furniture, there will be less firewood in the world.

Liable to throw off the delicate balance of something!

Lee

-- by Lee A. Jesberger http://www.prowoodworkingtips.com http://www.ezee-feed.com

Jim Jakosh

home | projects | blog

23507 posts in 3639 days

#6 posted 08-06-2011 10:03 PM

Well done,Grumpy!!

-- Jim Jakosh.....Practical Wood Products...........Learn something new every day!! Variety is the Spice of Life!!

Grumpy

home | projects | blog

25767 posts in 4385 days

#7 posted 08-07-2011 12:17 AM

Thanks Jim

Lee, don’t mention that dirty word firewood, LOL. Any save from the ashes is a good save.

-- Grumpy - "Always look on the bright side of life"- Monty Python

Dennisgrosen

home | projects | blog

10880 posts in 3649 days

#8 posted 08-07-2011 09:09 AM

thank´s Grumpy nice work :-)

bookmarked for future use

take care

Dennis

jimp

home | projects | blog

208 posts in 4295 days

#9 posted 08-07-2011 07:48 PM

Thanks for putting this together!!

-- - Jim, Carroll, OH

Roger

home | projects | blog

21013 posts in 3338 days

#10 posted 08-08-2011 03:51 AM

ditto, what everyone else said. got it in the favs

-- Roger from KY. Work/Play/Travel Safe. Keep your dust collector fed. [email protected]

dannyfixit

home | projects | blog

17 posts in 3169 days

#11 posted 08-08-2011 04:06 AM

Great work!! Now I have to go take a couple Excedrin!

-- - Follow your passion...

## Have your say...