## Monday, July 27, 2015

### Learning from a Workshop

The IPN Workshops at the Shelburne Farms Coach Barn were superb.
The barn is magnificent. To be able to be in and around it for 4 days was true luxury.

Above left is the main entrance from the court yard. Right is the dormer for the hay loft door above the stable. Below is half of one barn door showing its hinges and brick work.

The food was plentiful and excellent - local and fresh.
The company and the workshops couldn't be beat.
Of course I plan to go to the 20th annual IPT Workshop to be held in Virginia, autumn of 2016 . www.ptn.org

My presentation was almost derailed by the cheap school compasses I brought. The compasses did not hold their angle, so the diagrams we drew weren't true. I had not anticipated that the participants might not know how to draft: they needed basic instructions and better tools.

Luckily people bore with me and I presented twice. Many people talked with me about geometry between sessions.

Here is what worked best:

The daisy wheel: As people found the rectangle created by 4 points  they easily understood the geometry of the Old First Church in Bennington.

Making a square:  beginning with a line and a circle.

The hardest part for people to figure out was how to draw the arcs for the vertical line. I felt very successful when I heard one person explaining how to do it to another.

The 1830's farmer's cottage pleased everyone. They could see how to use what they had drawn.

A few people were able to rotate the square 45* to complete the diagram as shown

I brought the pictures from my post on  Asher Benjamin, Owen Biddle and Peter Nicholson. http://www.jgrarchitect.com/2015/07/geometry-of-cobb-hepburn-house-part-2.html

We were to draw squares based on their diagrams  - as shown here:
This is where, especially, the compasses were not up to the task. The squares were not true;they were cock-eyed. I loaned my good compass out - so much easier to draw with good tools!
So, I explained and demonstrated. People practiced.
The pattern books' first pages of geometry turned out to be an adventure.

I thought to show 4 different ways to grow a layout from one dimension.
Instead I used the different buildings and diagrams as illustrations as people asked questions,
Good, thoughtful questions.

What a good time we had!

## Saturday, July 11, 2015

### ME: giving a IPTN Workshop, July 22 - 24!

July 22-24, 2015 in the Shelburne Farms Coach Barn, Burlington, Vermont

http://www.iptw.org/iptw_2015_home.htm

My workshop is called

"Line, Point, String: Scribe"

I want everyone to draw. So there will be

24 school compasses
2 packs of unlined paper
1 pack of grid paper
a pencil sharpener
some straight edges - not the "thin ivory scale or box rule" recommended by Owen Biddle
erasers - although I want people to explore, not correct mistakes

And of course, photographs and drawings, some posters.

I hope to help people be comfortable with geometry, to be able manipulate the forms,  design their own frames -
and thus create buildings whose parts are proportional to each other. Or maybe just understand how people did once upon a time.

Running  a power point presentation on geometry and construction may be possible.

I hope to be able to schedule a working session for all of us who are exploring geometry.
We have met at other conferences by chance. Maybe this time we can share together what we know.

If you are there too please come find me and introduce yourself.

## Friday, July 10, 2015

### Geometry of the Cobb-Hepburn House, an aside for skeptics

http://www.jgrarchitect.com/2015/02/baring-bones-of-house.html
http://www.jgrarchitect.com/2015/06/the-cobb-hepburn-house-frame-tinmouth-vt.html
http://www.jgrarchitect.com/2015/06/geometry-for-cobb-hepburn-house-part-1.html

Here is the basic geometric shape used for the Cobb-Hepburn House.

When the house was built in 1780, the town of Tinmouth was less than 10 years old. It was the frontier. Paper would have been precious, not generally available for drawing house plans.

The master framer probably used dividers to layout the frame. We can see that he used them to draw the 2'  off set marks on the posts. Look to the bottom right of the post - 2 half circles above a line.

Sheathing was commonly used for diagrams.
I describe one such board found in a barn here:  http://www.jgrarchitect.com/2015/01/a-barn-and-its-daisy-wheel.html

Click the pictures to enlarge them.

25 years later when paper mills had become common, pattern books were popular teaching tools - beginning with basic geometry.

Here is Owen Biddle's Plate I in  Biddle's Young Carpenter's Assistant, 1804:

A and B are illustrations of how to attach paper to a board. C is the T Square.
(E,F,G are diagrams for perpendicular lines and right angles.  J is a 3/4/5 right triangle.K is the circle defined by 3 points not on a straight line.)

Just under the T Square is
H -  the layout of a square using the length of one side.

Biddle describes these engravings as " some of the most useful geometric problems which every carpenter ought to be acquainted with."
He explains that a student should have "a bow-pen or compass".

Asher Benjamin's  The American Builder's Companion, 1806, Plate II

has similar diagrams on basic geometry for carpenters.

All figures are explained on the accompanying page.
Fig.  12  is the same diagram as Owen Biddle's  H.

Benjamin writes in his Preface to the Third Edition:
"I have first laid down and explained such problems in Geometry, as are absolutely necessary to the well understanding of the subject."
He begins with

Plate I.
Practical Geometry.
Definitions.

GEOMETRY, is that Science which treats the descriptions and proportions of magnitudes in general.

Peter Nicholson's Guide, first published in 1792, in England, begins with geometry. It was updated and reprinted many times in London, New York and Philadelphia.
In his Preface  Asher Benjamin writes that he is "indebted to P. Nicholson's excellent books".

Figure 2 matches Benjamin's Fig.12 and Biddle's H.

This a a print of the actual page, Plate 3 - wear, age spots, and water stains included - in the 10th Edition, 1830.

I have the book in my library - on a long term loan.

.

I  have written this post because of the skepticism I encounter from academics as well as craftsmen.
The use of geometry in construction is often viewed as somehow made up. I suggest doubters read what the master carpenters themselves wrote.

Owen Biddle, Biddle's Young Carpenter's Assistant, originally published 1805, by Benjamin Johnson, Philadephia. Dover (2006) unabridged republication, Dover Publicatons, Inc., Mineola, NY

Asher Benjamin, The American Builder's Companion, first edition published 1806, This print taken from the 6th Edition, 1827; unabridged republication by Dover Publications, Inc., 1969.

Peter Nicholson, The Carpenter's New Guide: Being a Complete Book of Lines for Carpentry and Joinery, Treating Fully on Practical Geometry... 10th edition, John Griggs, Philadelphia, 1830.