Saturday, March 21, 2020

A Barn and its Daisy Wheel



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Not a very neat daisy wheel is it?



About 8" across, it was found during the dismantling of an upstate NY barn, c. 1790, scribed onto a board used to sheath the roof. The lines were drawn with a divider, not a marker. They can be seen in a raking light.The board is still in its proper place. This is a tracing made of the pattern carved by the pin of the divider.




The barn is probably the first of 4 connecting barns, c.1790. Green Mountain Timber Frames recently dismantled, repaired, and sold this barn for reuse.






It has modified gunstock posts, a 5 sided ridge pole, rafters spaced 38" on center.












The daisy wheel determined the framing layout.

The petals are the arcs of the radii. The points of the petals divide the circumference and locate the diameter. The sheathing board with the daisy wheel was a template, the reference for lengths and relationships. When it was no longer needed it became sheathing.

The master carpenter could rotate the daisy wheel first with one diameter  vertical and then with one diameter horizontal. He could use all 12 points and spokes. The radius and the distance between each point are the same length.



So how did the carpenter begin? He and the farmer knew the approximate size and location of the proposed barn. He decided on a width (the radius of his circle) and drew his daisy wheel.

Using the points on the circumference and a line, he marked the width and the rectangle of the circle  ( the 'x') - The green dashed lines show how he determined the length of the barn. The dashed red lines show the floor plan . 





The farmer wanted an English barn with a center door. The door needed to be a certain width for easy movement. 
Was 32' long enough? Would a 12' wide door give him enough working space on either side of the door? Would a 12' high wall work?  If that 12' were also the height of the barn wall there would be enough space for a lintel at the top of the door frame for strength. And what size are his timbers? 




He decided 11'-2" was wide enough, 12'-4" tall enough. The
carpenter laid out the door within the circle.
The width of the door is the radius of the circle, and the height of the barn wall.
The square laid out by the arcs of the radius.







The placement of the door lintel is set at the crossing of the arcs of the radius.




Since the door is in the center of the wall, the right side mirrors the left.  The arcs  - dashed red line -  locate the center of the circle to the right. 
The right side could also have been stepped off with a large compass.


 


The interior bents of the barn fit neatly into the daisy wheel geometry. The rectangle is laid out by the division of the circumference into 6 equal parts. The dashed red line shows the rectangle of the daisy wheel. While the layout of the barn is a traditional English pattern, dropped beams are the regional Anglo-Dutch vernacular tradition. They are placed using the same geometry as the lintel.






The end elevations fit into the daisy wheel too. Of course! interior and end bents need to be the same size. The plates are not dropped.

This is the first pattern I saw when I began to study how this daisy wheel was used in this barn. I thought the layout began here.
I now think he began, not with this simple end bent, but with the door.



The gable's ridge is 22' high.  22' is also the width of the bent, the side of the square which enclosed the gable end.

The roof pitch was determined by a square using the width of the barn as the dimension.
A carpenter used a framing floor to lay out his bents, mark his mortises and tenons.  This bent could have been laid out on the dirt floor of this barn using twine the width of the barn.   



The daisy wheel was the design for the barn. The carpenter knew how to use it.
The specific 8" daisy wheel probably was the dimension - measured across the diameter - used to locate the holes for the peg: they are all at 32" 4 lengths of the daisy wheel diameter.  The distance between holes for pegs on the braces appears to be 48", 6 lengths. 
Today I have no way to check this. I hope I do in the future.


3/21/2020: This post is a complete revision of a post I first wrote in 2014. 










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Friday, March 6, 2020

Railroad Warehouse Frame c. 1850, Richmond, VT


I first wrote this post in March, 2014. I have now updated it.

This is the model of the post and beam warehouse frame that Mark Goyette wanted to use as the frame for his new house.

Mark's model is not as tall as the original warehouse. He decided to lower the structure so that the ceilings for his house would be 9 ft. high instead of the original 13.

The warehouse was built along side the railroad in Richmond, VT, in the 1850's. It is square rule framed.
By 1850 the need for consistent dimensions in industrial applications had become obvious. Many different individuals owned the various railroads. However, engines, carriages and box cars needed to transfer smoothly from one set of tracks to another - all the rails needed to be exactly the same width and profile to accommodate the wheels which also needed to be the same dimensions.

I was very interested to find out if this warehouse, built to service a railroad, was framed by geometry or the new idea of standard dimensions. Mark Goyette, who restored old cars professionally, was curious too; he had, after all, built the model in order to understand better what he planned to erect. So, I drew up the section of the warehouse to find out what was there.



Such a simple, elegant design!

The necessary width determines the square which determines the height.
The 3-4-5 triangles determine the roof pitch. 2  3-4-5 rectangles are the box. The location of the cross tie  is set by the intersection of the square's diagonal and the triangle's hypotenuse.
The roof pitch is - in modern terms - a 9/12 pitch.




March 6, 2020 update:
 
The frame is 5 H bents. The bent shape looks like an H because of the  'dropped' plate - see the arrow This is how many barns and houses in southwestern Vermont in the Hudson River watershed were framed, and is a hallmark of Anglo-Dutch framing, 2 framing systems joined.
A Dutch frame would have bents about every 4 feet. An Anglo frame spaced the bents between 15 and 20 ft.  These bays appear to be 12 ft. apart.
A Dutch frame has the bent's plate framed into the post on the side, below the plate that carries the rafters. An English bent has both plates joined to the post at the the top, at the same height. This requires a more complex mortise and tenon joint.

Finding this hybrid frame in an ordinary service building, built by a corporation - not an individual framer who has moved upstate and taken his framing traditions with him  - in northern Vermont in 1850, is surprising and interesting .
   

Thanks to David B. AdolphusTravers for the photograph.

Wednesday, January 8, 2020

Practical Geometry - Drawing a Square with a Compass, Part 2

Here are 4 more ways to draw a square with a compass.


How to draw a square with a compass  #3
Peter Nicholson wrote about Practical Geometry in 1793.  His first plates are introductions to the first rules of geometry: using a compass to bisect a line,

My blog post about him is : https://www.jgrarchitect.com/2016/08/practical-geometry-as-described-by_16.html
It includes images of Plate 2 and Plate 3.

Here I have copied just the image of a square. Nicholson includes instructions for finding the square 'abcd' by dividing the arc a-e (the black spot) in half then adding that half to a-e and b-e find d and c.





Asher Benjamin and Owen Biddle in their pattern books copy Nicholson.
They do change the order of the letters which makes the steps easier to follow: a and b are 2 corners of the square. The arcs of a and b create c. Half of arc a-c is d. Add the length b-c to the arcs of a-c and b-c to find e and f: the square has its 4 corners.




How to draw a square with a compass, #4


A 3/4/5 triangle always has a right angle (90*) where the lengths 3 and 4 meet.
2 3/4/5 triangles are a rectangle which is 3/4 of a square.
I have drawn this on graph paper for clarity.

When carpenter squares became widely available and accurate, the square corners were easy to establish. The compass was only needed to lay out the length.

Before that - before about 1830 - the carpenter could have laid out his square like this:

His length is laid out in 4 units.
He knows approximately where the 2 sides will be. He does not know if his angle is 90*.




Here I have drawn the arc of the length of 4 units - on the right side. Then the arc of 5 units with its center at 3 units  on the left side. where they meet will be the 3/4/5 triangle.











The carpenter did not need to layout the full arcs as I have drawn them.
If he held his Line at the right lengths he could have marked a bit of both arcs where he thought they cross, and then placed a peg where they did cross. He would have checked his square by matching diagonals.


The relationship between the 3/4/5 triangle and the square is good to recognize. However, the 3/4/5 triangle is usually the only geometry. Layout by a carpenter square, widely available in the 1840's, was simpler and took less training than using a compass.





This small, simple house, built c. 1840 for a cobbler, was probably laid out using a carpenter square. I've tried other geometries which almost fit. The 3/4/5 triangle does.


I wrote the original post in 2014. It's time to revisit and review.
Here's the link to the post:
  https://www.jgrarchitect.com/2014/10/the-cobblers-house-c-1840.html



How to draw a square with a compass, #5

 Lay out a perpendicular through a line. Draw a circle with its center where the lines cross.
Draw lines - here dash/dot lines - between the points where the circle crosses the lines.

This square, as a diamond, was often used by finish carpenters because it easily evolves into more complex layouts. 

Below is the entrance porch for Gunston Hall, designed by William Buckland, c. 1761. The rotated squares determine the size of the porch. They also locate the floor, the pediment, the roof pitch, the size of the arch, the height of the rail.
 My post on Gunston Hall is: https://www.jgrarchitect.com/2014/05/gunston-hall-ason-neck-virginia.html








Here the glass facade of
 the Mass. Ave. entrance to MIT. For more, see:











https://www.jgrarchitect.com/2018/04/a-little-bit-of-geometry-of-mit.html



 How to draw a square with a compass, #6

 On a line select a length - see the dots .
Using the length as the radius draw a circle using one dot as the center.
Now there are 3 dots. Draw 3 circles using all 3 dots as centers.
Drop a perpendicular line at the first circle's center.
Now there are 2 new dots for centers of more circles.
Connect the petals where the 4 circles cross.
A square.




This modest farm house, c. 1840, used the square crossed as the squares above are for the Gunston Hall porch.

https://www.jgrarchitect.com/2014/09/how-to-construct-square.html








One last note: the circle to square diagram #6 can also become the diagram for #5. 

Each master builder probably had his preferred way of using his compass, even when he practiced within a tradition.
Still, just as a 3/4/5 triangle is part of a square, these diagrams are also simply different choices, different perceptions of the same geometry.