# segmented lay outs w/ tearles geometry...



## Stick486 (Jan 4, 2013)




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## Ghidrah (Oct 21, 2008)

Tearles geometry, I've been using it for over 30 yrs side walling and roofing and didn't know it had a name. 1983 or 84 When "This Old House" was hosted by Bob Villa and Norm Abrams, they had a little sort of contest. Send in a suggestion and they'll send you a T-shirt or ball cap if they use the suggestion on TV. 

I sent in 2 one was to use Andersen step flashing to set windows by yourself the 2nd was to find the correct spacing for shingle courses without math from starter course to window bottom then top then frieze. The man in the video uses the same technique for evenly segmenting a line or spaces between lines.

If they ever used my suggestions I never saw but I did get a t shirt from the show.


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## tomp913 (Mar 7, 2014)

I remember this from high school geometry. I used this to make a fixture for setting my track saw for cross-cuts; there is a base that attaches to the track and which can actually be set to any angle. I took a piece of birch plywood and a strip of poplar and clamped them to a table as shown in the first photo. Marked a line parallel to the edge of the poplar and struck two arcs with a trammel around the starting point that I picked. From the intersections, using a larger radius, drew two more arcs intersecting at the top of the plywood panel. The line from the starting point to the intersection is perpendicular to the original starting line/edge of the poplar/edge of the plywood. An aluminum strip screwed along the line is then used as a fixture to set the track perpendicular to the base, giving dead square corners when the material is cross-cut.

Tom


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## Garyk (Dec 29, 2011)

I've been doing it the hard way (math, I do cheat a bit, I have a construction calculator).

Thanks Stick you did good.........


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## Knothead47 (Feb 10, 2010)

My son is a mechanical engineer with a double major in engineering and math. His wife was a math major in college and taught math and physics in high school. Help is a phone call away. BTW, never heard of the term for this part of geometry.


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## Ghidrah (Oct 21, 2008)

Doing the math isn't the issue, marking the project is. How does one accurately mark 4 71/128ths or 4. 5546875 in multiples consistently and why would you? It's simpler to pick a number like 5" TTW for side walling then diagonal your tape from point a to b and mark 5s. The average homeowner can't see it, (a blur to their eyes) but a trained pro can see a 1/4" difference in a course height change. 1/16ths and 1/8ths, as long as the changes are maintained around a house are invisible to everything but a tape measure or transit.


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