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Topic: Intersection of two bullnoses
Replies: 4   Last Post: Apr 2, 2009 7:25 PM

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Posts: 70
Registered: 12/6/04
Intersection of two bullnoses
Posted: Mar 30, 2009 5:51 PM
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I have a work related problem I have to fashion an intersection between two bull nosed flashing's from a flat sheet prior to forming. For those that are unsure to what this is it maybe helpful to visualise a cylinder cut in half length ways so as to form a half round shape like a plastic rainwater gutter. Now imagine this being put onto a wall cut side against the wall so as you are seeing the "underside" of the pipe facing you. Now imagine this was to run for the entire length of a wall until it comes to a corner where it is mitred to accept an exactly similar pipe coming around the other corner.
Now that bit is easy and I have fashioned these before using a formula that allows me to plot points on a flat piece of metal the desired shape ( I think its a sine curve ) that I can cut out and when I form it into a half circle shape the end forms a perfect mitre-line for the other similarly worked and shaped piece. I however have trouble working out the shape of the curve when one of the flashing's comes around the corner at an angle such as you would get when a straight elevation meets a gable. So that one runs horizontal but the other comes in at an angle of maybe ten degrees. I have a strong suspicion that the curves are both sine curves like the first but that one might be "offset" as it were by an amount X which will follow the formula:

D*PI/(360/Theta) where D equals diameter and theta is the pitch of the second flashing in relation to the first.
I do hope you smart people can maybe help me out on this many thanks. Steven

Message was edited by: Steven

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