Wednesday, September 18, 2013

Snow Spitter 2.0, update

Our snow spitter progresses. Pervious episodes have documented the building of this contraption. Most of this work is John's. I have held tools, passed screws, and found tools. Now we get on to the superstructure.
We have added cross-beams and diagonal braces to the basic structure.  More diagonal braces to come. Note the plastic bags at the bottom of each upright.  This is vapor barrier stuff. Next is John's idea. To suppost the ridgepole use plywood. We have a big stash of outdoor plywood, kindly left behind by the previous owner of the house. Or someone. Here we are cutting a big triangle out of plywood. The big triangle will be notched to take the ridge beam, and the triangle (actually two of them) will be screwed on to the cross-beams. Plywood is amazing stuff. It will take enormous loads, because the plies in the plywood go at different angles to the grain. Nothing like free plywood.
Today John got the triangles up and the ridge beam placed. I neglected to take photos of this operation. But the ridge beam is up and running. Well, sitting, really. We very much do not want it to run. We want it to be still. The real purpose of the snow splitter, as I must have said before, is to keep the snow that slides off the roof from blocking out access to the house; save hours of shoveling hard compacted snow. This is impact loading. All the stuff you leaned in the strength of materials courses does not apply. It has to take a very sudden overload for about the one minute it takes the snow to slide off the roof. After that, the static load is trivial.

Anyway it is very pleasing. This is a much better structure than we put up last year, so we live and learn. I will add some more photos as this project progresses.

The birches have started to turn yellow. It is fall. More on that later. As usual our projects  progress JIT (Just In Time). Today it was 3C and that's warm. It got to 0.5C last Sunday. Close to freezing. 34F for metrically-impaired audiences. So it snowed in Fairbanks today. We have a very limited time to complete this project.

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