Suka2

Different types of geometric development for Claw / Barbe / Klaue / Lip Angles. Keywords Flächenschiftung Lotschiftung Klauenschiftung Kehlklauenschifter Gratklauenschifter  Shiftung Shiften Klaue Barbe Beard German method of drawing out the claw for the jack rafter at the valley. Only works on equal pitched roofs. French method of drawing out the purlin rafter claw. Works on unequal pitched roofs. Another example of developing the claw angle on the purlin rafter. The rafter claw is developed from the intersection of 3 planes. The plane on the bottom of the hip rafter. The plane on the bottom of the rafters. The Roof Surface Plane. The intersection of the roof surface plane and the bottom of the hip rafter plane develop a line of intersection that is parallel to the hip rafter. The intersection of the plane on the bottom of the rafters and the plane on the bottom of the hip rafter develop a line of intersection that is parallel to the hip rafter. The next 3 drawings are for the jack ra

Sloping Ridge Dormer drawn out using dever de pas for the jack rafter perpendicular to the roof surface. After I developed the geometric drawing I realized I had done a great job developing the trigonometry for devers de pas for my Rafter Tools apps, but never developed the geometry to actually draw out the  rafter. Time to open up Louis Mazerolle's book, Traite Theorique Et Pratique De Charpente again.

Update: 2-28-14 This blog article is still valid, but see Tréteaux Roof Framing Kernel and Claw Lines   and the  Tréteaux Angles Check  for more information on Hip Rafters rotated into the roof surface. _____________________________________________________________________________ Will Beemer, at the Heartwood Timber Framing school in Washington Massachusetts was going to post this at JLC in the Devers De Pas thread, but couldn't login to the JLC forum. http://www.heartwoodschool.com/ Anyway, the reason that traditional European carpenters rotated the hip rafter was so that they didn't have to cut a backing angle, I assume. Doing this without power tools would be a burden. In modern work I think they mostly use plumb sided members, like us. But they still need to know the old way since so much of their work is restoration. This peaked my interest in the rotated hip rafters, especially the rotated hip rafter with jack rafters that have a 90° miter angle. This is kinda like an oxy

More theories on the sloping ridge dormers. The sloping ridge on the dormer is actually a hip rafter, so I developed the ground plan for the hip rafter and then used the standard folding roof surface development. With the folding roof surface it's easier to develop the lines for the jack rafter miter and bevel angles, as well as the claw lines. Sloping Ridge Dormer Ground Plan with the hip rafter plan angle, profile rafter slope angle and the hip rafter slope angle. Once you establish the hip rafter run line based on the slope of the sloping ridge you can draw the Eave Line / Ground Line / Gutter Line / Sewer Line / Égout / Hauptdachtraufe / Main Roof Eaves /Trauflinie / Eaves. The profile rafter run is always perpendicular to the Eave Line. You can use the rafter length of the profile rafter to establish the real roof surface of the dormer. In this drawing I'm checking the geometric roof surface development on the real roof surface of the sloping ridge dormer. Perspective view

Still haven't developed the jack rafter perpendicular to the roof surface, but these drawings are a start in the right direction. They develop the sloping dormer profile slope angle. Keywords to search with in German Schifter und Wechsel, im rechten Winkel zur Dachfläche. gauben profil kehlbohenschifter Ground Plan for the Kehlbohenschifter (Valley Jack Rafter) Ground Plan, Elevation and GaubenProfil (Dormer Profile) for the Kehlbohenschifter  Another way of developing the sloping ridge dormer profile slope angle. The sloping ridge is technically a hip rafter, so we can develop the dihedral angle triangle, the angle between the two planes. This gives us the sloping ridge backing angle.