compound angles

[lotechman]

Often when I run into a drawing that calls for a diagonal running down and across a bay I use a graphical method to plot the cuts.
Does anyone have a clear method for doing resultant angles using trig functions and the old calculator? it would be nice to do this for square tubing and wide flange members.

[orphan68]

Got a print or more specifics? I have a book that can be of help. I ccan scan and email you what you need.

Tony

[lotechman]

Got a print or more specifics? Tony
I will copy down the specifics of the latest one at work. It is a diagonal with one end connecting to a beam flange that is tipped off vertical and the other end hits a tube at an angle and requires a vee cut opposite to what I would call a birdsmouth.
A good detailer would have given us a drawing of the tube but we are on our own on the shop floor.

[Brett]

Can you post more info lotechman? (soon to be hitechman:))

Im pretty sure what youre after is called the dihedral angle

[iroc]

The dihedral angle is the angle between two planes. The dihedral angle between planes in a general tetrahedron is closely connected with the face areas by a generalization of the law of cosines.:) :) :)

[lotechman]

This recent one was six inch tubing. In larger shops I have had the benefit of a good detailer. this time people were asking me and I was on other things so here is the rough measurements. The actual unit has a twist! The upper connection was the flange of a WF beam tipped over off the vertical by 11.3 degrees.
Lets do a simple one first :)
I can calculate diagonals using pythagorus twice but the angles start to give me trouble unless I draw it out and make a wraparound.

[Brett]

The dihedral angle is the angle between two planes. The dihedral angle between planes in a general tetrahedron is closely connected with the face areas by a generalization of the law of cosines.:) :) :)

True iroc, but they can also be used to find the angle of intersection of any regular 3 dimentional shape and an inclined plane




This recent one was six inch tubing. In larger shops I have had the benefit of a good detailer. this time people were asking me and I was on other things so here is the rough measurements. The actual unit has a twist! The upper connection was the flange of a WF beam tipped over off the vertical by 11.3 degrees.
Lets do a simple one first :)
I can calculate diagonals using pythagorus twice but the angles start to give me trouble unless I draw it out and make a wraparound.


I see you already know the two offsets ,thats a bit different.(and easier)
One simple way is to
1) divide small dimention by the big dimention
2) then press inverse tan (sometimes tan to the power of -1)

If your using the small small offset and hypotenuse
1) as above
2) use inverse sine

If your using the large small offset and hypotenuse
1) as above
2) use inverse cosine

Is that what your after lotechman?

[lotechman]

Finally I had time to play around and figured it out. Would my development pattern work? I included an outline of my math with the original image