Rafters
Hi Mac,
I'm afraid I almost lost the will to live in that video.
He's using that "building calculator" to avoid doing/explaining a bit of geometry and good old Pythagoras for calculating right-angle triangle sides.
For what it's worth here's my twopenn'orth.
Firstly dealing with the plumb cut where the rafter will meet the ledger board, wall plate or whatever one wishes to call it (and for eventually also for cutting the plumb cut at the bottom). I've mocked up a model here to illustrate the idea of creating a cutting template.
1) Get hold of a square/rectangular piece of card (or thin ply if you want it to be more robust).
Make sure the corners are 90 degrees.
2) For his "rises 7" in 12" then as per pic 1 starting from the lower RH corner mark off along the bottom edge 12"and then mark off 7" up the RHS edge from that bottom corner.
3) Join as pic2 and cut off the resulting triangle and keep the rest.
4) Place this remaining piece of card/board on your rafter as shown in pic 3 and draw along edge I've marked as CD.
There is your plumb cut line for the top as per pic4 (excuse the line thickness pen not cooperating!)
Will continue with the rest in a new reply if you're interested
p { margin-bottom: 0.25cm; line-height: 120% }
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