Pdx 42" update

[Macrinehart]

The rest of the lines for the first brick are drawn relative to the end point of lines 1 & 2. On the top of the brick, use the side angle T-Bevel to mark lines 3 and 4 as shown. These converge to the top inside edge, the narrowest width.



Rotate to the inside face and use the side tilt T-Bevel to mark lines 5 and 6, which diverge.



Finally rotate again and mark lines 7 and 8. These also diverge and should connect to the starting points on lines 1 and 2.

[Macrinehart]

There is room to get 2 dome bricks for each firebrick. To finish marking the second domebrick flip the firebrick and rotate 180 degrees so that that the inside top edge is facing you. Then use the calapers to mark the outside bottom corner on the swcond fire brick.
I label the top and bottom for reference. Notice that the top of the first dome brick is on the same face as the bottom of the second brick.

Next we mark lines 9 - 12. Keep in mind the rule of no parallel lines, lines 9 - 12 will converge and then diverg from the center line. When your finished the origin of line 9 connects to the end of line 12.

[Macrinehart]

Once I finish marking all the guide lines on a course of bricks, it's time to start cutting. Using the HF wet saw with tilt blade makes this task a lot easier. I start by setting the blade tilt using a magnetic angle finder. The angle should match the side tile angle. Perfection is not required. I'm content to get within a 1/10th of a degree.

Once I have the angle set, three cuts yields 2 bricks. I line up the line with blade and cut. Do the two outside cuts first, then the middle cut. The only additional consideration is that I clean the cutting bed after each cut because the debris can destablize the bricks.



And for those wierd angles, I just prop the brick I'm cutting with wedges from remains of other cuts found in my boneyard discards, as shown below.