If you’ve ever had to make accurate horizontal cuts in old lath-and-plaster walls, you know how difficult the task can be. Both the position of the saw and the flying plaster dust tend to obscure the chalkline or pencil mark. My solution is to mark a second line above the line I want to cut and follow the second line with the edge of my saw’s baseplate. For my saw, the top line ends up 1-1/2 in. above the cutline. That dimension is equal to the distance from the edge of my saw’s baseplate to the blade.
Geoff Ireland, Winnipeg, None