Using a reciprocating saw to cut an opening into a wall made of plaster and wood lath runs the risk of cracking the plaster around the edges of the hole. To minimize the problem, find the nearest stud outside the desired cut line and screw a length of 2x to it, as shown in the drawing.
Now you can use a reciprocating saw alongside the stud to cut the plaster and lath. The 2x will act as a clamp, preventing the vibration from damaging the plaster you want to save.
Allan R. Aho, Minneapolis, MN
