How to Measure with a Plumb Bob
- 1). Place the hook end of a tape measure inside the door header touching the right side jamb of a doorway. The door header is the top board on the inside of a door frame.
- 2). Stretch the tape measure out to the left. Mark a dot on the door header with a carpenter’s pencil 3 inches from the side door jamb.
- 3). Hammer a 4d finishing nail partially into the door header on the dot.
- 4). Wrap the loose end of the plumb bob string around the nail so that the length of the string allows the plumb bob to hover about ¼ inch above the floor.
- 5). Place the tip of a tape measure on the floor under the plumb at the right side door jamb.
- 6). Stretch the measuring tape to the left of the plumb bob and note the exact center of the bottom on the measuring tape. If a doorway is exactly level vertically, the center of the plumb bob will be at the 3-inch mark on the measuring tape.
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