How to Change a Drawn Line to a Cutting Machine

An old carpenter's saying advises, "Measure twice; cut once." If you find that your first measurement is drawn incorrectly, you do not have to redraw it in order to change it. You can use a tried-and-true carpenter's method to make a new line so your cutting machine can follow it. If you know that your first line is straight, you can use it to make your second line and cut the wood accurately according to your new measurements.

Pencil
Tape Measure
Chalk-line tool
C-clamps
Straight piece of aluminum door framing
Straight piece of 2-by-4-inch lumber

Instructions

- 1
  Measure how far off your first line is. For example, you may have drawn it one-quarter-inch too far to the left on your board. Do not erase or redraw it. At one end of the board, measure to the right quarter inch and make a pencil mark. Repeat this process at the other end of the board. Use a chalk-line tool to make your new line. Hook the chalk-line tool's "L" hook over the end of the board and line up your chalk line with the pencil mark you made. Pull the chalk-line tool's gearbox to the other end of the board, allowing the line to feed out. Hold the end of the chalk line on the second pencil mark with your thumb nail. Keep the line taut. With your other hand, pull the line straight up and let it go. The line will snap downward and make a straight chalk line exactly parallel to your drawn line.
- 2
  Measure the distance from the cutting blade on your machine, such as a hand-held circular saw or jigsaw, to the edge of its baseplate. This is the amount of clearance your saw needs between your new chalk line and the guide you will make.
- 3
  Make a new chalk line parallel to your first chalk line. The new line should be exactly the distance required by your saw's baseplate. Measure the distance you need to allow for the baseplate and make two pencil marks at each end of the board. Snap your chalk line and you will have made a straight chalk mark down the length of the board that shows where your saw's baseplate edge ends. This is your line for the guide.
- 4
  Clamp a straight piece of aluminum door framing or a straight 2-by-4-inch piece of lumber so that the edge lines up with the second chalk line you made. Use C-clamps to do this. This is your guide for cutting a straight line. The saw's baseplate will butt up against your guide as you cut.
- 5
  Cut slowly, pressing your saw's baseplate against the guide. Check frequently to make sure that your clamps are not slipping and allowing your guide to move. Concentrate on your guide, but check to make sure the blade is cutting on the first chalk line you made. If you have placed the guide properly and it does not move, your saw will cut exactly where you want it to.

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