How to Use a Universal Bevel Protractor

Tape the floor plans you are going to be measuring, or a blank sheet of drafting paper if you are creating a new drawing, to the drafting table. Use small strips of masking tape on each corner of the paper. Make sure the sheet is flat on the table.

Place the drafting arm with the universal bevel protractor attachment on it over the sheet of paper and pull out the center knob of the protractor attachment to allow the protractor tool to swivel around.

Align the straight edge on the protractor to one of the lines on the floor plan, or to one of the edges of the blank drafting paper sheet if you are making a new drawing. Push in the center knob to lock in the protractor once you've aligned the straight edge. Write down the reading on the protractor if you are simply measuring angles.

Place the straight edge of the protractor on the location on the sheet you want to draw a line and draw that line by pulling a pencil lightly along the edge of the straight edge of the protractor. If you are not making a new drawing, skip this step.

Pull out the center knob of the protractor and align the straight edge to the second line of the angle you are measuring, or to the angle you want to make if you are creating a new drawing. Push in the center knob to lock the protractor and write down the measurement if you are simply measuring an angle.

Calculate the measurement between the two lines in order to come up with the angle. For example, if you the fist line was on the zero, and the second angle was at the 45 degree line then your angle is a 45 degree angle. If your first line was at the 1 degree line, and the second angle was at the 91 degree line, then your angle is a 90 degree angle, and so on. If you are creating a new line, then draw that line in the same manner that the first line was drawn.