Abstract: A tool and method for cutting a circular opening and retaining the cut portion. The tool comprises a shaft having at least one cutting thread and at least one tapping thread, or at least one cutting thread and at least one male screw thread, or only at least one tapping thread, or only at least one male screw thread, or a cutting tip and at least one tapping thread, or a cutting tip and at least one male screw thread, and a cutting member having at least one cutting bit radially displaced from the shaft. The shaft and the cutting member have a mutual rotational axis. An alternative tool has a spaced distance on the shaft between the cutting member and the at least one cutting thread and at least one tapping thread, or the at least one cutting thread and at least one male screw thread, or the at least one tapping thread, or the at least one male screw thread, or the cutting tip and at least one tapping thread, or the cutting tip and at least one male screw thread.

Abstract: A method of measuring the differential pressure of two fluid pressure sources includes connecting a manometer having a wireless transceiver for transmitting measured pressures to a remote location and connecting a second manometer to a second pressures source. The second manometer then is operable calculate differential pressure value based upon the measured and electromagnetically transmitted fluid pressure value. If two remote manometers are used and are both transmitting their measured fluid pressure values electromagnetically, the second manometer is operable to determine a differential fluid pressure for the two fluid whose pressures were electromagnetically transmitted. An apparatus includes a manometer having a electromagnetic transceiver for transmitting and receiving fluid pressure measurements.