Bolt tensioners are devices designed to apply a specific tension to a bolt. The device may be either removed once the actual nut is threaded into place, or left in place, in the case of a hydraulic nut.
The metric system does away with all of the different units of volume used in the English system, and instead, uses only one unit to measure volume. That unit is called the liter. Materials Needed: Meter stick or metric ruler; stiff cardboard such as poster board; scissors or hobby knife; tape.
A tiltmeter, is a type of instrument used to detect any kind of tilt in the structure to which it is attached. Most tiltmeters use an air bubble in a liquid-filled tube, much like a typical carpenter's level, but are equipped with sensitive electronics that can detect even the tiniest change in tilt. They either sound an alarm or transmit the data to a remote monitor or other device.