Knockout punch

A knockout punch, also known as a chassis punch, panel punch, Greenlee punch, or a Q-max, is a hand tool used to punch a hole through sheet metal. It is a very simple tool that consists of a punch, die, and screw. There are three different drive systems: manual, ratchet, and hydraulic.

Operation

First a pilot hole is drilled slightly larger than the screw of the knockout punch. Then the die is placed on the screw and the screw is inserted into the pilot hole. The screw is then threaded into the punch and the screw tightened until the punch is drawn completely through the sheet metal.

The manual system uses a screw that has a standard hex head or square head and is driven using an allen key or wrench. A manual knockout punch can handle holes from 0.5 to 1.25 in (13 to 32 mm). The ratchet system has a custom ratcheting wrench that uses a ball screw to make the process faster and easier. This type of system has a mechanical advantage of approximately 220:1 and can punch holes up to 3 in (76 mm) in diameter in 10 gauge mild steel. A hydraulic system is much bulkier and heavier than the other systems but it is the easiest to use and can make holes up to 6 in (150 mm) in diameter. It is a two piece system where the dies are attached to the ram which is connected to the hydraulic unit via a flexible hose.

Q-Max

Q-Max is a type of ship, specifically a membrane type liquefied natural gas carrier. In the name Q-Max, "Q" stands for Qatar and "Max" for the maximum size of ship able to dock at the LNG terminals in Qatar. Ships of this type are the largest LNG carriers in the world.

Technical description

A ship of Q-Max size is 345 metres (1,132 ft) long and measures 53.8 metres (177 ft) wide and 34.7 metres (114 ft) high, with a draft of approximately 12 metres (39 ft).

It has an LNG capacity of 266,000 cubic metres (9,400,000 cu ft), equal to 161,994,000 cubic metres (5.7208×10⁹ cu ft) of natural gas. It is propelled by two slow speed diesel engines, which are claimed to be more efficient and environmentally friendly than traditional steam turbines.

Q-Max vessels are equipped with an on-board re-liquefaction system to handle the boil-off gas, liquefy it and return the LNG to the cargo tanks. The on-board re-liquefaction system allows a reduction of LNG losses, which produces economic and environmental benefits.