In metalworking, a knockout punch, also known as a chassis punch, panel punch, Greenlee punch, or a Q-max, [1] 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. [2]
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. [2]
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. [3] 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. [4] [5] [6]
There are several sizing systems for these punches. The two most common are those sized for standard electrical knockout sizes and those that are for true dimensional holes. A 3/4 inch conduit size punch actually punches a hole that is approximately 1.1 inches diameter for 3/4 nominal size conduit. A dimensional size punch makes a hole very close to the indicated size. Punch sets are available on both imperial and metric sizes.
Chassis punches are available in a number of shapes, round being the most common. Other shapes include square, hexagonal, and special shapes for thing such as holes with key tabs and D-sub connectors [7] Special shapes often use bolts that are square or keyed and a separate nut on the punch end to ensure alignment of the punch and die.
A screwdriver is a tool, manual or powered, used for turning screws.
Taps and dies are tools used to create screw threads, which is called threading. Many are cutting tools; others are forming tools. A tap is used to cut or form the female portion of the mating pair. A die is used to cut or form the male portion of the mating pair. The process of cutting or forming threads using a tap is called tapping, whereas the process using a die is called threading.
A grommet is a ring or edge strip inserted into a hole through thin material, typically a sheet of textile fabric, sheet metal or composite of carbon fiber, wood or honeycomb. Grommets are generally flared or collared on each side to keep them in place, and are often made of metal, plastic, or rubber. They may be used to prevent tearing or abrasion of the pierced material or protection from abrasion of the insulation on the wire, cable, line being routed through the penetration, and to cover sharp edges of the piercing, or all of the above.
A drill bit is a cutting tool used in a drill to remove material to create holes, almost always of circular cross-section. Drill bits come in many sizes and shapes and can create different kinds of holes in many different materials. In order to create holes drill bits are usually attached to a drill, which powers them to cut through the workpiece, typically by rotation. The drill will grasp the upper end of a bit called the shank in the chuck.
A rivet is a permanent mechanical fastener. Before being installed, a rivet consists of a smooth cylindrical shaft with a head on one end. The end opposite the head is called the tail. On installation, the deformed end is called the shop head or buck-tail.
A forming press, commonly shortened to press, is a machine tool that changes the shape of a work-piece by the application of pressure. The operator of a forming press is known as a press-tool setter, often shortened to tool-setter.
A hole punch, also known as hole puncher, or paper puncher, is an office tool that is used to create holes in sheets of paper, often for the purpose of collecting the sheets in a binder or folder. A hole punch can also refer to similar tools for other materials, such as leather, cloth, or sheets of plastic or metal.
A reamer is a type of rotary cutting tool used in metalworking. Precision reamers are designed to enlarge the size of a previously formed hole by a small amount but with a high degree of accuracy to leave smooth sides. There are also non-precision reamers which are used for more basic enlargement of holes or for removing burrs. The process of enlarging the hole is called reaming. There are many different types of reamer and they may be designed for use as a hand tool or in a machine tool, such as a milling machine or drill press.
A socket wrench is a type of spanner that uses a closed socket format, rather than a typical open wrench/spanner to turn a fastener, typically in the form of a nut or bolt.
Sheet metal is metal formed into thin, flat pieces, usually by an industrial process.
A punch press is a type of machine press used to cut holes in material. It can be small and manually operated and hold one simple die set, or be very large, CNC operated, with a multi-station turret and hold a much larger and complex die set.
Punching is a forming process that uses a punch press to force a tool, called a punch, through the workpiece to create a hole via shearing. Punching is applicable to a wide variety of materials that come in sheet form, including sheet metal, paper, vulcanized fibre and some forms of plastic sheet. The punch often passes through the work into a die. A scrap slug from the hole is deposited into the die in the process. Depending on the material being punched this slug may be recycled and reused or discarded.
An impact wrench is a socket wrench power tool designed to deliver high torque output with minimal exertion by the user, by storing energy in a rotating mass, then delivering it suddenly to the output shaft. It was invented by Robert H. Pott of Evansville, Indiana.
Lineman's pliers, Kleins, linesman pliers, side cutting linesman pliers and combination pliers are a type of pliers used by lineworkers, electricians, and other tradespeople primarily for gripping, twisting, bending and cutting wire, cable, and small metalwork components. They owe their effectiveness to their plier design, which multiplies force through leverage.
Greenlee is an American industrial and electrical tool company headquartered in Rockford, Illinois. It was founded in 1862 by twin brothers Robert L. and Ralph S. Greenlee to manufacture their invention called a hollow chisel mortiser, consisting of a drill surrounded by four chisel blades used in making mortises for mortise and tenon joints, for the furniture industry in Rockford. While no longer produced by Greenlee, hollow chisel mortisers are still used in cabinetmaking today from a variety of other manufacturer. The brothers later diversified into a variety of hand woodworking tools as well as machinery for making wooden barrels.
A screw is an externally helical threaded fastener capable of being tightened or released by a twisting force (torque) to the head. The most common uses of screws are to hold objects together and there are many forms for a variety of materials. Screws might be inserted into holes in assembled parts or a screw may form its own thread. The difference between a screw and a bolt is that the latter is designed to be tightened or released by torquing a nut.
Strut channel, often referred to colloquially by one of several manufacturer trade names, is a standardized formed structural system used in the construction and electrical industries for light structural support, often for supporting wiring, plumbing, or mechanical components such as air conditioning or ventilation systems.
Press tools are commonly used in hydraulic, pneumatic, and mechanical presses to produce the sheet metal components in large volumes. Generally press tools are categorized by the types of operation performed using the tool, such as blanking, piercing, bending, forming, forging, trimming etc. The press tool will also be specified as a blanking tool, piercing tool, bending tool etc.
A hex key is a simple driver for bolts or screws that have heads with internal hexagonal recesses (sockets).
