Die grinder
Encyclopedia
A die grinder is a handheld power tool
used to grind
, sand, hone
, polish
, or machine
material, typically metal but also plastic or wood. They are usually pneumatically driven, although versions with electric and flexible shaft
drive also exist. Their name comes from one of their earliest and archetypal applications, tool and die work
, where they are used to create the precise contours of dies
or molds
. Especially before the advent of widespread CNC
usage, they were heavily relied upon for contouring via manual skill comparable to a sculptor's
. CNC now provides much of the contouring for die and mold interior surfaces, but die grinders are still very useful for hundreds of cutting needs, from sculpture-like contouring in the absence of CNC, to cut-off of bar stock
, to any of the cutting and grinding needs of fabrication
, such as in the work of welders, boilermakers, millwrights, ironworkers (steel erectors), sheet metal workers (such as auto body workers
and HVAC
technicians), to woodworking
(especially cabinet making
), hacking, and other hobby or business pursuits. Die grinders are often used for engraving
, cylinder head porting
, and general shaping of a part.
Die grinders are very similar to rotary tool
s, and in fact some people do not make any distinction between them. The difference between a die grinder and a rotary tool is mainly one of mental classification rather than etic traits. Die grinders are thought of as industrial tools, whereas rotary tools are thought of as tools for the residential mass-consumer end-user. There is overlap, though, as many consumers own die grinders, and many industrial users have rotary tools. The distinction is not very significant. Die grinders may feature heavier construction (such as being made of die-cast metal
rather than molded plastic) and higher top speeds for the spindle
(some can exceed 30,000 RPM
unloaded). All modern examples of what people call rotary tools have plastic bodies.
, which is a convenient means of chucking
in this application and provides the concentricity needed for high-RPM use. It also allows for quick changes in cutters. In some applications, other quick-change indexable
chucking systems can be used, similar to the indexable chucking types now commonly found on consumer pistol-grip drill
s.
Other common PPE
in die grinder use includes:
used on many handgun
s.
Tools with electric motors often have electrical safety features such as grounded cases (wired to a grounding conductor, which uses the grounding prong on a plug) or double insulation. Some may have both, but more often not, because regulatory requirement
s require only one or the other.
Power tool
A power tool is a tool that is actuated by an additional power source and mechanism other than the solely manual labour used with hand tools. The most common types of power tools use electric motors. Internal combustion engines and compressed air are also commonly used...
used to grind
Grinding (abrasive cutting)
Grinding is an abrasive machining process that uses a grinding wheel as the cutting tool.A wide variety of machines are used for grinding:* Hand-cranked knife-sharpening stones * Handheld power tools such as angle grinders and die grinders...
, sand, hone
Honing
Honing may refer to:* Honing , machining a surface by scrubbing an abrasive stone against it* Sharpening edged tools with a manual hone* Henkjan Honing , Dutch musician* Honing, Norfolk, English village* Playing Heroes of Newerth...
, polish
Polishing
Polishing is the process of creating a smooth and shiny surface by rubbing it or using a chemical action, leaving a surface with a significant specular reflection In some materials polishing is also able to reduce diffuse reflection to...
, or machine
Machining
Conventional machining is a form of subtractive manufacturing, in which a collection of material-working processes utilizing power-driven machine tools, such as saws, lathes, milling machines, and drill presses, are used with a sharp cutting tool to physical remove material to achieve a desired...
material, typically metal but also plastic or wood. They are usually pneumatically driven, although versions with electric and flexible shaft
Flexible shaft
A flexible shaft is a device for transmitting rotary motion between two objects which are not fixed relative to one another. It consists of a rotating wire rope or coil which is flexible but has some torsional stiffness. It may or may not have a covering, which also bends but does not rotate...
drive also exist. Their name comes from one of their earliest and archetypal applications, tool and die work
Tool and die maker
Tool and die makers are workers in the manufacturing industry who make jigs, fixtures, dies, molds, machine tools, cutting tools , gauges, and other tools used in manufacturing processes...
, where they are used to create the precise contours of dies
Die (manufacturing)
A die is a specialized tool used in manufacturing industries to cut or shape material using a press. Like molds, dies are generally customized to the item they are used to create...
or molds
Moldmaker
Moldmaker is the designation for a profession in the metalworking and ceramics industry. It is a variety of the profession of the toolmaker. The moldmaker produces molds for the injection molding , die casting and ceramics industries....
. Especially before the advent of widespread CNC
Numerical control
Numerical control refers to the automation of machine tools that are operated by abstractly programmed commands encoded on a storage medium, as opposed to controlled manually via handwheels or levers, or mechanically automated via cams alone...
usage, they were heavily relied upon for contouring via manual skill comparable to a sculptor's
Sculpture
Sculpture is three-dimensional artwork created by shaping or combining hard materials—typically stone such as marble—or metal, glass, or wood. Softer materials can also be used, such as clay, textiles, plastics, polymers and softer metals...
. CNC now provides much of the contouring for die and mold interior surfaces, but die grinders are still very useful for hundreds of cutting needs, from sculpture-like contouring in the absence of CNC, to cut-off of bar stock
Bar stock
Bar stock, also colloquially known as billet, is a common form of raw purified metal, used by industry to manufacture metal parts and products....
, to any of the cutting and grinding needs of fabrication
Fabrication (metal)
Fabrication as an industrial term refers to building metal structures by cutting, bending, and assembling. The cutting part of fabrication is via sawing, shearing, or chiseling ; torching with handheld torches ; and via CNC cutters...
, such as in the work of welders, boilermakers, millwrights, ironworkers (steel erectors), sheet metal workers (such as auto body workers
Coachwork
Coachwork is the body of a horse-drawn coach or carriage, a motor vehicle , a railroad car or railway carriage. Usually reserved for bodies built on a separate chassis, rather than being of unitary or monocoque construction...
and HVAC
HVAC
HVAC refers to technology of indoor or automotive environmental comfort. HVAC system design is a major subdiscipline of mechanical engineering, based on the principles of thermodynamics, fluid mechanics, and heat transfer...
technicians), to woodworking
Woodworking
Woodworking is the process of building, making or carving something using wood.-History:Along with stone, mud, and animal parts, wood was one of the first materials worked by early humans. Microwear analysis of the Mousterian stone tools used by the Neanderthals show that many were used to work wood...
(especially cabinet making
Cabinet making
Cabinet making is the practice of using various woodworking skills to create cabinets, shelving and furniture.Cabinet making involves techniques such as creating appropriate joints, dados, bevels, chamfers and shelving systems, the use of finishing tools such as routers to create decorative...
), hacking, and other hobby or business pursuits. Die grinders are often used for engraving
Engraving
Engraving is the practice of incising a design on to a hard, usually flat surface, by cutting grooves into it. The result may be a decorated object in itself, as when silver, gold, steel, or glass are engraved, or may provide an intaglio printing plate, of copper or another metal, for printing...
, cylinder head porting
Cylinder head porting
Cylinder head porting refers to the process of modifying the intake and exhaust ports of an internal combustion engine to improve the quality and quantity of the air flow. Cylinder heads, as manufactured, are usually suboptimal due to design and manufacturing constraints...
, and general shaping of a part.
Die grinders are very similar to rotary tool
Rotary tool
A rotary tool is a hand held power tool with a variety of rotating accessory bits and attachments that can be used for cutting, carving, sanding, polishing and many other applications....
s, and in fact some people do not make any distinction between them. The difference between a die grinder and a rotary tool is mainly one of mental classification rather than etic traits. Die grinders are thought of as industrial tools, whereas rotary tools are thought of as tools for the residential mass-consumer end-user. There is overlap, though, as many consumers own die grinders, and many industrial users have rotary tools. The distinction is not very significant. Die grinders may feature heavier construction (such as being made of die-cast metal
Die casting
Die casting is a metal casting process that is characterized by forcing molten metal under high pressure into a mold cavity. The mold cavity is created using two hardened tool steel dies which have been machined into shape and work similarly to an injection mold during the process...
rather than molded plastic) and higher top speeds for the spindle
Spindle (tool)
In machine tools, a spindle is a rotating axis of the machine, which often has a shaft at its heart. The shaft itself is called a spindle, but also, in shop-floor practice, the word often is used metonymically to refer to the entire rotary unit, including not only the shaft itself, but its bearings...
(some can exceed 30,000 RPM
Revolutions per minute
Revolutions per minute is a measure of the frequency of a rotation. It annotates the number of full rotations completed in one minute around a fixed axis...
unloaded). All modern examples of what people call rotary tools have plastic bodies.
Methods of cutting action
The cutting may be done in various ways, including:- Grinding with bonded abrasive stones (called by various names, such as mounted stones, mounted points, or grinding points)
- Machining with a burrBurr (cutter)Burrs are small cutters used in die grinders, rotary tools or dentist's drills. The name may be considered appropriate when their small sized head is compared to that of a seed of the burr fruit or the teeth compared to a metal burr.To maintain the correct surface speed and cutting conditions...
or small drill bitDrill bitDrill bits are cutting tools used to create cylindrical holes. Bits are held in a tool called a drill, which rotates them and provides torque and axial force to create the hole. Specialized bits are also available for non-cylindrical-shaped holes....
or endmillEndmillAn endmill is a type of milling cutter, a cutting tool used in industrial milling applications. It is distinguished from the drill bit, in its application, geometry, and manufacture... - Sanding with coated abrasiveCoated abrasiveA coated abrasive is an abrasive grain bonded to a flexible substrate using adhesives. Common substrates are paper, cloth, vulcanized fiber, and plastic films and come in grit sizes range from very coarse to ultrafine...
, such as small drums made of sandpaper mounted on an expanding rubber mandrelMandrelA mandrel is one of the following:* an object used to shape machined work.* a tool component that grips or clamps materials to be machined.* a tool component that can be used to grip other moving tool components.- Variants :...
(also called an arbor) - HoningHoningHoning may refer to:* Honing , machining a surface by scrubbing an abrasive stone against it* Sharpening edged tools with a manual hone* Henkjan Honing , Dutch musician* Honing, Norfolk, English village* Playing Heroes of Newerth...
with fine-grit mounted points - LappingLappingLapping is a machining operation, in which two surfaces are rubbed together with an abrasive between them, by hand movement or by way of a machine.This can take two forms...
with lapping compound and a mounted lap to embed it - Polishing or buffing with cloth or fiber drums or flaps and polishing compound
Types of cutters
- Mounted stones of many shapes and various [small or medium] sizes (also called mounted points or grinding points)
- BurrsBurr (cutter)Burrs are small cutters used in die grinders, rotary tools or dentist's drills. The name may be considered appropriate when their small sized head is compared to that of a seed of the burr fruit or the teeth compared to a metal burr.To maintain the correct surface speed and cutting conditions...
of many shapes and various [small or medium] sizes (also called rotary files) - Small drill bitDrill bitDrill bits are cutting tools used to create cylindrical holes. Bits are held in a tool called a drill, which rotates them and provides torque and axial force to create the hole. Specialized bits are also available for non-cylindrical-shaped holes....
s - Small endmillEndmillAn endmill is a type of milling cutter, a cutting tool used in industrial milling applications. It is distinguished from the drill bit, in its application, geometry, and manufacture...
s - Small disc-shaped sawSawA saw is a tool that uses a hard blade or wire with an abrasive edge to cut through softer materials. The cutting edge of a saw is either a serrated blade or an abrasive...
blades or milling cutterMilling cutterMilling cutters are cutting tools typically used in milling machines or machining centres . They remove material by their movement within the machine or directly from the cutter's shape .-Features of a milling cutter:Milling cutters come in several shapes and many sizes...
s - Small abrasive cut-off wheels, which work like saw blades except via abrasive cutting rather than sawing per se
- Small sanding drums
- Small sanding flap wheels
- Small cloth or fiber wheels, drums, and flap wheels (for holding polishing compound)
- Mounted laps
Methods of holding the cutter
The cutter is usually held in a colletCollet
A collet is a holding device—specifically, a subtype of chuck—that forms a collar around the object to be held and exerts a strong clamping force on the object when it is tightened, usually via a tapered outer collar. It may be used to hold a workpiece or a tool.A collet is a sleeve with a ...
, which is a convenient means of chucking
Chuck (engineering)
A chuck is a specialized type of clamp used to hold an object, usually an object with radial symmetry, especially a cylindrical object. It is most commonly used to hold a rotating tool or a rotating workpiece...
in this application and provides the concentricity needed for high-RPM use. It also allows for quick changes in cutters. In some applications, other quick-change indexable
Indexing (motion)
Indexing in reference to motion is moving into a new position or location quickly and easily but also precisely. After a machine part has been indexed, its location is known to within a few hundredths of a millimeter , or often even to within a few thousandths of a millimeter , despite the fact...
chucking systems can be used, similar to the indexable chucking types now commonly found on consumer pistol-grip drill
Drill
A drill or drill motor is a tool fitted with a cutting tool attachment or driving tool attachment, usually a drill bit or driver bit, used for drilling holes in various materials or fastening various materials together with the use of fasteners. The attachment is gripped by a chuck at one end of...
s.
Personal protective equipment (PPE)
The most universal safety precaution in die grinder use is to protect one's eyes by wearing safety glasses.Other common PPE
Personal protective equipment
Personal protective equipment refers to protective clothing, helmets, goggles, or other garment or equipment designed to protect the wearer's body from injury by blunt impacts, electrical hazards, heat, chemicals, and infection, for job-related occupational safety and health purposes, and in...
in die grinder use includes:
- Other eye and face protection, such as safety gogglesGogglesGoggles or safety glasses are forms of protective eyewear that usually enclose or protect the area surrounding the eye in order to prevent particulates, water or chemicals from striking the eyes. They are used in chemistry laboratories and in woodworking. They are often used in snow sports as well,...
(basically "safety glasses with sides too") or a face shield, which is simply a polycarbonate window, hanging from a headband, between one's face and the work. All eye protectors come in clear versions as well as various levels of shading (for grinding that produces enough sparks to warrant shading, like torching or welding do). - Hearing protection, such as ear plugs or headphonesHearing protectorsHearing protectors are devices designed to prevent Noise-Induced Hearing Loss , a type of post-lingual hearing impairment.* Earplug – A device inserted into the ear canal.* Earmuffs – Objects designed to cover a person's ears....
(die grinders are often quite loud, even just running unloaded, but even more so while cutting). - Skin protection, such as work gloves (and in some special applications, fire-retardant clothing because of the sparks, although the sparks are usually harmless in most applications).
- Protection for the respiratory and alimentary tracts (mouth, throat, lungs, gut), such as simple paper maskSurgical maskA surgical mask also known as a procedure mask is intended to be worn by health professionals during surgery and at other times to catch the bacteria shed in liquid droplets and aerosols from the wearer's mouth and nose....
s or, in special applications, a respiratorRespiratorA respirator is a device designed to protect the wearer from inhaling harmful dusts, fumes, vapors, or gases. Respirators come in a wide range of types and sizes used by the military, private industry, and the public...
. Masks may be trivial in many applications but important in others. Any abrasive cutting generates dust, from both the abrasive itself and from the workpiece. Depending on the materials and amounts, masks may be needed.
Safety features built into the tool
Most pneumatic die grinder throttles (also called triggers) feature a spring-loaded "kickstand" mechanism between the throttle lever and the body of the grinder. This prevents the throttle from opening (being pressed down towards the body of the grinder) without operator intervention and inhibits accidental activation. It is similar in principle to the safety catchesSafety (firearms)
In firearms, a safety or safety catch is a mechanism used to help prevent the accidental discharge of a firearm, helping to ensure safer handling....
used on many handgun
Handgun
A handgun is a firearm designed to be held and operated by one hand. This characteristic differentiates handguns as a general class of firearms from long guns such as rifles and shotguns ....
s.
Tools with electric motors often have electrical safety features such as grounded cases (wired to a grounding conductor, which uses the grounding prong on a plug) or double insulation. Some may have both, but more often not, because regulatory requirement
Regulation
Regulation is administrative legislation that constitutes or constrains rights and allocates responsibilities. It can be distinguished from primary legislation on the one hand and judge-made law on the other...
s require only one or the other.