The angle formed as the regulating wheel swivels to allow the part to pass. The regulating wheel angle of inclination provides axial thrust that feeds the workpiece past the grinding wheel during operation.
Axial
A long or parallel to the axis of the workpiece. During throughfeed grinding the part must move in an axial direction.
Bearing Surface
The circular underside of the bolt head that makes contact with the part. During centerless grinding, the bearing surface of the work guide on the entrance side of the regulating wheel must be set behind the regulating wheel face by a specific amount.
Center
A hardened, pointed, cylindrical component used to hold one end of a workpiece during center-type cylindrical grinding. The tip of a center is inserted into a matching hole on the end of a workpiece.
Centerless Grinding
A common grinding operation during which a cylindrical part is supported on a work rest blade and guided between a grinding wheel and a regulating wheel. Centerless grinding is a type of cylindrical grinding.
Chatter Marks
Surface imperfections on the workpiece caused by vibrations of the grinding wheel. Positioning the work rest blade too high above the centerline of the grinding and regulating wheels often results in chatter marks.
Chattering
Also called whipping, the occasional unwanted vibration between components. Chattering is often caused by kinks or bends in a part.
Chuck
A device that holds a workpiece in place as it rotates. The chuck commonly has three or four jaws that can be adjusted to fit various sizes.
Cylindrical Grinding
A common grinding process during which a cylindrical part is held on each end and rotated as a grinding wheel is guided along its length. Centerless grinding is a type of cylindrical grinding.
Diameter
The distance from one edge of a circle to the opposite edge that passes through the center. Accurate setup of a centerless grinder ensures consistent workpiece diameter.
End Stock
Device that halts or prevents workpiece motion once the workpiece is ground to a specified location and depth. During throughfeed grinding, the regulating wheel angle holds the workpiece firmly against the end stop.
Face
In grinding, the part of the wheel that contacts the workpiece. The truing angle ensures that the workpiece makes a straight line of contact with the regulating wheel face.
Feed Rate
The rate at which the grinding wheel and the workpiece move in relation to one another. The regulating wheel angle of inclination provides the axial thrust that determines workpiece feed rate.
Feeler Gauge
A device sometimes used to determine if there is proper clearance between components on a machine. A feeler gauge is often used to ensure sufficient clearance between the regulating wheel and work guide for the workpiece to pass through.
Finish
The degree of "smoothness" of a workpiece surface. Accurate setup of a centerless grinder ensures appropriate workpiece finish.
Finish Grinding
An abrasive process that improves the surface of the part. Finish grinding emphasizes tight tolerances and smooth surface finish.
Form Grinding
Type of centerless grinding that uses a specialized edge, or profile, that is added to the face of a wheel. The "form" or profile is then imparted into the workpiece during grinding.
Grade
The strength of the bond in an abrasive wheel. Using a wheel with a softer grade during centerless grinding helps to prevent chatter marks.
Grinding Wheel
A wheel made of a bonded abrasive used to remove material from a workpiece surface. A grinding wheel rotates and shears away microscopic chips of material and can produce very fine surface finishes.
Hydraulic Feeding Mechanism
Device that typically controls the rate at which the truing tool travels across the grinding wheel.
Infeed Grinding
Similar to plunge grinding, a method of centerless grinding in which the workpiece is held stationary while the grinding wheel is fed into the workpiece at a specified location and depth.
Lobing
Deviation from workpiece roundness. Lobing is prevented by proper setup of the centerless grinder.
Lower Slide
The device attached to the swivel plate that moves the regulating wheel toward or away from the workrest blade. The correct positioning of the workpiece above the top of the lower slide assists in part roundness.
Periphery
The outer edge of a workpiece. During centerless grinding, any high spot on the periphery of the workpiece causes workpiece lobing.
Pick-up
Also called scoring, a centerless grinding problem that occurs when excessive pressure from the work rest blade causes tiny chips to fuse to the blade. Pick-up often occurs when the blade is too hard for the grinding operation.
Profile Truing Attachment
A system used to true a form grinding wheel for centerless grinding. The profile truing attachment is used to impart a particular shape into the form grinding wheel, which is then used to impart a particular shape into the workpiece.
Rate Of Traverse
Speed at which the truing tool travels across the grinding wheel. The truing tool rate of traverse is typically controlled by a hydraulic feeding mechanism.
Regulating Wheel
A wheel, usually made of plastic or rubber bond, used during centerless grinding to rotate the workpiece and pull it through the operation. The regulating wheel controls workpiece rotational speed and feed rate.
Rough Grinding
Relatively aggressive cutting or grinding done with little regard for surface finish.
Roundness
The quality of a cylindrical workpiece characterized by the entire length of the workpiece having the same diameter relative to a common axis. All points on the exterior surface of a perfectly round cylindrical workpiece are equidistant from the axis of the workpiece.
Scoring
Also called pick-up, a centerless grinding problem that occurs when excessive pressure from the work rest blade causes tiny chips to fuse to the blade. Scoring often occurs when the blade is too hard for the grinding operation.
Squared
Directly aligned with the surface of another object. The work guide at the rear of the regulating wheel must be squared with the regulating wheel.
Tandard Truing Unit
A system used to true a grinding wheel in centerless grinding. This system uses a diamond dresser to true the face of a grinding wheel for straight cylindrical parts.
Stock
Raw workpiece material that is removed during a grinding pass or operation.
Through Feed
In grinding, the movement of a workpiece as it travels through an operation.
Throughfeed Grinding
A method of centerless grinding in which the regulating wheel and work guides feed the workpiece past the grinding wheel in a straight line. Throughfeed grinding is used primarily to grind straight cylindrical workpieces with no obstructive features.
Tolerance
An unwanted but acceptable variation from a specified dimension. Accurate setup of a centerless grinder ensures accurate workpiece tolerance.
Truing Angle
The angle formed by the truing device that matches the regulating wheel angle of inclination. The truing angle creates a slightly convex regulating wheel face, which enables a complete line of contact between the regulating wheel and workpiece during centerless grinding.
Whipping
Also called chattering, the occasional unwanted vibration between components. Whipping is often caused by kinks or bends in a part.
Work Guide
A device used in centerless grinding that prevents the workpiece from moving too far toward either the regulating wheel or grinding wheel. Work guides help maintain consistent workpiece diameter during throughfeed grinding.
Work Rest
A part of a centerless grinding machine that supports the workpiece as it is ground. Work guides are mounted to the work rest.
Work Rest Blade
A device, usually with an angled edge, that supports cylindrical parts during centerless grinding. The above-center positioning of the work rest blade produces concentricity of the workpiece.
Work Speed
The rotational speed of the workpiece. The regulating wheel rotational speed determines work speed.
Additive
A substance added in small amounts to another substance or material to change or improve its performance.
American National Standards Institute
A private, non-profit organization that administers and coordinates voluntary standards and systems.
Bonding Material
The material that holds abrasive grains together in a grinding tool. Bonding materials may consist of rubber, metal, or other material.
Chatter Mark
An irregular mark left on a workpiece that has been ground with a wheel that is out of true.
Chip
An unwanted piece of metal that is removed from a workpiece. Chips are formed when a tool cuts or grinds metal.
Coolant
A substance, usually liquid, used to reduce or maintain the temperature of a part being ground.
Crush Dressing
The use of rolls or special forms to dress the face of a grinding wheel to a specific shape or contour.
Cutting
In grinding, the main action that occurs when sharp grains dig into the workpiece and remove chips.
Cutting Fluid
A liquid used during grinding to clean, cool, and lubricate the grinding site.
Dressing
The removal of swarf, dull grains, and bonding material from a grinding wheel. Essentially, dressing sharpens the wheel.
Dressing Tool
A device used to remove loading and sharpen a grinding wheel. It might consist of an abrasive stick, a single-point diamond, or other tool.
Fracture
The breaking apart of grains in an abrasive wheel during grinding. It is part of the wheel's self-sharpening process.
Friability
The ability of abrasive grains to fracture and self-sharpen under stress.
Glazing
The unwanted formation of a smooth surface on a grinding wheel. Glazing occurs when the heat from grinding reacts with a loaded wheel.
Grain
A small, hard particle or crystal of abrasive material.
Grinding
The use of an abrasive to wear away at the surface of a workpiece and change its shape.Grinding Wheel
A wheel made of a bonded abrasive used to grind the surfaces of parts.
Horizontal Grinding
A grinding machine with a spindle that is parallel to the work surface.
Loading
A build up of swarf in a grinding wheel that clogs the spaces between grains.
Lubricant
A substance, often a liquid, used to reduce or prevent friction, resistance, heat, and wear during grinding.
Machining
The process of removing metal to form or finish a part, either with traditional methods like turning, drilling, cutting, and grinding, or with less traditional methods that use electricity or ultrasound.
Offhand Grinding
Generally, grinding in which the workpiece is held in the operator's hand and placed against the grinding wheel. It is used for material removal without regard to surface finish.
Out Of True
The loss of a grinding wheel's original shape resulting in a wheel that is no longer symmetrical.
Peripheral Wheel
A grinding wheel in which the outer rim is in contact with the workpiece.
Plowing
An action that occurs during grinding when dull grains push into the workpiece without cutting it. Plowing leaves grooves in the work surface.
Ring Test
A manual test used to determine the presence of damage in bonded grinding wheels. Operators suspend a wheel loosely and tap it with a tool. Wheels that emit a ringing sound are likely undamaged.
Roll
A hard wheel used in crush dressing to improve or shape the surface of a grinding wheel.
Rubbing
A sliding action that occurs during grinding when dull grains glide over the surface of a workpiece without cutting it.
Side Wheel
A grinding wheel in which the front portion, or face, is in contact with the workpiece.
Swarf
The gritty combination of chips, abrasive grains, and worn bonding material that is produced during grinding.
Tool Grinding
A specialized type of grinding performed to sharpen cutting tools. Tool grinding is often very precise.
Truing
The dressing of a wheel in order to return the wheel to its original shape.
Void
An empty space between abrasive grains on a grinding wheel where chips collect.
Workpiece
A part that is being worked on. It may be subject to grinding, cutting, welding, forming, or other operations.
