| abrasive grains |
A hard, sharp particle of material, generally aluminum oxide or silicon carbide and sometimes diamond or cBN. Abrasives are used to wear down or rub away material. |
| angle of inclination |
The angle at which the centerline of the regulating wheel spindle is set in relation to the centerline of the grinding wheel. The regulating wheel angle of inclination provides axial thrust that feeds the workpiece past the grinding wheel during centerless grinding. |
| angular-bed grinders |
A type of centerless grinder that uses the regulating wheel to rotate the workpiece until it reaches the desired speed. On an angular-bed grinder, the workpiece contacts the grinding wheel only after it has reached the desired speed. |
| axial |
Running straight along or parallel to the axis of a workpiece. Axial as well as rotational movement are required for a workpiece to be properly ground during centerless grinding. |
| backing plate |
A component that, along with the grinding wheel, rotates a workpiece and pushes it into two hard shoes during shoe-type internal centerless grinding. A backing plate is often a magnetic chuck. |
| bar stock |
Raw material purchased from metal manufacturers in the form of long bars. Bar stock may be round, square, or hexagonal. |
| bed |
The foundation of a grinding machine that supports all other machine components. The bed on a grinder is the bottom portion of the machine. |
| bond |
The material that holds abrasive grains together in a grinding wheel. Bond, or bonding material, can be vitrified, resin, rubber, or metal. |
| bonding material |
The material that holds abrasive grains together in a grinding wheel. Bonding material, or bond, can be vitrified, resin, rubber, or metal. |
| centerless grinding |
A type of cylindrical grinding in which a cylindrical part is supported on a work rest blade and guided between a grinding wheel and a regulating wheel. Centerless grinding requires that both the workpiece and the grinding wheel rotate. |
| chip |
A small piece of material that is removed from a workpiece. Chips are formed when a tool cuts or grinds a material. |
| circumference |
The boundary or perimeter around a circle. Circumference measures the distance around a circle. |
| concentric |
Having a common center or sharing the same axis. Concentric circles on a grinding wheel should share a center point at this axis. |
| concentricity |
A geometric tolerance that describes the location of opposing points in cylindrical features with respect to their center axes. Concentricity can be achieved on a cylindrical part using shoe-type internal centerless grinding. |
| coolant |
A complex liquid consisting of several chemicals that is used during grinding to clean, cool, and lubricate the wheel and workpiece. Coolant, or grinding fluid, also washes away swarf. |
| cylindrical grinding |
A common grinding process that holds a cylindrical part on each end or uses a chuck or collet to hold the part during grinding. Cylindrical grinding rotates both the part and grinding wheel. |
| cylindricity |
A three-dimensional form tolerance that describes the allowable variability in the shape and appearance of a cylinder. Cylindricity states how close a part is to being perfectly cylindrical. |
| dressing |
To remove swarf, dull grains, and bonding material from a grinding wheel by fracturing away the wheel surface. Dressing also sharpens the wheel. |
| end stop |
A device that halts or prevents workpiece motion once the workpiece is ground to a specified location and depth. End stops are used in endfeed centerless grinding. |
| endfeed |
A method of centerless grinding in which the workpiece is fed into the grinding and regulating wheels until the workpiece contacts an end stop. Endfeed centerless grinding is used to taper the end of a workpiece. |
| external cylindrical centerless grinder |
The most common form of centerless grinder. External cylindrical centerless grinders perform either throughfeed or infeed centerless grinding. |
| fracturing |
The breaking apart of grains in an abrasive wheel during grinding to create new cutting edges. Fracturing is part of the wheel’s self-sharpening process. |
| glazing |
The unwanted formation of a smooth surface on a grinding wheel. Glazing occurs when the heat from grinding reacts with a wheel. |
| grinding |
Using an abrasive to wear away a workpiece surface and achieve highly accurate measurements. Grinding operations commonly use abrasive grains bonded into a wheel shape. |
| grinding fluid |
A complex liquid consisting of several chemicals that is used during grinding to clean, cool, and lubricate the wheel and workpiece. Grinding fluid also washes away swarf. |
| grinding variables |
The measureable rates of movement of grinding wheels and workpieces. Grinding variables include speed, feed, and depth of cut. |
| grinding wheel |
A wheel made of abrasive grains that are held together by a bonding material. A grinding wheel rotates and grinds away microscopic chips of material and can produce very fine surface finishes. |
| hard shoes |
A component against which the workpiece is pushed during internal centerless grinding to provide accurate concentricity. Two hard shoes are used in shoe-type internal centerless grinding. |
| horizontal-bed grinders |
A type of centerless grinder that causes the workpiece to rotate only after it touches the rotating grinding wheel. Horizontal-bed grinders are the most common design of centerless grinders. |
| infeed centerless grinding |
A centerless grinding process in which workpieces do not move all the way through the machine. Infeed centerless grinding involves the regulating wheel and work rest pushing the workpiece into the grinding wheel. |
| inner diameter |
ID. The interior surface of a spherical or cylindrical object. Inner diameter is also known as internal diameter. |
| loading |
A buildup of swarf in a grinding wheel that clogs the spaces between grains. Dressing and truing a grinding wheel prevent loading. |
| lower slide |
The device that moves the regulating wheel and work rest blade toward and away from the grinding wheel. The lower slide is attached to the swivel plate. |
| lower slide |
The device that moves the regulating wheel toward and away from the work rest blade. A lower slide is attached to a swivel plate. |
| machine tool |
A power-driven machine that uses a cutting tool or abrasive wheel to remove material from a workpiece. Machine tools include centerless and cylindrical grinders. |
| meters per second |
m/s. A measurement of speed that is a direct function of the workpiece or tool diameter and its rate of rotation. Meters per second is a metric measurement. |
| OD |
outer diameter. The external surface of a workpiece. OD centerless grinding operations include throughfeed, infeed, and endfeed grinding. |
| outer diameter |
OD. The external surface of a workpiece. Outer diameter centerless grinding operations include throughfeed, infeed, and endfeed grinding. |
| periphery |
The perimeter, or edge, of an object. Many types of grinding wheels grind with their periphery. |
| pressure roll |
A wheel that, along with the support roll, helps to hold the workpiece during internal centerless grinding. A pressure roll is used in roll-type internal centerless grinding. |
| recessed wheel |
An abrasive wheel that resembles a flat disk with a depressed area surrounding the wheel center. Recessed wheels are wider at their periphery than their center. |
| regulating roll |
A wheel used to rotate the workpiece and pull it through the internal centerless grinding process. A regulating roll is used in roll-type internal centerless grinding. |
| regulating wheel |
A grinding wheel commonly made of resin bond that is used to slow a workpiece's rotation against a grinding wheel. A regulating wheel, or control wheel, also drives the workpiece axially across the work rest blade. |
| regulating wheel housing |
The part of a centerless grinder on which the regulating wheel is mounted. The regulating wheel housing is mounted to the upper slide and contains the regulating wheel and regulating wheel spindle. |
| revolutions per minute |
rpm. The number of revolutions that a spindle or grinding wheel completes in one minute. Revolutions per minute is a measurement of speed. |
| roll-type internal |
A type of centerless grinding in which three rolls are used to rotate and support a workpiece while a grinding wheel machines its inner diameter. Roll-type internal centerless grinding involves one large regulating roll that rotates the workpiece while a pressure roll and a support roll hold the workpiece in place during the grinding process. |
| rotational speed |
The rate of rotational movement of the workpiece or grinding or regulating wheel. Rotational speed is measured in revolutions per minute (rpm). |
| shoe-type internal |
A type of centerless grinding in which a backing plate pushes a workpiece into two hard shoes while a grinding wheel machines its inner diameter. Shoe-type internal centerless grinding maintains concentricity between the workpiece's inner and outer diameter. |
| spindle |
A rotating component of a machine tool. Typically, grinding and regulating wheels are mounted on a spindle. |
| spindle speed |
The rate of rotational movement of the grinding or regulating wheel. Spindle speed is measured in revolutions per minute (rpm). |
| stock |
Raw material used to make manufactured parts. Stock is available in standard shapes, such as long bars, plates, or sheets. |
| straight wheel |
A common type of abrasive tool used in grinding and cutoff operations. Straight wheels generally appear as flat disks. |
| support roll |
A wheel that, along with the pressure roll, helps to hold the workpiece during internal centerless grinding. A support roll is used in roll-type internal centerless grinding. |
| surface feet per minute |
sfm. A measurement of speed that is a direct function of the workpiece or tool diameter and its rate of rotation. Surface feet per minute measures the number of feet that a location on a rotating component travels in one minute. |
| surface finish |
The smoothness of a part surface after it has gone through all grinding operations. Surface finish is the complete, desired surface. |
| surface speed |
The uniform rate at which the regulating wheel revolves against the workpiece during centerless grinding. Surface speed controls the work speed of the workpiece. |
| swarf |
The gritty combination of chips, abrasive grains, and worn bonding material that is produced during grinding. Swarf can clog a grinding wheel and cause it to function improperly. |
| swivel plate |
The device that tilts or aligns the regulating wheel parallel to the grinding wheel. A swivel plate is mounted to the bed of a grinder. |
| swivel plate |
The device that tilts or aligns the regulating wheel parallel to the grinding wheel.The swivel plate is mounted to the bed of a grinder. |
| tapered |
A linear increase or decrease in the diameter of an object. A taper is ground into a workpiece using endfeed grinding. |
| through feed rate |
The rate at which the workpiece passes axially between the grinding and regulating wheels. Through feed rate is controlled by the regulating wheel. |
| throughfeed |
A method of centerless grinding in which the regulating wheel and work rest guides feed the workpiece past the grinding wheel in a straight line. In throughfeed grinding, the regulating wheel moves the part completely past the grinding wheel. |
| tolerance |
The allowable deviation from a given dimension. Tolerances indicate the allowable difference between a physical feature and its intended design. |
| truing |
To restore a grinding wheel to its original, intended shape. Truing ensures that a wheel retains a concentric round shape. |
| upper slide |
The device that moves the regulating wheel and work rest blade toward and away from the grinding wheel. An upper slide is attached to a swivel plate. |
| upper slide |
The device that moves the regulating wheel toward and away from the work rest blade. The upper slide is attached to the swivel plate. |
| wheel speed |
The peripheral rate of movement of the grinding wheel. Wheel speed is measured in surface feet per minute or meters per second. |
| wheelhead |
The part of the grinding machine on which the wheel is mounted. On a centerless grinder, the wheelhead contains the grinding wheel and grinding wheel spindle. |
| work rest |
A centerless grinder component that supports the workpiece as it is ground. The work rest is mounted on the lower slide and supports the work rest blade. |
| work rest blade |
A device that supports cylindrical parts during centerless grinding. Work rest blades often have an edge that angles toward the regulating wheel. |
| work rest guides |
A centerless grinder component located at the beginning and end of the machine to position the workpiece as it enters and exits. Work rest guides are used for throughfeed centerless grinding. |
| work speed |
The peripheral speed of the workpiece. Work speed is approximately equal to the surface speed of the regulating wheel. |
| workpiece |
A part that is in the process of being manufactured. A workpiece may be a complete product by itself or one component of a product consisting of many parts. |