Abstract: A manufacturing method comprises the following steps. A shape of a first cross-section of a to-be-ground portion of a workpiece to be ground by a grinding wheel is obtained. The grinding wheel is manufactured according the shape of the first cross-section. When the to-be-ground portion is contacted and to be ground by the grinding surface, a first intersection line formed by the first cross-section and one of reference planes has a first length, second intersection lines formed by the grinding surface and one of the reference planes have second lengths, and all ratios between the first length of the first intersection line and a sum of the second lengths of the second intersection lines formed by the same reference plane are equal to each other. The reference planes are perpendicular to the rotation axis of the grinding wheel.

Abstract: An electric knife sharpener includes an accommodating unit including a base and an upper cover with a V-shaped opening slot, a driving unit fixed on the base and including a motor and an eccentric wheel, a linkage unit including a linkage mechanism and an upper fixing seat with two limiting rods thereof pivotally connected to an upper part of the upper fixing seat, and a grinding unit. The linkage unit has a guide groove located in a pivot end thereof and coupled to two guiding blocks in a through hole of the upper fixing seat. The grinding unit includes two sharpening components. One end of each sharpening component is pivotally connected in a groove of the linkage mechanism, so that the two sharpening components form a cross arrangement and opposite openings are formed between the two sharpening components to cross a sharpening accommodating space.

Abstract: A polishing apparatus includes a polishing station to hold a polishing pad, a carrier head to hold a substrate in contact with a polishing pad at the polishing station, a camera positioned to capture an image of a lower surface of a consumable part when the consumable part moves away from the polishing pad, and a controller configured to perform an image processing algorithm on the image to determine whether the consumable part is damaged. The consumable part can be a retaining ring on a carrier head, or a conditioner disk on a conditioner head.

Abstract: The present invention relates to a laying machine for laying at least one flexible casing or tube, cable or wire including: a blade arrangement for making a trench in the ground, a consolidation and laying means being arranged behind the blade arrangement, for clearing and safe-guarding the trench from collapsing while laying at least one flexible casing or tube, cable or wire into the trench. A blade assembly comprising compartments for cooling fluid and air.

Abstract: An adjustable sharpener including a body having two sharpening slots, a first arm with a first abrasive element connected to a second arm with a second abrasive element, and a third arm with a third abrasive element connected to a fourth arm with a fourth abrasive element. The first and second abrasive elements are positioned in the first sharpening slot, and the third and fourth abrasive elements are positioned in the second sharpening slot. The adjustable sharpener also includes an adjuster connected to the body and an adjustment assembly connected to the adjuster, the first arm and the third arm. Linear movement of the adjuster causes rotational movement of the first arm and the third arm. In this regard, the adjuster allows the user to manually increase or decrease the sharpening angle between the abrasive elements in the sharpening slots.

Abstract: A polishing assembly for polishing of silicon wafers includes a polishing pad, a polishing head assembly, a temperature sensor, and a controller. The polishing head assembly holds a silicon wafer to position the silicon wafer in contact with the polishing pad. The polishing head assembly selectively varies a removal profile of the silicon wafer. The temperature sensor collects thermal data from a portion of the polishing pad. The controller is communicatively coupled to the polishing head assembly and the temperature sensor. The controller receives the thermal data from the temperature sensor and operates the polishing head assembly to selectively vary the removal profile of the silicon wafer based at least in part on the thermal data.

Abstract: This application presents a method and apparatus for cooling a through-ported cutting tool with a source of liquid CO2 with a compressed air line with a compressed air inlet and multiple CO2 injection capillary segments; the capillary segments interconnect to the same source of liquid CO2 and can have high pressure valves and throttles; the throttles have different sizes; a first capillary ends near the cutting tool; the second capillary ends near the compressed air inlet. Using a particular sequence of opening or closing the valves to the liquid CO2 to the capillaries, mixing with the compressed air provides and recycling the residual CO2, this invention provides for uniform and controlled cooling of the cutting tool within a certain temperature range.

Abstract: A coolant flow guide for grinder includes a base including a tilted bottom wall having a predetermined tilt angle, a peripheral wall disposed around the tilted bottom wall and defining with the tilted bottom wall a diversion channel having a top opening and a partition wall located on the tilted bottom wall to divide the diversion channel into two flow passages that slope downwardly to the diversion port, and a workpiece positioning unit mounted on the base above the flow passages for holding a workpiece. Thus, when the grinder is operated to grind the workpiece, the debris thus produced is carried by the applied coolant to flow through the flow passages to the outside of the base via the diversion port.

Abstract: This grinding wheel tool is provided with a cylindrically shaped head unit comprising a hollow area passing through the inside, and abrasive grains adhered across the entire outer peripheral surface of the head unit. A fluid is supplied in the hollow area, and in the head unit, communication holes are formed which communicate between the hollow area and the outer peripheral surface and which, from the radial direction of the head unit, are angled forwards in the direction of rotation. Hereby, it is possible to provide a grinding wheel tool which can greatly reduce clogging even in cases where a high amount of cutting chips are generated per unit time, such as in high-feed processing.

Abstract: A holding device, in particular a grinding disc, for a grinding member includes at least one support member that has at least one material opening configured for transverse transport of grinding dust to one side facing the grinding member in a plane parallel to a grinding surface. The holding device further includes at least one securing layer configured to secure the grinding member on the at least one support member. When decoupled from the grinding member, the at least one material opening is at least substantially open on a side facing the grinding member and on a side facing away from the grinding member is substantially delimited by the support member.

Abstract: The super abrasive wheel includes a core rotating around a rotation axis and a super abrasive layer bonded to the core. The core has a first surface and a second surface located opposite to the first surface. An annular first protrusion portion protruding in the direction away from the first surface is provided at a portion of the second surface that is surrounded with the super abrasive layer. A reference surface is provided in the second surface on the inside of the first protrusion portion. The height from the reference surface to the first protrusion portion is denoted as A. A top portion having the height B from the reference surface is provided at a portion of the second surface between the first protrusion portion and the super abrasive layer. The height B is greater than the height A.

Abstract: A supply device for a handheld power tool for a cutting grinder includes a cutting tool and a protective cover which at least partially surrounds the cutting tool. The supply device includes a U-shaped element which can be arranged on the protective cover and via which a fluid medium can be supplied to the cutting tool. The U-shaped element has a connection piece on which a coupling element can be arranged. On the coupling element a pipeline can be connected via which the fluid medium can be supplied to the U-shaped element through the connection piece. The coupling element can be turned about the axis of rotation of the connection pieces.

Abstract: A hand-guided power tool has a support arm and a tool member supported on the support arm. A drive motor is provided and a drive belt is rotatably driven by the drive motor and drives in turn the tool member. The support arm has a belt chamber in which the drive belt is arranged. The belt chamber is closed off relative to the environment and sealed off relative to the environment.

Abstract: A cooling system and method for a machining process. The system includes a coolant supply and a coolant activation assembly, where the coolant supply is configured to provide coolant to the coolant activation assembly. The coolant activation assembly includes a plurality of piezoelectric actuators. Each of the plurality of piezoelectric actuators is configured to emit a coolant stream and to impart an ultrasonic or megasonic vibration component to each coolant stream. The coolant activation assembly is configured to provide cooling to a focal point in a work zone by directing multiple coolant streams emitted by the plurality of piezoelectric actuators to the focal point such that multiple coolant streams converge at the focal point.

Abstract: A machining device for machining crankshafts has a rotationally driven disk-shaped base body with blade inserts arranged peripherally thereon. A first supply line for a cryogenic cooling medium is arranged concentrically with the axis of rotation and is thermally insulated in at least some sections. The tool has a plurality of second supply lines for the cryogenic cooling medium running across the axis of rotation and leading to the blade inserts, the second supply lines each being thermally insulated in at least some sections. A distributor unit connects the first supply line to at least one of the second supply lines for supplying the cryogenic cooling medium to at least one of the blade inserts. The cryogenic cooling medium can be conducted directly to the blade inserts which are engaged with the crankshaft that is to be machined.

Abstract: A programmable coolant nozzle system and method for grinding wheel machines. The system comprises a fluid manifold block that automatically or manually follows the wear of the grinding wheel, to position coolant jets tangential to the wheel surface throughout the life of the grinding wheel. The positioning is by an arcuate motion, through a parallelogram mechanism, to ensure that the coolant jets remain at the same angle to the grinding wheel surface throughout the entire range of motion.

Abstract: When a rare earth magnet block is cut or ground by a cutting or grinding tool, a jig is used for holding the magnet block in place. The jig comprises a base, a pair of metal support members disposed on opposite sides of the base and provided with grooves, and rubber rods received in the support member grooves such that the rubber rod partially protrudes from the groove and abuts on the groove bottom. The magnet block is rested on the base and clamped between the rubber rods. The volume of the groove is larger than the volume of the rubber rod.

Abstract: During grinding of mutually parallel edges of glass plates every edge of the glass plate is ground using a grinding tool or two grinding tools disposed one behind the other and cooling agent is directed from a side of the glass plate toward the grinding tool and supplied using a supply line divided via a redirection and separating segment into a plurality of fine streams of cooling agent, and a position of the grinding tool can be adjusted such that at least the position of the grinding tools relative to the assigned edge of the glass plate, which is passing through, is calibrated and the corners of the glass plate are ground to form a chamfer.

Abstract: According to one embodiment, a polishing method comprises pressing a substrate being rotated against a polishing pad being rotated and supplying slurry on the polishing pad, measuring a surface temperature of the polishing pad, and when the surface temperature is not less than a predetermined temperature, jetting jet stream containing supercooled droplets from a nozzle having a narrow portion toward the polishing pad.

Abstract: A grinding apparatus includes a base, a case, a transmission module, an inlet water module and drain module. The case is positioned on the base. The transmission module is positioned on the base, and includes a motor and a grinding plate. The motor drives the grinding plate to rotate. The inlet water module is configured for feeding water onto the grinding plates. The drain module includes a drain pan and a drain pipe. The drain pan is detachably attached to the case, the drain pipe is connected to the drain pan, and is exposed from the case.

Abstract: A system for grinding surgical needles made of refractory metal alloys such as tungsten-rhenium alloys includes a rotatable grinding wheel having a grinding surface, a layer of a binding material, such as a nickel binding material layer, overlying the grinding surface, and a plurality of abrasive particles, such as ABN600 abrasive particles, embedded within the binding material layer. The abrasive particles are similarly sized and the binding material layer has a thickness that is about 65% of the size of the similarly sized abrasive particles. The system includes a lubricating device adapted to apply a lubricant to an interface between the grinding surface and distal ends of needle blanks and a rotating element coupled with the rotatable wheel for rotating the grinding surface at about 10,000 surface feet per minute.

Abstract: A tool sharpening assembly suitable for sharpening cutting tools. In accordance with some embodiments, the apparatus has a rotatable abrasive surface, and a tool support structure which contactingly supports a body portion of a tool while a cutting surface of the tool is presented against the abrasive surface during a sharpening operation. A cooling mechanism operates to reduce a temperature of the tool.

Abstract: The present invention is an original direct motor-drive portable angle grinder with a disc type motor installed in a position adjacent to the grinding wheel and an outer motor rotating part coaxially and directly driving the grinding wheel. By means of the direct drive, the present invention prevents the emission of noise made by angle type transmission devices. Moreover, an inertial body is installed on the rotating housing that is integrated with the rotating part to form a flywheel or the rotating housing and the inertial body are integrated into a single reinforced structure to enable a flywheel function in order to improve the grinding, polishing and machining or cutting abilities of the grinding wheel.

Abstract: A machining method comprises selecting a finished surface dimension and a material property for a working surface, defining a working temperature range based on the selected material property, and defining a machining power based on the working temperature range. The machining power depends on a removal rate and a specific heat of the working surface. The working surface is machined at the removal rate to achieve the finished surface dimension, and the machine power is controlled to maintain the working surface within the working temperature range. The working surface is heated or cooled from the working temperature range to a transition temperature range, such that the selected material property is preserved in the working surface.

Abstract: A glass edge finishing system, a belt assembly and a method are described herein for finishing an edge of a glass sheet. The glass edge finishing system comprises: (a) a base; and (b) one or more belt assemblies located on the base, where each belt assembly includes: (i) a support frame; (ii) a motor; (iii) a pair of pulleys rotatably mounted on the support frame and driven by the motor; (iv) a belt engaged to and driven by the pair of pulleys, where the belt contacts and finishes the edge of the glass sheet; (v) a belt cleaning device that removes glass debris from the belt as the belt moves past the belt cleaning device; and (vi) a cleaning containment enclosure within which there is located the belt cleaning device, where the cleaning containment enclosure contains the glass debris removed from the belt by the belt cleaning device.

Abstract: A tool sharpening assembly (100) suitable for sharpening cutting tools (140,350,366,546,562). In some embodiments, a wedge-shaped port is formed between a rotational first abrasive surface (160,262) and a stationary second abrasive surface (162,264) to sharpen a distal cutting edge (146) of a cutting tool (140,230,546). In other embodiments, a cooling mechanism (136,326,330,334,338) actively draws heat generated during a sharpening operation from a tool (140) and through a tool support structure (170,234,328,332) contactingly supporting the tool, in further embodiments, a rotatable abrasive slotted disc (364) comprises at least one inspection aperture (372) formed from an interior sidewall (390) with upper and lower leading and trailing edges (396,398,400,402) of non-uniform separation distance. In other embodiments, a cylindrical drum abrasive member (572) is provided with an associated stationary support plate (574).

Abstract: In various embodiments, a coolant delivery apparatus is presented. Namely, a coolant delivery apparatus comprises a plurality of internal channels configured to provide coolant to the work face of a grinding wheel.

Abstract: Provided is a polishing apparatus comprising a lower stool (12), a motor (18a) and a speed reducer (19a) for driving the lower stool, and a box (17) for covering at least the portion of the lower stool below the working action face. The polishing apparatus polishes a wafer by forcing the wafer to contact the lower stool and by rotating the lower stool. The box has its inside separated by partitions (31a and 31b) into a plurality of regions, and the motor for driving the lower stool is arranged in a region other than the region containing the lower stool. The polishing apparatus can manufacture a wafer of a stable shape, irrespective of the time elapsed from the running start and the presence/absence of the stop of the polishing apparatus.

Abstract: A fluid discharge method and apparatus is provided. The fluid discharge apparatus includes a first structure defining a first duct therein, a second structure defining a second duct therein and a third structure defining a third duct therein. Conduits formed in the structures, accurately positioned during machining thereof, extend from openings towards the ducts. Fluid in the ducts is initially directed into the conduits and subsequently out of the openings towards a cutting area comprising portions of a cutting blade and a workpiece being processed by the cutting blade. The conduits are shaped for generating a nozzle-type flow therethrough for accurate directional control of fluid streams discharged from the conduits. A method of forming the fluid discharge apparatus is also provided.

Abstract: Apparatus for high speed grinding comprises a grinding wheel having a circumferential grinding surface, a machine for mounting and rotating the grinding wheel about the axis, a coolant supply system including a slot nozzle arranged to direct coolant fluid secantly to the grinding surface, the slot nozzle having an exit with an elongate axis and a short axis wherein the elongate axis is tilted relative to the axis of the grinding wheel.

Abstract: A battery-operated hand-held power tool (2), especially an angle grinder, comprises a housing base (4) accommodating the electromotive drive components and air inlet openings (10) supplying the electromotive drive components with a cooling air flow. In order to protect the electromotive components from dirt, the hand-held power tool is designed in such a manner that a filter element (20) is provided in the area of the air inlet openings (10) and keeps dust, especially magnetizable dust, away from the electromotive drive components. The filter element (20) is retained by a filter retaining part (12, 30) which can be attached to the exterior of the housing base (4). The filter retaining part (14, 30) can be elastically deformed to such an extent that it is slightly deformed, especially expanded, when attached to the housing base, and engages behind or snaps into an element on the housing base.

Abstract: A heat reducing slot that is part of a saw blade that includes tips that will house carbide or other tips that are to be attached through a torch or induction. Heat reducing slots repeat for each tip on the perimeter of a blade that will be treated with high heat. For each tip, there is a general area defined near the seat and groove of the tip. In this general area a slot is inserted that has the effect of reducing the amount of heat needed to be applied to the blade for the attachment of carbide or other tips.

Abstract: An improved slot for a circular saw blade that reduces thermal cracking that occurs during the use of the blade. The slot extends from the peripheral edge of the blade in a vertical direction toward the center of the blade. It has an initial channel that takes a slight curve as it extends toward the center of the blade, but remains in a substantially vertical orientation until it terminates in a curve that is convex when viewed from the peripheral edge toward the center hole. The curve extends in both directions away from the channel portion. The first curve extends at a length that is longer than the length of the second curve. The curve does not complete a circle, but resembles a circle that has had been snipped at one point and one side hangs down below the other. Each curve terminates in an aperture.

Abstract: A head for an orbital abrading machine comprising a housing, a shroud including inner and outer portions, defining a chamber between the inner and outer portions, a drive means for driving an abrading pad, the drive means at least partially enclosed by the housing and the shroud, wherein the drive means produces an exhaust which is directly vented into the chamber without leaving the head, and wherein the chamber includes at least one opening for directing the exhaust toward the abrading pad for cooling the pad with the exhaust.

Abstract: The present invention is a slicing method and a wire saw apparatus including winding a wire around a plurality of grooved rollers and pressing the wire against an ingot to be sliced into wafers while supplying a slurry for slicing to the grooved rollers and causing the wire to travel in a reciprocating direction, in which the ingot is sliced with controlling a temperature of the ingot by supplying a slurry for adjusting an ingot temperature to the ingot independently from the slurry for slicing while the slurry for adjusting an ingot temperature is supplied to the ingot only at the exit side of the wire caused to travel in the reciprocating direction. As a result, there is provided a method and a wire saw apparatus in which rapid cooling of an ingot especially in a time close to end of slicing of the ingot can be alleviated, consequently degradation of a nano-topography can be suppressed, and further high-quality wafers having a uniform thickness can be sliced when slicing the ingot by using a wire saw.

Abstract: An exemplary grinding device includes a fixed barrel, a rotatable barrel, a grinding plate, an actuator and a cleaning assembly. The fixed barrel defines a chamber and includes a number of inner sidewall substantially parallel to a central axis, each of which defines a holding groove for holding a workpiece. The rotatable barrel is received in the chamber and includes an outer side substantially parallel to the central axis and defines an installation groove. The grinding plate is installed in each of the installation grooves. The actuator is configured for driving the rotatable barrel to rotate and simultaneously move up and down in the first chamber, such that the grinding plates contact the workpieces and grind the workpieces. The cleaning assembly is situated under the fixed barrel for cleaning the workpieces.

Abstract: The present invention provides an abrasive wheel that comprises a ring-shaped abrasive surface and an integrally formed central portion. The ring-shaped abrasive surface has an outer peripheral edge and an inner peripheral edge. The integrally formed central portion comprises an attachment portion for attaching the abrasive wheel to a rotation source and a plurality of fan blades for directing air-flow over the ring-shaped abrasive surface. The plurality of fan blades are positioned radially inwardly of the inner peripheral edge of the ring-shaped abrasive surface.

Abstract: A heat dissipating architecture for a machine tool is provided. The machine tool includes an accommodating space, a tool shaft mounted in the accommodating space, a counter balancing mass having a first balancing portion and a second balancing portion mounted on the tool shaft for causing an eccentric rotation stroke of the tool shaft, and an inlet communicating with the accommodating space. The heat sink is mounted on the counter balancing mass. The heat sink includes a first blade portion corresponding to the first balancing portion, a second blade portion corresponding to the second balancing portion, and a linking portion for connecting the first and second blade portions, such that during the rotation stroke of the tool shaft, the heat sink inhales air via the inlet, transmit the air from the first blade portion to the second blade portion, and then exhausts the air from the second blade portion.

Abstract: An electric power tool is described, and which includes a housing in which a drive, a fan unit and an electronics device are accommodated, and wherein an air stream for cooling the drive to be generated with the aid of the fan unit through at least one air inlet opening and at least one air duct being formed within the housing, and wherein the air duct extends from the air inlet opening to the drive, and which allows a directed supply of air to flow to the drive, with the air inlet opening being arranged in an end region of the electric power tool.

Abstract: A dynamic pressure in the coolant supplied between a rotating grinding wheel and a rotating workpiece is released by making at least one of oblique grooves on the grinding wheel pass vertically through a contact surface on which a grinding surface of the grinding wheel contacts the workpiece. Where one and the other side intersection points are defined as intersection points at which both ends of each oblique groove respectively cross extension lines of one and the other side edges parallel to a grinding wheel circumferential direction of the contact surface, the other side intersection point of each oblique groove overlaps the one side intersection point of an oblique groove next to each such oblique groove by a predetermined overlap amount in the grinding wheel circumferential direction, and the length in the grinding wheel circumferential direction of the contact surface is made to be shorter than the overlap amount.

Abstract: An edge dressing grinder tool used for making a continuous straight, vertical edge on a concrete, natural stone or artificial stone slab used for a countertop or table. The tool includes a manually operated hand grinder with a perpendicularly aligned grinding disc or pad mounted on a drive shaft. Attached to the head of the grinder is a forward extending, longitudinally aligned bracket. Extending laterally from the bracket are two slide arms and an adjustment rod. Mounted on the distal ends of the slide arms is a guide plate with a low friction, sliding plate. Mounted along the rear edge of the guide plate are two, transversely aligned wheels that press against a raised edge formed on a rigid fence that is fixed in position on the top surface of the work piece and parallel to the edge. The end of the adjacent rod engages a nut assembly mounted on the slide plate that allows the distance between the grinder's head and the guide plate to be selectively adjusted.

Abstract: A device for abrasive machining, comprising a substantially cup shaped to rough rotatable around an axis and having an inner chamber and a disk-shaped to working element at its one axial end; and immovable holder attachable to a machine to and surrounding at least a portion of said working element at an opposite axial end at a distance therebetween so as to form a passage for passing a cooling liquid; and a helical guiding means provided in said passage so that during rotation of said tool inside said holder the cooling liquid is supplied through the substantially helical guide into said inner chamber of said tool toward said working element.

Abstract: A tool assembly for machining a bore. The tool assembly includes a cutting tool and a tool holder. The cutting tool has an abrasive grit disposed continuously around a circumference of the cutting tool. The tool holder has a first coolant passage and a secondary coolant passage that extends at an angle from the first coolant passage.

Abstract: A power tool includes an air introduction device that can introduce an external air into the casing and can produce a spiral flow of the air within the casing. A motor is disposed within the casing.

Abstract: Embodiments of the present invention relate to apparatus and method for improve uniformity of a polishing process. Embodiments of the present invention provide a heating mechanism configured to apply thermal energy to a perimeter of a substrate during polishing, or a cooling mechanism configured to cool a central region of the substrate during polishing, or a biased heating mechanism configured to create a temperature step differential on a given radius of a polishing pad.

Abstract: An eyeglass lens processing apparatus includes: a processing chamber for processing the lens; a grinding water supply unit which includes a first switch unit for turning on/off a supply of grinding water to a first nozzle for ejecting grinding water toward a processing point of the lens; a cleaning water supply unit which includes a second switch unit for turning on/off a supply of cleaning water to a second nozzle for ejecting cleaning water for cleaning processing refuse of the lens scattered in the processing chamber. According to a selection signal indicating a material of the lens being plastic, the control unit controls the first switch unit to turn on the supply of the grinding water in whole processing processes, and controls the second switch unit to turn off the supply of the cleaning water in the whole processing processes.

Abstract: The invention relates to a machine tool, particularly a hand machine tool, which comprises a driving motor and an air guide element, which is disposed in the housing of the machine tool and conducts an air current passing over the driving motor to the outside. The air guide element comprises a functional section, which forms a part of the outer lateral surface of the machine tool.

Abstract: A rotatable abrasive lapper machine platen assembly is attached to a lapper machine frame. The assembly has at least: a) a circular-shaped rotatable horizontal platen having i) a front surface and ii) a back surface; b) the circular platen having a platen radius, a platen outer circumference and a platen outer periphery; c) the circular platen front surface having an outer annular planar portion where the platen outer annular planar portion extends radially to the circular platen outer circumference; and d) a flexible abrasive disk secured in conformable flat contact with the circular platen front surface outer annular planar portion wherein the abrasive disk is positioned concentric with the circular platen.

Abstract: A mount is disclosed for mounting a blade on a rotary spindle of a power tool. The spindle has an axial bore through which a cooling fluid may flow. The mount includes a disk configured for directing cooling fluid outward in a generally radial direction with respect to the axis of spindle when the blade is mounted face-to-face with an outer face of the disk. An adapter is also disclosed that can be used with a conventional blade mount for achieving the same result.

Abstract: A head for an orbital abrading machine comprising a housing, a shroud including inner and outer portions, defining a chamber between the inner and outer portions, a drive means for driving an abrading pad, the drive means at least partially enclosed by the housing and the shroud, wherein the drive means produces an exhaust which is directly vented into the chamber without leaving the head, and wherein the chamber includes at least one opening for directing the exhaust toward the abrading pad for cooling the pad with the exhaust.