Abstract: Quality control attachment adapted to be fitted onto a threaded depth control bar of a drill press machine includes a sleeve having an axial opening for fitting onto the control bar and being longitudinally movable relative to the bar. The sleeve carries a pawl and an elastic O-ring which urges an edge portion of the pawl into engagement with the threads of the control bar for enabling one-way movement of the control bar downwardly through the sleeve. An actuator pin is slidably disposed in a bore which extends through the sleeve and is movable downwardly in response to contact with a stop-nut disposed on the bar when the drill press has advanced to a preset depth represented by the position of the stop-nut.

Abstract: A device for changing the stroke of a caulking machine having a table on which is placed an article having a plurality of rivet shanks, and a rivet head forming tool. The table is adapted to be moved back and forth and right and left to bring the rivet shanks into the position right under the rivet head forming tool one after another. The rivet head forming tool is driven by a motor and moved up and down by a cylinder to form a rivet head at the top of each rivet shank. The device for changing stroke has a plate member movable up and down together with the rivet head forming tool and stopper pins having their top ends secured to the plate member. An annular plate is mounted outside a rotary shaft of the rivet head forming tool so as to be freely rotatable at a predetermined position. A plurality of pins having lengths corresponding to the lengths of the rivet shanks of the article are secured at equal intervals to the annular plate to extend upright.

Abstract: A quick adjust depth gage includes a handle-clamp assembly wherein the clamp includes an opening in which a cylindrical shaft with suitable depth measurement markings thereon is received. Turning the handle on the clamp enables the gage to be set to the desired depth.

Abstract: Barrel casing attached to the housing of a hand-held drill. A retractable guide arm is cantilevered from one end of the barrel casing. The cantilevered end of the guide arm has a passageway for the drill bit, and thereby guides it. A rate limiter is attached to the other end of the barrel casing and in axial alignment with it. On the inside of the barrel casing, the rate limiter is connected to the guide arm by abutment.

Abstract: In a drilling device, a holder is provided that is displaceable with respect to a foot in a feed direction. A drilling machine tool is carried by the holder. An electromotor provides a feed drive for driving the holder in the feed direction. The drilling machine tool and/or the holder are displaceable relative to the feed drive in an opposite direction to the feed direction by overcoming a counterforce. A switching element monitors the relative displacement and enables a signal to be derived for stopping the feed drive if a predetermined value of counterforce is exceeded. Motor current is limited to a predetermined maximum value during operation of the device.

Abstract: A positive feed drill and method of operation is disclosed for drilling through a workpiece consisting of a softer overlay material on a harder base material. The positive feed drill includes a high-speed air motor and a low-speed air motor and will start and drill through the softer overlay material at the high speed but will shift to the low speed when the drill senses that the thrust on the drill bit has increased because the drill bit has contacted the harder base material. After drilling through the harder base material, the drill bit will shift to the high speed because the drill senses that the thrust on the drill bit has decreased. The drill will retract from the workpiece at high speed and will shut off. Control apparatus is provided to control the flow of air to the high-speed and low-speed air motors. Sensing apparatus senses the thrust on the drill bit and sends a signal to the control apparatus to switch between the air motors.

Abstract: A positive feed drill having a spindle drive gear train and a spindle feed gear train coupled to the drive gear train is provided with means for uncoupling the feed coupling gear from the drive coupling gear, and locking the feed coupling gear when the spindle has been fed a predetermined extent, thereby placing the drill in retract mode, and for unlocking the feed coupling gear, once the spindle is retracted, without recoupling it to the drive gear train, thereby placing the feed gear train in an idle mode until the aforesaid uncoupling means is manually reset. The drill is further provided with a rapid advance coupling gear keyed to drive a shaft which turns the drive coupling gear and with a rapid advance idle gear meshed with the rapid advance coupling gear. The gear ratio of the rapid advance coupling gear to the rapid advance idle gear is selected to be greater than the gear ratio of the feed coupling gear to the normal idle feed gear.

Abstract: A drill for drilling holes in masonry and comprising a depth stop mounted on the drill shank and formed as a resilient anti-vibration element.

Abstract: A drilling guide for providing stability, direction, force and depth control for precise drilling comprises a hollow shaft attached to drill shaft casing, a telescopic housing connected to hollow shaft with a close coil spring, a depth measuring scale and a set of locknuts as depth controlling device. The threaded portion of hollow shaft provides means for depth measuring and controlling surface and nonthreaded portion and outward flange provides means for direction guidance for the housing. The housing which could protect adjacent objects from drilling relatively moves upwardly during downward movement of hollow shaft and stops at where locknuts are located. The housing comprises a serrated edge for aiding stability and vented holes for exiting drilling byproduct. The close coil spring can provide consistent resistance to prevent unexpected plunging of drill bit and can bring the drill bit back to the original position following the same path of drilling.

Abstract: A position indicating mechanism for a milling machine or the like includes a position indicator having a rail and a position indicating scale slidably mounted thereto to provide a digital readout of the position of the scale along the length of the rail. A rail mounting bracket is adapted for mounting to the milling machine and for affixing the rail to the milling machine. A scale mounting plate is adapted for connection to the slidable scale, and also for interconnection with a movable collar of the milling machine which moves synchronously with movement of the work-performing component of the machine.

Abstract: A drill spindle (62) is carried by the forward end of an elongated gear housing (12, 14). A parallel drive shaft (84) is carried by the housing (12, 14) rearwardly of the spindle (62). A parallel lead screw (92) is positioned between the spindle (62) and drive shaft (84) and is attached to a workpiece-engaging foot (20). A plurality of gears transmit rotation of the drive shaft (84) to the spindle (62) and lead screw (92). Two leader pins (182) are attached to the foot (20) and engaged by bearings (186) carried by the housing (12, 14) to slide freely relative thereto and to provide stiffness between the housing (12, 14) and the foot (20). The leader pins are spaced laterally and rearwardly from the drive shaft (84). A fluid activated pusher member (30) cooperates with the foot (20) to wedge the forward end of the drill (10) in a recessed work area. A fluid operated dog clutch (124, 132) engages rotation of the lead screw (92).

Abstract: An adjustable stop member, comprises three parts which are mounted in longitudinal alignment, with the overall length of the aligned parts being adjustable. The first part is an elongate cylindrical member which has one closed end and a threaded, elongate bore extending inwardly from the other end. The second part is an elongate rod which has external threads for mutual engagement with the internal threads of the first part. The second part further has a flat extending longitudinally along the surface thereof and an index line extending longitudinally along the surface thereof and an index line extending along the length of the flat. The third part is a nut which is threaded on the second part. The nut can be tightened against the first part for firmly securing the parts together in a releasable, fixed position. The nut has equally spaced markings around its circumference which form a scale used with the index line on the second part in setting a desired overall length of the stop member.

Abstract: A numerically controlled machine for processing printed circuit boards, including a workpiece holder and at least one operating unit that includes a motor arbor with an exchangeable tool, and a feed mechanism with a drive motor, a control mechanism, and a first movement-measuring system. For each operating unit, there is provided a respective second movement-measuring system that is disposed thereon, and a respective reference measuring point on the workpiece holder, with the aid of which there can be measured a distance between a tip of the tool and an abutment surface of the operating unit that rests upon a workpiece during a processing operation. Prescribed drilling depths are correctable in the control mechanism of the feed mechanism via the measured distance value. This compensation of respective tolerance values is effected independently for each operating unit.

Abstract: A gear train between an input shaft and an output shaft includes an output gear, through which the output shaft moves axially, and an intermediate gear coaxial with a control shaft carrying an idler gear meshing with a nut threaded on the output shaft. The idler gear is axially movable between a first position in which a first dog clutch connects the idler gear to the intermediate gear so that the nut rotates relative to the output shaft, thereby causing the shaft to be fed to the right, and a second position in which the first dog clutch is disengaged and a second dog clutch connects the idler gear to a fixed member, thereby causing the rotating shaft to be fed to the left. A collar on the shaft acts on a lever which moves the control shaft together with the idler gear from the first position to an intermediate position.

Abstract: A power drill system the type having a positive drive spindle incorporating an adjustable depth control means mounted on the spindle. The depth control means includes a collar having an internal bore which is provided with threads conforming to the spindle threads. Thus, the collar may be longitudinally adjusted to a desired position on the spindle by rotating the collar relative to the spindle. The collar is provided with a plurality of circumferentially spaced detent chambers. A detent member is secured in at least one of the detent chambers and extends into at least one of the spindle grooves in order to key the collar against rotation relative to the spindle and thus fix the collar at the desired longitudinal location. A thrust bearing assembly is secured to the collar in interposition between the collar and the stop shoulder. Upon contact of the depth sensing means with the stop shoulder, the thrust bearing assembly permits relative rotational movement between the collar and the stop shoulder.

Abstract: A threading attachment is provided in the tooling area of a multiple spindle machine tool, wherein the tap holder is rotated by a motor which has an infinitely variable speed within a given range and includes a first speed for advance movements to tap workpieces. This advance movement is provided by a motive power unit to move the tap holder in the advance movement and also in a retract movement at the completion of tapping. The motor has a second variable speed condition to back the tap out of the workpiece. This threading attachment is modular in construction to permit it to be physically mounted in any of the spindle positions of the multiple spindle machine tool and to be capable of being utilized with machine tools of different frame sizes. The foregoing abstract is merely a resume of one general application, is not a complete discussion of all principles of operation or applications, and is not to be construed as a limitation on the scope of the claimed subject matter.

Abstract: A boring apparatus has a rotary member rotated by a motor, a transmission shaft transmitting its rotation to an electric drill by means of a rotation transmission mechanism for reciprocally moving the electric drill on the frame of the apparatus. The transmission shaft is selectively connected directly to the rotary member and connected operatively thereto through a coupling which is rotated reversely to the rotary member through a reduction mechanism and is designed to be disengaged from the transmission shaft when the shaft is directly connected to the rotary member and to be engaged with the shaft when the shaft is not directly connected to the roatary member. The apparatus has a selecting member which directly connects the shaft to the rotary member and disengages the coupling from the sahft.

Abstract: A drilling machine comprises an electric drill having a drill motor for rotating an annular drilling tool and a feed control motor for moving the annular drilling tool forward and backward with respect to a workpiece, both connected to an AC power source, and an electromagnetic base for fixing the electric drill on an object to be drilled.

Abstract: Disclosed is a quick-change nosepiece (10) for a power drill (27) capable of telescoping by very small increments in the longitudinal direction, of angular or rotational displacement, and of quick and easy engagement and disengagement so as to provide access to the drill bit (29). Alternatively, a nosepiece (10) may be changed with one of greater or lesser length to correspond to the length of the drill bit (29) as the bit is changed.

Abstract: A thread cutting apparatus and method are disclosed for the formation of tapered threads on the end of an elongated reinforcing bar of the type used in concrete structures. The apparatus includes a cutting head assembly having tool holder arms that are cantilevered outwardly from a face or barrier surface to effect cutting of the threads outwardly of the barrier so as to protect the guideways and cutting displacement structure control structure from chips and debris. The apparatus includes positive lead control for the thread cutting chasers, a rigid clamping structure for the bar and a fluid control assembly. The fluid control assembly is capable of positioning the cutting head and housing for one or a multiple number of frusto-conical cuts of predetermined depth to permit the simultaneous formation of threads and removal of material from the reinforcing bar end.

Abstract: A power tool motor housing rotates a spindle assembly which moves axially within limits of adjusting nuts. A sensing sleeve maintains an axially fixed position with respect to the drive housing and thus with respect to a depth adjustment for controlling axial movement of the spindle. A foot piece moves along the sleeve as an adjusting nut is rotated on the sleeve to adjust stand off without changing preset depth of cut. A swivel assembly connects the sensing sleeve to the power housing so that the power housing may be rotated or indexed without changing the distance between the sensing sleeve and the depth adjustment.

Abstract: The automatic feed drill includes a spindle mounted therein for rotating in reciprocating movement. The spindle is rotated by spindle rotation gear that is engaged with the main drive gear which is ultimately driven by an air motor or the like. The feed and retraction movement (reciprocation) is caused by a spindle feed gear that is threaded onto the spindle. The spindle feed gear is engaged with a feed gear which, during feed movement, is driven by the main drive gear, and during retraction movement, is shifted into a position wherein the feed gear is prevented from rotating. The spindle also carries a collar or other abutment that engages a shift lever at the end of the feed movement. The shift lever is moved by the collar, and, due to its interconnection with the feed gear, moves the feed gear out of engagement with the main drive gear and into the position wherein it is prevented from rotating. The apparatus also includes a yieldable stop device that holds the feed gear stopped during retraction movement.

Abstract: A cartridge trimming apparatus of the mini-lathe variety. A removable stop member is provided between the cutter shaft holder and the cutter shaft handle. The stop member includes a length-adjusting screw that permits adjustment of the overall length of the stop member to accommodate a specific caliber of cartridge case. A lock nut locks the stop member to that specific caliber of cartridge. Different stop members are adjusted and locked to different calibers of cartridges. A mounting clip allows easy, rapid changing of the stop member on the trimmer to allow the user to quickly adapt the trimmer to the various calibers of cartridge cases.

Abstract: The automatic feed drill includes a spindle mounted therein for rotating in reciprocating movement. The spindle is rotated by spindle rotation gear that is engaged with the main drive gear which is ultimately driven by an air motor or the like. The feed and retraction movement (reciprocation) is caused by a spindle feed gear that is threaded onto the spindle. The spindle feed gear is engaged with a feed gear which, during feed movement, is driven by the main drive gear, and during retraction movement, is shifted into a position wherein the feed gear is prevented from rotating. The spindle also carries a collar or other abutment that engages a shift lever at the end of the feed movement. The shift lever is moved by the collar, and, due to its interconnection with the feed gear, moves the feed gear out of engagement with the main drive gear and into the position wherein it is prevented from rotating. The apparatus also includes a yieldable stop device that holds the feed gear stopped during retraction movement.

Abstract: The spindle can be rotated by way of a set wheel, and thus displaced within the spindle guide. At the end of this displacement, the spindle butts against one of the set screws of a turret stop provided on the rest plate. The spindle can be locked to the respective set screw by way of a swing extension. The spindle may be hollow to pass therethrough a tool and finely adjust the set screw already locked to the spindle.

Abstract: The improved dwell and depth attachment includes an elongate housing that is attached to a drill motor and has an output shaft that is movable longitudinally and rotatably in the housing for rotating a drill bit. A drive spindle is connected with the output shaft and extends through the housing. An elongated sleeve encircles the spindle and has an end that is engageable with the work piece. An adjustable depth control located within the housing is connected for movement with the spindle. A first portion of the control includes a threaded interior and has ten circumferentially spaced, radially extending holes therein. The control also includes a second portion that has a threaded exterior mating with the first portion and has ten slots equally spaced about the exterior. A stop screw or the like is removably located in one of the radial extending holes in engagement with the second portion.

Abstract: A positive feed drill having a spindle drive gear train and a spindle feed gear train, coupled to the drive gear train by side teeth on respective drive and feed coupling gears mounted on a common shaft, is provided with a spring between the feed coupling gear and a housing to bias the feed coupling gear against the drive coupling gear to feed the spindle forward as it drills. A positive stop prevents the spindle from feeding beyond a predetermined point, thus causing the feed coupling gear to be driven by the spindle. A slope on the faces of the side teeth engaging the drive and coupling gears in order to allow the feed coupling gear to ratchet over the drive coupling gear when the spindle feed reaches the positive stop.

Abstract: A nosepiece for a drill motor. The nosepiece is adjustable to allow the nosepiece length to be changed rapidly to compensate for different drill lengths. The nosepiece is threaded to mate with threads on the drill motor housing and can be adjusted longitudinally along the motor center line axis. When the nosepiece is threaded along the housing to a desired location it is locked in place by a locking ring keyed to the nosepiece and fixed in position on the drill motor housing by a hand adjustable set screw.

Abstract: A feed rate attachment for a drilling tool or the like. The drilling tool is equipped with a piston attached thereto operating within a cylinder positioned against the work-piece. A hydraulic damper is utilized to linearly resist the movement of the drilling tool attached piston relative to the cylinder.

Abstract: An improved hydraulic stop for use with drilling and countersinking tools. The stop limits the penetration of the tool into the workpiece by dwelling at a pre-set depth while the machine spindle continues to travel (feed) through a hydraulic override system.A safety relief valve, pre-set to a safe load, will permit the device to collapse or override if the hydraulic or mechanical override system should fail.

Abstract: The depth control assembly for attachment at one end to a machine tool and at the other end to a drill plate of a jig having selected guide holes positioned over points to be drilled in a production part. The depth control assembly is a spring-loaded adaptor which spaces the drill a constant distance from the production part, regardless of differences in distance between the face of the drill plate and the production part. Through the use of the depth control assembly, an operator can drill holes of a constant depth in the production part without taking separate measurements and making new depth adjustments at each hole location.

Abstract: The improved dwell and depth attachment includes an elongate housing that is attached to a drill motor and has an output shaft that is movable longitudinally and rotatably in the housing for rotating a drill bit. A drive spindle is connected with the output shaft and extends through the housing. An elongated sleeve encircles the spindle and has an end that is engageable with the work piece. An adjustable depth control located within the housing is connected for movement with the spindle. A first portion of the control includes a threaded interior and has ten circumferentially spaced, radially extending holes therein. The control also includes a second portion that has a threaded exterior mating with the first portion and has ten slots equally spaced about the exterior. The threads are selected to be loose fitting so that the portions of the control can "float" relative to each other.

Abstract: A measuring attachment is shown for use on a lathe or other machine tool which includes a pair of parallel bars or slots, one associated with the saddle of the lathe and the other associated with the cross slide. Mounted upon the parallel bars (or within the slots) are a pair of blocks each including a latching arm that latches each block to one bar or the other. A single stop is mounted on the first block, while a group of several stops may be mounted upon the second block. When an outer diameter is to be cut, the several stops may be attached to the bar mounted upon the radially fixed saddle. In this arrangement, the shortest of the several stops is used as the center line reference against which the single stop engages. The longest of the several stops provides the reference for the first outer diameter cut. When an inner diameter cut is to be made, the block mounting the several stops may be attached to the bar which is mounted upon the cross slide.

Abstract: A drilling machine of the woodpecker type employs a spindle carrying a drill. The spindle is mounted for rotation in a housing having an attached feed screw and those members form an assembly that can be axially moved while the spindle rotates to enable the drill to be fed toward and retracted away from the work. The feed screw is engaged by a nut whose position is controlled by a rapid traverse mechanism which can rapidly retract the spindle away from the work and can rapidly advance the spindle toward the work. The rapid traverse mechanism holds the nut fixed in position in the interval between rapid advance and rapid retraction. A peck feed machanism is connected to the feed screw and repititively feeds the spindle toward the work by causing the feed screw to progressively advance into the nut in the intervals when the nut is fixed in position. A hitch feed is coupled to the feed screw and acts to prevent the drill from bottoming in the hole on rapid advance.

Abstract: A positive feed drill has an elongated spindle mounted for reversible longitudinal motion in a drill housing. The spindle has a hexagonal cross-section with the apices of the hexagon being threaded. A toothed drive gear having a hexagonal aperture centrally thereof has a close sliding fit with the spindle for imparting rotation thereto. A feed gear threadedly engages the spindle apices and is selectively rotated at a different rotational speed than the drive gear to correspondingly longitudinally advance and retract the spindle. A pneumatic circuit provides completely automatic drilling to an adjustable depth and a positive retraction of the spindle. This circuit is novel in that it is contained internally within certain of the drill frame members.

Abstract: A machine tool control system adapted to provide automatic depth compensation for a cutting tool which controls the position of the tool in relation to a workpiece to hold the predetermined depth of a sleeve bore surface.

Abstract: A multi-stop depth control for a milling machine is disclosed which includes a fixed member connected to the milling machine frame having a rotatable wheel mounted thereon. The wheel carries a plurality of stop posts each with a stop member. Each stop is engageable with a through bore of a movable part of the milling machine which is connected to the movable quill thereof. By rotating a selected one of the posts into alignment with the movable part of the milling machine a selected depth of movement for the movable part of the milling machine is established.

Abstract: A dwell assembly back spotface for use with a reverse feed drill to provide an accurate depth of cut together with cutter dwell to insure a clean hole.

Abstract: An apparatus for penetrating a casing wall, particularly the casing wall of a detonating or firing mechanism, when disarming an undetonated explosive object, such as a live bomb, includes a drill unit driven by an electric motor and carrier means for carrying the drill unit in substantially any selected position relative to said explosive object. A feed means is arranged for moving in a controllable fashion at least a part of the drill unit holding the drill in the axial direction of said drill, and means are provided for detecting a decrease in the drill torque responsive to penetration of the drill through said wall.

Abstract: In a positive feed power drill having a spindle drive gear train and a spindle feed gear train, and having hydraulic (air) means for actuating a piston to disengage the feed gear train for automatic retraction of the spindle, provision is made for field alteration of a valve in the hydraulic system, and associated actuating mechanism, to automatically reverse the positive feed when the spindle has been driven either (1) a predetermined extent set by a nut on the spindle which engages an arm over a valve stem and pushes the valve stem to a reversing position or (2) to a predetermined stop when countersinking, at which time the spindle stops advancing, thereby causing the spindle feed gear to have a tendency to move upwardly in the spindle actuator housing.

Abstract: A machining center convertible between micro and macro machining operations with elimination of reactive spring back infeed pressures in the macro machining mode.

Abstract: A drilling machine of the woodpecker type employs a spindle carrying a drill. The spindle is mounted for rotation in a housing having an attached feed screw and those members form an assembly that can be axially moved while the spindle rotates to enable the drill to be fed toward and retracted away from the work. The feed screw is engaged by a nut whose position is controlled by a rapid traverse mecahnism which can rapidly retract the spindle away from the work and can rapidly advance the spindle toward the work. The rapid traverse mechanism holds the nut fixed in position in the interval between rapid advance and rapid retraction. A peck feed mechanism is connected to the feed screw and repetitively feeds the spindle toward the work by causing the feed screw to progressively advance into the nut in the intervals when the nut is fixed in position. A hitch feed is coupled to the feed screw and acts to prevent the drill from bottoming in the hole on rapid advance.

Abstract: A depth stop for a drilling tool comprises a rod 12 mounted on the tool body for sliding movement in directions parallel to the drilling movement, and a locking lever 15 pivotally mounted about a pivot boss 16 which projects at a substantially right angle to but is offset from the rod. The rod, extends through an aperture in the upper part 18 of the lever which aperture provides a radical clearance for the rod, and a spring 19 biases the lever so as to bring a peripheral edge or opposite peripheral edges of an aperture through the lever into frictional engagement with the rod and the biasing direction is the same as the direction in which the rod tends to move when it comes into abutment with a workpiece. The rod can be released by manually swivelling the lever against the spring force. The rod 12 may have a knurled surface 14 so as to provide substantially a mechanical lock with the co-operating peripheral edge of the lever aperture.

Abstract: A pin chuck press having means for adjusting the rest position of the pin inserting means up or down with respect to a work piece supporting base so that the inserting means will be able to place pins in the cooperating holes in work pieces of different vertical dimensions.

Abstract: A limit switch gauge positioner for a machine ram supporting a forming tool or the like. The ram, supported for reciprocal movement relative to a head, has a lineal distance gauging rod thereon formed with a plurality of longitudinally graduated reference indents. The rod has a body member slidable thereon including a detent coupling plunger adapted for engaging a selected one of the indents allowing an operator to initially locate the body member relative to the ram. A micrometer is supported on the body member with its spindle being settable at graduations along the spindle axis parallel to the path of travel of the ram. The head supports a housing including a microswitch with its actuator aligned on the spindle axis. An operating member is pivoted on the housing intermediate the switch actuator and spindle and gravitationally biases an arm section into arresting contact with the actuator in its extended switch closed position.

Abstract: This invention relates to an improvement in a hand drill with a pneumatically-hydraulically controlled advance and including a housing, a drilling drive unit adapted to be powered by compressed air and being displaceably guided in said housing by a piston and cylinder, and further including hydraulic lines, and control valves, the improvement comprising a rotatable support sleeve means secured to said housing and adapted to rest on the surface of a workpiece and surround a drill bit, said piston being a double-faced hollow advance piston means mounted in said cylinder so as to divide said cylinder into two chambers, one chamber together with one face of the advance piston means being adapted to be acted on by the compressed air, and the other chamber being adapted to be filled with hydraulic fluid and pressure-loaded by the other face of the advance piston means, said latter chamber communicating through hydraulic line means and a throttling back-pressure valve means with a cylinder means having a compensatin

Abstract: A plunge type router is disclosed which includes an improved depth lock system operative to exert a clamping force directly on the motor housing and which distributes the clamping force over a substantial surface area thereof whereby the motor housing may be securely retained in position without damaging or distorting the housing. An adjustable depth stop system is also provided which provides a positive, easily, accurately adjustable stop member engageable by a portion of the motor housing and an associated rack and pinion adjustment assembly operative to accurately locate the stop member so as to provide positive control of the depth of cut.

Abstract: An improved power drill having means for sensing when the drill bit has penetrated through the workpiece and for then retracting the drill bit from the workpiece. An electrical signal responsive to the axial force between the drill and the drill bit is used to sense when the drill bit pierces the workpiece. A sudden decrease in the axial force triggers a mechanism for retracting the drill bit from the workpiece. Means are included to detect broken bits, missing bits and previously drilled holes.

Abstract: A tool guide for providing a stationary support for a portable power tool such as an electric drill. When the lower portion of the device is clamped between the vise jaws of a portable workbench and vise, an electric drill slidably mounted on the device may be used to drill either perpendicular or angular holes in a workpiece positioned on top of the vise jaws. An adjustable depth stop operatively associated with the slideway of the device provides accurate depth control. The device may also be used independently in order to add accuracy to free hand drilling for both perpendicular and angular holes.

Abstract: An automatic hydraulic stop for use with a numerical control machine and cutting tool. The stop senses the distance to a work piece, limits the depth of penetration of the tool into a work piece and provides protection for inadvertent travel of spindle of the numerical control machine beyond a projected point.