Abstract: A drill rig for drilling access holes in drill resistant materials, such as those used to construct safes or other secure containers. The drill rig includes a drill bit holding and advancing mechanism having enclosed threaded members for allowing incremental, even pressure to be applied during a drilling operation while preventing burrs and chips from becoming lodged within the threads. A sliding connection is provided between stationary frame structure of the rig and the drill bit holding and advancing mechanism. The connection includes a spring loaded, quick-release mechanism for allowing quick detachment of the drill bit holding and advancing mechanism from the frame structure at the end of a drilling operation or as needed to replace the drill bit.

Abstract: A core drill of dry type used for drilling through concrete structure or the like. A main shaft 23 rotatably driven by a motor 33 with a fan 32 is provided with a rubber ring 27 for allowing axial vibration of the shaft, and loosely supported by bearings 25 and 26 with a clearance between them so that it can be slightly tilted in the lateral and transverse directions. During drilling, a spacing between a diamond tip in a leading end of the core bit and a concrete structure or the like is changed as the core bit is moved in the vertical direction and tilted in the lateral and transverse direction, and chips produced by the drilling operation are efficiently discharged by injecting air from the fan 32 through an axial bore 22 in the shaft 23.

Abstract: A magnetic based drill assembly comprising a support platform mounted to the magnetic base for attachment to a work piece includes a feed mechanism operatively connected to the platform for rectilinear movement between a fully retracted position and a fully extended position. The feed mechanism includes a splined collar slidably mounted to the splined arbor for movement relative to the splined arbor and for rotatably supporting a drive tool. The motor is mounted in a stationary position offset and substantially parallel to the feed mechanism to reduce overall height and weight of the drill assembly. As the splined arbor is located within a cylindrical feed arbor a liquid coolant can be directly injected on the drill tool and workpiece during operation of the drill assembly. Further, an electrical feed rate monitor provides a signal to the user to indicate the optimal feed rate of the drill tool.

Abstract: A suction grip for holding a pneumatic power tool to the surface of sheet material for drilling and counterboring holes contains a plate and a releasibly fastened cylindrical member. The plate contains a shallow region on a front face that abuts the work surface and serves as a vacuum region. The cylindrical member contains a hollow passage that receives, alternately, an alignment tool to center that passage over a locator hole in the worked material and to support a self collating pneumatic drill for drilling the worked material. A collection of collars which may be interchanged on the plate serves as a kit, permitting use with different drills.

Abstract: In a preferred embodiment the core drilling rig of the present invention includes a base, a vertically extending mast, a movable carriage mounted on the mast, an electric powered motor for rotatably driving a core drill bit, and a control system for controlling the supply of electric power to the drive motor. The control system includes a motion sensitive device for detecting the unwanted movement of the base and suspending the supply of electric power to the motor.

Abstract: Disclosed herein is a clamping device comprising a workpiece-engaging portion including a workpiece-engaging surface; sealing means for sealing the workpiece-engaging portion with the workpiece; the sealing means including a first resilient member arranged to seal between the workpiece-engaging surface and the workpiece, wherein the sealing means, the workpiece-engaging portion and the workpiece collectively form a first chamber; vacuum supply means for supplying a vacuum to the first chamber to draw together the workpiece and the workpiece-engaging portion; and pressure supply means for applying a pressure to the first resilient member to force the first resilient member against the workpiece-engaging portion and the workpiece. Also disclosed is a method for clamping a workpiece to a processing machine as well as a workpiece processing machine incorporating the clamping device.

Abstract: A seam tracking robotic drilling machine (10) is disclosed which is capable of moving a drill head along the seam (12) between abutting skin panels (16, 18) to drill a plurality of precisely positioned holes (18) through the panel. The machine (10) includes a perimeter support frame (20) which mounts a platform (36) for rotation about an axis (38) generally perpendicular the panels to be drilled. The platform supports a carriage (48) for movement along an axis 50 parallel the surface of the panels and in the direction of the seam while the carriage (48) supports an inner carriage (62) for movement along axis 60 perpendicular thereto. A drill head (74) is mounted on the inner carriage (62). A series of variable height vacuum cup assemblies (22-28) support the perimeter support frame (20). A similar series of variable height vacuum cup assemblies (66-72) support the inner carriage (62).

Abstract: A magnetically attachable, portable, adjustable, and collapsible safe drill mounting device to be used to align and hold a power drill in precise position against a steel safe in a predetermined manner so that the safe can be drilled open. The device can be attached to any size safe rapidly, easily and is totally portable and collapsible. Magnetic mountings which provide a minimum of 1800 pounds of attachment force allow the device to be attached to the largest safes. Each magnetic attachment block is adapted with a cam or jack screw release for detachment from the safe.

Abstract: A drill and tap guide comprises a block having appreciable thickness and one or more guide holes therethrough. The guide holes are sized to suit different diameter taps and/or drills. The guide holes are perpendicular to the plane of a block first face. The first face of the drill and tap guide is placed on a flat surface of a workpiece. A drill or tap is inserted through the appropriate guide hole, which guides the drill or tap to remain perpendicular to the workpiece flat surface during a hand drilling or tapping operation. The block may have a circular or rectangular periphery. Different combinations of guide holes to suit different size drills, tap drills, and taps can be formed in the block. In all cases, the guide holes are located close to the block periphery. A magnet can be embedded in the block to aid in holding the block on ferrous workpieces.

Abstract: A portable electromagnetic drilling machine which is provided with an enclosed motor power control cord that connects the machine electrical control panel to a machine electric drive motor for a cutting tool spindle. The provision of an enclosed electric motor power control cord eliminates any wrongful or inadvertent lifting of the machine by said cord, and insures the lifting and carrying of the machine will be carried out by a handle on the machine housing.

Abstract: A manually positioned computer controlled drilling machine (10) is disclosed for drilling a hole (12) through a surface (14). The machine includes a base (16) which is supported on a counterbalanced suspension so that an operator can manually move and shift the machine on the surface to be drilled. Automatic adjustable legs (20-26) are biased outwardly from the base by low pressure air cylinders which allows the operator to tilt and move the base (16) relative to the surface (14). This allows the operator to position the drill bit (18) over the position where the hole is to be drilled and orient the drill bit perpendicular to the surface. Caliper brakes (38) are then activated to lock the legs in place. A number of suction cup assemblies (42-52) are then sequentially moved outward into contact with the surface. A suction foot (56) on each of the suction cup assemblies is adhered to the surface by a vacuum.

Abstract: A drill support having a base, and a body secured to and supported by the base. A saddle member is movably disposed on the body and a drill is removably disposed or secured to the saddle member in order to move up and down therewith.

Abstract: A device for preventing contamination of a clean room during a drilling or cutting operation. A box-like chamber is provided for containing a power driven tool such as a drill. One wall of the chamber includes an opening for access to the workpiece (e.g. a wall to be cut or drilled). Another wall includes an access port with a rubber glove for operating the power tool. A pigtail electrical outlet within the chamber provides electrical power to the tool. A similar chamber may be used on an opposite side of the wall being drilled in the event it must be kept clean also. Both chambers include a port for attachment to a vacuum source such as a conventional vacuum cleaner and a port for entry of air to divert debris away from the workpiece and into the vacuum cleaner. In another embodiment, a small enclosure is clamped to the body of a drill or similar tool. The enclosure includes a vacuum port for removal of the debris.

Abstract: Portable drilling apparatus provided with a support by means of which it can be secured to a work member and mounting means for a cutting tool including a mounting member having a vertically extending elongate part within which a drive spindle is rotatably mounted, the drive means including an elongate toothed gearwheel driven by a motor held in a fixed position in the support, a toothed gear carried by the drive spindle engaging the elongate gearwheel and sliding axially relative thereto.

Abstract: A portable workpiece-mounted machine tool such as a drill is provided with a permanent-electromagnet attaching unit which has its reversible permanent magnets alternating with nonreversible permanent magnets so that, when electric current is applied to the reversible magnets, they are subjected to polarity reversal which causes flux closure through a workpiece of the reversible and nonreversible magnets in the "on" position and causes flux closure between a reversible and nonreversible magnet in an "off" position.

Abstract: A reusable break-out support tool and method are provided for use in drilling, or the like, a workpiece. The tool employs a granulated media situated within a cylinder. When a workpiece is to be drilled, the cylinder with the granulated media is engaged with the side of the workpiece which will bear the exit opening of the hole to be drilled. The granulated media is pressurized whereby it forms a load bearing surface applied to the workpiece.

Abstract: A mobile power tool operating assembly for performing material treatment operations, such as drilling, has permanent magnet means to mount the power tool on a ferromagnetic workpiece, and release means to permit release of the magnet means for repositioning of the tool. The release means comprises a screw threaded jack which tilts the assembly so as to overcome the magnetic attraction. The tool can then be repositioned and lowered to its normal working attitude.

Abstract: Methods and apparatus for cutting a groove in a structure are disclosed. Large structures such as steam turbines have pumping grooves or similar features which may be machined using the simplified methods and apparatus disclosed. In a preferred embodiment, a milling head affixed to a magnet which may be selectively activated is provided. Additional clamping means are also provided which are affixed to the magnet and engage the structure to further affix and align the apparatus in place. The milling head is positioned at the location of the groove and held fast by the magnet; the additional clamping means ensure the apparatus stays in place while the groove is being cut. The apparatus disclosed may be operated by a single operator using conventional power sources and without the need for extensive set up, fixturing and the like normally associated with milling operations of this nature.

Abstract: A drill apparatus with an electromagnet base, which has an electric drill directed downwards, is provided with an electromagnet base having an electromagnet for attaching the apparatus to a to-be-worked object by magnetic force. The electric drill is rotated by a drill motor and moved by a feed motor towards the object. A Hall element is situated on the electromagnet base. Two comparators detects whether or not a Hall voltage output from the Hall element falls in a predetermined range of voltage values. When the Hall voltage does not fall in this range, a transistor is turned on. Consequently, a relay is operated, a contact is opened, and power supply to the drill motor and the feed motor is stopped.

Abstract: The states of contact switches are switched when a mode switch is turned on. If the drilling operation is effected by means of a drill motor in this state, an oscillation signal which is repeatedly set to "H" and "L" in a preset period corresponding to an output of an oscillator is supplied to the control terminal of a firing pulse generator. The firing pulse generator interrupts supply of the control signal to the control terminal of a triac in the above preset period based on the oscillation signal supplied to the control terminal thereof to interrupt supply of an AC power source from a commercial AC power source to a bridge-type rectifier so as to intermittently drive a feed motor which is energized by an output of the rectifier in the above preset period. As a result, the drill motor can be intermittently fed towards a to-be-worked object by means of the feed motor, and, when the feeding operation is interrupted, a cutting operation can be instantaneously stopped and swarf can be cut apart.

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 magnet base drill unit in which the driving of the drill motor and the feed motor of the magnet base drill unit is stopped by operation of the switch which operates on the instant when sliding has been produced in the magnet base drill unit, and the stopping thereof is maintained electrically or electronically. A mercury switch comprising a cylindrical body in which mercury is sealed, and a pair of contacts provided so as to project into the cavity of the cylindrical body, or a vibration switch comprising a fixed contact, and a vibration responsive contact placed by a spring means in proximity to the fixed contact is preferably used.

Abstract: A boring apparatus wherein the size in the axial direction of the shaft of the manual handle horizontally supported can be made small-sized. A clutch is composed of spherical bodies, a cylindrical body having formed therein hole portions for receiving the spherical bodies, spherical body pressing means for pressing the spherical bodies to the outside or inside of the cylindrical body, and an engagement member having recessed portions engaging with the spherical bodies which are projected to the outside or inside of the cylindrical body, and the boring apparatus is constructed by using the clutch.

Abstract: A controller for a magnetic base drill unit provided with a safety circuit which is constructed by connecting in series a relay provided with contacts for cutting the power supply to the drill motor and feed motor, a resistor and a diode. The relay is actuated when a voltage higher than the predetermined voltage to be applied to the feed motor in the hole cutting mode is applied to the feed motor during the hole cutting, thereby cutting the power supply to the drill and feed motors. The controller has a means for confirming the operation of the safety circuit which apply a test voltage higher than the maximum predetermined voltage to be applied during the hole cutting to the feed motor in the fall mode of the electric drill.

Abstract: The present invention discloses a torque restraining device to resist the lateral shifting or rotation of a self adhering drill unit due to the torque generated by the drill motor. The torque restraining device includes a penetrating member mounted on the bottom of the drill unit for penetrating the work surface to prevent rotation of the drill unit during use. The penetrating member is embedded by the action of the drill unit being pulled to the work surface when the mounting base of the drill unit is activated. In the preferred embodiments, a protective sleeve is reciprocally mounted about the penetrating member to encase the penetrating member to prevent damage when the base is not activated. Upon activating the base, the sleeve retracts to expose the penetrating member for penetration into the work surface.

Abstract: A portable apparatus including a four-legged support that is equipped with adjustable support bases. The apparatus also includes a centering mechanism that includes rotatable eccentric discs, and a modified rotating unit, the rotating arm of which is provided with an adjustment mechanism that is equipped with a sensing device, and with a tracing device that is equipped with various copying templates and is coupled with a machining or processing tool for machining the rim of a flanged, flat, dished semi-ellipsoidal head in preparation for a welding seam connection with a tubular member to produce a circular cylindrical reaction vessel. The apparatus is installed in the upwardly open head coaxial to the axis of the latter. During each rotation of the rotating arm, the machining tool experiences a feed movement and an adjustment movement that is corrected for the geometry of the workpiece or head.

Abstract: A high speed drilling system is disclosed for high speed drilling of very small holes in workpieces such as printed circuit boards. The X-Y positioning system includes air bearings to provide lift between the stationary guide beams, the crossbeam and the top table, and further includes a vacuum preloading apparatus for providing a preloading force between the table and the guide beam. The preload force dampens Z axis oscillations which can result in drill bit breakage. The top table is a lightweight honeycomb structure, whose effective rigidity is virtually that of the guide beam due to the vacuum preloading. The system includes pairs of spindles, one a conventional spindle for drilling holes larger than about 0.125 inches, and the other a high speed spindle for drilling holes in the range of about 0.003 to 0.125 inches. The high speed spindle includes a stationary spindle body carrying the stator of the rotary drive motor.

Abstract: The power tool has a magnetic base with superimposed permanent magnet assemblies. The upper assembly can be moved relative to the lower assembly to shunt or reinforce the magnetic field. When the sensing probe is pushed into the base the electric motor can be switched on to rotate a spindle on which a rotary cutting tool is axially mounted. The tool feed is controlled by a handle which can be mounted on either side of the tool housing. A coolant reservoir on the base has a hose connected to a pump which is connected to a manifold supplying coolant to the interior of the cutting tool. The cutting tool is biased upwardly and pinches off the coolant when the tool is raised from the work.

Abstract: An improved chip disposer which removes chips or iron chips produced from a machine tool by using magnetic force is disclosed.

Abstract: The power tool has a magnetic base with superposed permanent magnet assemblies. The upper assembly can be moved relative to the lower assembly to subtract from or reinforce the magnetic field. When the sensing probe is pushed into the base the electric motor can be switched on to rotate a spindle on which a rotary cutting tool is axially mounted. The tool feed is controlled by a handle which can be mounted on either side of the tool housing. A coolant reservoir on the base has a hose connected to a pump which is connected to a manifold supplying coolant to the center of the cutting tool. The cutting tool is biased upwardly and pinches off the coolant when the tool is raised from the work.

Abstract: Device (1) for facilitating the circulation of fluid coolant having, in compact form, a circulating pump (7), a settling cascade (17) and a negative-pressure pump (20) for suctioning a workpiece (54) onto a worktable (21). The transfer pump (7) and a negative-pressure pump (20) are connected to operate with one another in the coolant cycle and to prevent loss of coolant.

Abstract: A pin machining fixture 10 has a plurality of openings 25 extending through a body having exterior surfaces 11-16 that lie accurately in three pairs of parallel planes that intersect perpendicularly. Each of the through openings 25 has a location notch 26, and the apexes of location notches 26 are equally spaced apart and arranged in a plane parallel with a pair of exterior surfaces. Set screws 30 threaded into the body clamp a pin or work piece 20 in each of location notches 26 so that a portion of each pin 20 extends beyond one exterior surface for machining. An abutment key 40 is preferably adjustable within the exterior surfaces of fixture 10 for locating ends of a plurality of pins 20 to be clamped and machined.

Abstract: A device for boring tunnels to accommodate electrical cables or conduits in the thickness of an insulative material of a composite wall panel exhibiting a layer of this material covered on one or both sides with a rigid facing sheet made up of a mobile system and a positioning and guiding device for the mobile system. The mobile system incorporates a boring member mounted at the end of a flexible member, and the positioning and guiding device incorporates a removable support featuring means for attaching it to the or one facing sheet, in line with an opening formed in the latter, and a bent guide conduit adapted to be inserted into this opening. This conduit enables the boring and flexible members to penetrate into the insulative material parallel to the facing sheet, in the required direction and to the required distance.

Abstract: The power tool has a magnetic base with superposed permanent magnet assemblies. The upper assembly can be moved relative to the lower assembly to subtract from or reinforce the magnetic field. The upper assembly is somewhat shorter than the lower assembly so even when the upper assembly is positioned to shunt to subtract from the flux of the lower assembly there will be some magnetic flux attracting the base to a ferromagnetic material. When the sensing probe is pushed into the base the electric motor can be switched on to rotate a spindle on which a rotary cutting tool is axially mounted. The tool feed is controlled by a handle which can be mounted on either side of the tool housing.

Abstract: A drilling machine provided with an electromagnetic base comprises a first control system by which a warning device is actuated and/or a feed motor for automatically advancing an electric drill toward a workpiece is stopped when a load on the electric drill exceeds a prescribed first reference level while at work. A second control system further provided on the drilling machine is adapted to have the feed motor and/or the electric drill stopped when the load thereon is further increased and reaches a second reference level higher than the first reference level to assure high safety.

Abstract: A pair of support members and a pair of drilling units are mounted for reciprocal movement along a carriage. The support members secure to latch bolts on an elongated surface to be drilled. The drill units move along the carriage in both an X and Y direction to automatically drill holes in the surface. The drill units are then secured to latch bolts and the carriage with support members advanced on rollers located in the support members. The support members are secured to the next latch bolts and the process continued until holes are drilled throughout the length of the surface to be drilled.

Abstract: A magnetic base drilling machine includes a base having a magnet coil therein and a motor assembly mounted on the base for driving a rotary cutting tool. Electrical circuitry, including switches for applying power to the magnet coil, for reversing the direction of current to the magnet coil, and for controlling the current to the motor are provided for controlling the magnet coil and motor. A user-manipulatable control handle includes a multi-function control cam having cam surfaces that selectively control the switch that applies power to the magnet coil and which physically blocks operation of the motor switch until the magnet coil is energized. Conversely, the magnet coil cannot be de-energized until the motor switch is moved to its off position. If desired, the direction of the electrical current applied to the magnet coil can be reversed to assist in removing the base from a magnetized work surface.

Abstract: A material working tool 10 includes a device for working material 18 and a base 12 for supporting the device 18 for working the material. The base 12 includes a rigid member 26 and a cavity 54 defined in the rigid member 26 which is connected to a source of vacuum. A seal 66 is provided about the bottom surface 56 of the rigid member 26. The seal 66 is compressed as a vacuum is created in the cavity 54 so that the rigid member 26 comes into contact with the surface of the working material allowing for the accurate positioning of the material working tool 10 relative to the material to be worked.

Abstract: The invention concerns a portable electromagnetic pneumatic power drill. It may be used to make rivet or bolt holes in structural steel girders in guilding and bridge construction. The base of the drill stand is secured to the steel workpiece by electromagnetism. Exhaust air from the drill head cools the electromagnetic base as well as the bit and workpiece. Drill chips are diverted by the exhaust stream and deflected from the rack slide mechanism by a shield. This allows the slide to approach the base and workpiece very closely to improve steadiness and accuracy of drilling.

Abstract: A drill press and stand providing an improved apparatus for cutting holes in plate vitreous material. The drill press includes a drill motor, a drill tool attached to the drill motor for cutting through the work piece, and a motor support interconnecting to and supporting the drill motor on the stand. The stand includes a base which is attachable to the work surface by a large suction cup which is attached to the lower surface of the stand base. The stand also includes a collar integral to and generally perpendicular to the upper surface of the base into which a mating drill press standard, a part of the motor support may be inserted. The motor support also includes a positioning mechanism for longitudinally moving the drill motor along the standard and may include a biasing spring to counteract the weight of the motor, etc.

Abstract: A support frame having a face which may be positioned against a workpiece. A cutting arm is mounted for rotation relative to the axis of the frame in such a manner as to support a cutting tool which may be used to form a groove in a workpiece, such as a cylinder head. The cutting arm is supported in a rotating unit such that the depth of the tool and the radius of the groove may be precisely controlled. A crank is attached to the turning unit for positive rotation of the cutting tool. A plurality of locating, headed pins are mounted in the frame so that the heads are biased to positions beyond the workpiece-contact face of the frame. In the exemplary use of the tool to form a groove in a cylinder head, the pins may be precisely positioned so as to cooperate with stud bolt holes in the cylinder head in order to precisely locate the axis of the turning unit relative to the cylinder head.

Abstract: A stabilization device for the stand of a drilling machine which comprises a casing secured to the rear of the stand and having a vertical stepped opening and a horizontal opening intersecting the vertical opening at right angles, a punch received in the casing for upward and downward movement and having a pointed projection extending downwardly from the lower end of the punch, a compression spring received in the casing to normally bias the punch downwardly and a spring loaded stop normally biased into the horizontal opening.

Abstract: A cradle type adaptor for a magnet base drill which includes a box having a width slightly smaller than the width of the magnet base of the drill so that it can be assembled to the magnetic base by a clamping action. The box includes a pair of longitudinal sides and a pair of end sides. A front and rear vertically adjustable plate is adjustably mounted on the front and rear sides of the box. The front and rear adjustable plates have a V-slot in the lower ends thereof. The lower end of each of the longitudinal sides of the box is formed at an oblique angle so that the adjustable side plates may be adjustably mounted thereon for mounting the cradle pipe adaptor on a small size diameter pipe.

Abstract: This is a vacuum clamp for holding workpieces which assures that the workpiece is held without distortion. This is accomplished by providing a fixed support, with a convex surface, and a flexible seal around the fixed support so that when a vacuum is drawn within the seal the workpiece being held abuts the fixed support tangentially. The convex surface of the support does not force the workpiece to conform to the surface of the support as it would if the surface of the support were flat.

Abstract: Apparatus for accurately cutting pits or anomalies in steel pipe or plate stock to be used as a standard for calibrating magnetic flux leakage detection equipment used for testing for anomalies in such stock.

Abstract: An electromagnetic drill stand, of the type having a drill driven by an electric motor and mounted on a stand provided with an electromagnetic coil in the bottom of the stand to secure the stand to ferromagnetic material when the coil is energized, is provided with switch means preventing operation of the motor when the coil is not energized, said switch means being mounted in proximity to said coil and responsive to the magnetic flux of the coil for controlling the power supply to the motor and operative to interrupt the power supply in absence of a predetermined flux density.

Abstract: A magnet base drill unit having a finger thereon frictionally engaging the surface of the workpiece to which the base of the drill unit is magnetically adherred. The finger is movable in response to lifting or sliding of the energized magnet base from the support base of the workpiece to actuate a switch for de-energizing the drill motor. The unit also includes a pointed punch adjacent the rear end of the magnet base which can be in one form of the invention impacted into the workpiece support surface either by a manually operated lever or automatically whenever the drill spindle is retracted from the work to a position near the upper end of its stroke. A second punch may be located on the drill unit rearwardly of the automatically actuated punch. The second punch is arranged to be embedded into the support surface of the workpiece by a manually applied hammer blow.

Abstract: A centering pin for use in a machine tool work table of the type in which a workpiece fixture is supported on a film of pressurized air thereby enabling substantially friction free movement of the fixture on the table surface. The centering pin comprises an outer pin mounted within the table and projecting above the table upper surface, an inner pin received within the outer pin for reciprocal movement along a direction generally normal to the table surface, a hydraulic actuator for causing the inner pin to project above the outer pin at a first vertical position, and a spring for causing the inner pin to retract to a second vertical position below the first vertical position when the fluid actuator is deactivated. The fixture has one or more slots which ride over the outer pin and a plurality of holes within the slots which are adapted to be engaged by the inner pin when it is extended to its upper vertical position, thereby enabling controlled translation and rotation of the fixture on the table.

Abstract: A magnet base drill having a pair of plates formed of magnetic material removably mounted on either the side walls or the bottom face of the electromagnet forming the base of the drill and adjustable thereon to contact portions of a convex support surface spaced laterally outwardly from the central lonitudinal axis of the electromagnet when the latter is positioned on the support surface.

Abstract: The power tool has a magnetic base with superposed permanent magnet assemblies. The upper assembly can be moved relative to the lower assembly to subtract from or reinforce the magnetic field. The upper assembly is somewhat shorter than the lower assembly so even when the upper assembly is positioned to shunt to subtract from the flux of the lower assembly there will be some magnetic flux attracting the base to a ferromagnetic material. When the sensing probe is pushed into the base the electric motor can be switched on to rotate a spindle on which a rotary cutting tool is axially mounted. The tool feed is controlled by a handle which can be mounted on either side of the tool housing.