Abstract: Apparatus and method for installing a thermometer-receiving well within a fluid service pipe without interrupting the service in the pipe. A rod member is provided which defines a first end for removably receiving a cutting member for cutting through the fluid service pipe. The cutting member is then removed from the rod member and a connecting member is removably attached to the first end of the rod member in place of the cutting member. The connecting member is adapted to removably receive a thermometer well whereby the rod member can be used to cut through the fluid service pipe and to install the thermometer-receiving well within the fluid service pipe without interrupting the service in the pipe.

Abstract: A pressure foot for a machine for drilling a printed circuit board is supported to be slidable in an axial direction of a rotor shaft and is connected to a vacuum suction source. The pressure foot is adapted to depress the printed circuit board during a drilling operation. A first air pathway is formed from a first supply port formed in a side wall of the pressure foot to a plurality of first blow-out ports formed in a contact surface of the pressure foot with the printed circuit board. The first supply port is connected with a pressure air source. A second air pathway extends from a second supply port formed in the side wall to a plurality of second blow-out ports opened toward an interior of the pressure foot. The second air pathway is in communication with a supply source of a pressure air. Thus, the working time and cost are reduced.

Abstract: Boring apparatus includes a multiple start screw to secure a cutting piece to a boring bar. The multiple start screw prevents loosening of the cutting piece during use of the boring apparatus. The multiple start screw also enables easy changing of the cutting piece or repositioning of the cutting piece between periods of use of the apparatus.

Abstract: Apparatus and methods for alignment and mounting in position of a drill stem provided at one end with a cutting tool for use in removing coke from a coke drum. The drill stem is provided in the vicinity of the cutting tool with a drill stem guide carried on a slidably mounted plate. A flange on the drill stem is provided to prevent movement of the plate below a particular point. In a preferred embodiment, automatic clamping means are provided to attach the plate to an end flange on the coke drum when the drill stem guide has been lowered into the coke drum a sufficient distance so that the flange on the drill stem is disengaged from direct or indirect contact with the plate and/or connecting elements of the clamping means provided on an upper surface of the plate.

Abstract: A scroll compressor has a pair of mating scrolls that are disposed on parallel, eccentric axes, and each of these scrolls has a scroll plate and a spiral, involute wrap. The scrolls are driven so that one of them orbits about the axis of the other scroll while maintaining a fixed azimuthal relationship to it. The orbital motion causes a compressible fluid to enter at the periphery of the scrolls, and be carried and compressed by pockets formed between the mating wraps of these scrolls. The compressed gas is discharged out a discharge port at the center of one of the scrolls. The discharge port is bored diagonally into the scroll plate of the one scroll so that it has an elongated elliptical aperture at the center of the scroll plate. The port is machined into the scroll from the wrap side of the scroll. The enlarged size of the port aperture reduces the resistance to fluid flow and hence reduces the back pressure, thereby increasing the compressor efficiency.

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 modified concrete block, apparatus and method of manufacture for making the concrete block which includes a bored arch-shaped inspection hole formed through one side wall into one cavity of the concrete block. The inspection hole, used for inspecting reinforcements within the cavity prior to filling with concrete, is formed by the apparatus and in accordance with the method of manufacture by boring a circular hole through the side wall at an acute angle to the side wall in alignment with one cavity. The hole, generally equal in diameter to the length of the cavity, is offset so that it extends from through one edge margin of the side wall toward, but not to, the other side margin of the side wall.

Abstract: The method for constructing a panel assembly for a control unit comprises the steps of: creating a layout of the system to be controlled in a computer-aided-design system; providing in the layout circle areas for elements of the system to be illuminated to indicate a certain operating mode of the element; creating an overlay of centers for each of the circle areas in the computer-aided-design system; storing in a memory of the computer-aided-design system the layout of the system and a layout of the centers; printing a layout for an overlay of the system to be controlled to a desired scale; printing a layout of the centers to the desired scale; placing the layout of the centers adjacent an outer panel for marking centers thereon; drilling holes at the centers; placing the layout of centers over an inner panel for identifying the centers of the holes to be drilled; drilling holes in the inner panel; mounting light emitting means in the holes drilled in the inner panel; placing the overlay of the system on the

Abstract: A tool ball pad hole positioner is provided which includes first plate which is securely positionable with respect to a jig and has a large aperture therein; a second plate which is movable with respect to the first plate and has a small circular aperture therein overlying the large aperture; a target which is removably receivable within the small hole and able to be sighted by an optical device for determining the precise location of the target as well as the small aperture with respect to the precise location on the jig. The first plate is positively secured to the jig and the second plate is shifted and releasably clamped with respect to the first plate with respect to the first plate. Also disclosed is the method of drilling a hole in a tool ball pad with the tool ball pad hole positioner.

Abstract: A tool for removing seal plugs from a carburetor baseplate having a shaft and collet arrangement in which the shaft is formed at one end by a drill bit. The members are concentrically aligned within an outer holder member which also functions as a drill guide when the shaft-drill member is connected to a drill chuck and the drill bit end of the shaft is presented to the face cap of the seal plug. Once the end cap is removed by the drill bit end of the shaft member, the tool is then inserted as a unit through the cylindrical space defining the seal plug, and the seal plug is then removed in the conventional manner from the borehole without damaging the borehole or the baseplate.

Abstract: A rotatable cutter bit for drilling a hole in the hardplate of burglar-resistant safes includes an elongate hollow barrel having diamond grit bonded in a matrix to the periphery of the work-drilling end and a beeswax core in the hollow working end. A method for drilling hardplate includes the step of rotating a diamond-tipped drill bit in the hardplate in the presence of beeswax in the drilling interface.

Abstract: High pressure gas cutting process useful for drilling large numbers of holes in large surface area workpieces such as air frame components and the like. The procedure utilizes a cutting tool which has an internal fluid passageway extending through the shank portion thereof and terminating in at least one discharge port adjacent a cutting edge of the tool. As the cutting tool is rotated and advanced into the workpiece in the course of the cutting operation, a high pressure gas is supplied into the cutting tool passageway under an applied pressure of at least 500 psia. The gas, which may be an inert gas such as nitrogen, is discharged from the cutting port into the tool with an expansive cooling effect. The gas then flows outwardly through the hole and exits the hole with sufficient velocity to entrain and remove the drill cuttings from the hole. A liquid lubricant can be employed to prolong the life of the cutting tool.

Abstract: Disclosed is a turret punch press in which tap holder assemblies TA are incorporated into the press body through tool lifters. Each of the tap holder assemblies TA is composed of a tap holding mechanism, a tap feeding mechanism and a tabular workpiece clamping mechanism formed on the same axis. At the same time, transmission mechanisms DA for selectively transmitting the torque from the press body to the tap holding mechanisms are incorporated into the press body. With a punch press having this construction, tapping can be performed on the same axis as punching.

Abstract: A process for manufacturing a cylindrical body and a device for carrying out the process.With this process, in particular sample bodies of absorbents are obtained.The intention with this process is that the nature of the bodies taken is not falsified. A device, which allows this process to be carried out rationally, is to be specified. This is achieved by the fact that firstly a plane-parallel board (1) is cut out of the material, which board (1) is provided with a guide opening (4a). Inserted into the guide opening (4a) is a guide part (5) which guides a cutting element (9) concentrically to the said guide opening (4a), which cutting element (9) separates a sleeve-shaped body (13). This body (13) is then introduced into a measurement device.

Abstract: The invention is directed to a method and apparatus for selectively and simultaneously drilling a plurality of holes in thin panels such as printed circuit boards, while providing for automatic changing of the drill bits, individually or plurally, as required. A tray of drill bits is driveable in X and a row of vacuum pickers are driveable in Y, so that the various bit locations of the tray are addressable by such X-Y positioning, and selectable vacuum pickers are extensible and retractable so as to pick and place the drill bits at various matrix locations of the tray. The vacuum pickers also are extensible and retractable through corresponding tray openings in order to deliver replacement bits to, and retrieve used bits from, a flipper assembly associated with each drilling module.

Abstract: A method of machining a journal (14) on a lug (10) for a roller cutter drill bit in which the stand (22) holding the lug (10) is fixed and a cutting tool (26) is mounted on a holder ( 24) over the journal (14) for rotating about the journal (14). Two separate machining procedures for the journal (14) are provided with each machining procedure employing a separate cutting tool (24). A rough truing cut is made with a first cutting tool (24) and a final finish cut is made with a sharp second cutting tool (24) having cutting surfaces unused except on the finish surfaces.

Abstract: A tool set for gauging and repairing concentricity of a workpiece bore axial section with the pitch diameter of the internal threads in the bore includes a gauge sleeve, a gauge rod, a reamer, and a stop collar. For gauging concentricity of the internal threads with the axial section, the sleeve is first inserted within the bore and threaded into a concentric relationship with the bore internal threads, and, then, the rod is inserted through the sleeve. The rod has an inner end which can extend from the sleeve and within the bore axial section such that the rod inner end will extend through a predetermined distance if the axial section of the bore is concentric with the sleeve and thus with the pitch diameter of the internal threads within the bore.

Abstract: A fluid supply pipe (1) is drilled and tapped using a saddle (2) adhered to its surface, the drilling and tapping tools being attached to the saddle. The saddle (2) comprises a sole plate (3) snugly fitting on the pipe, and an upstanding collar (4) with a through bore (20) through which the cutting and tapping tools pass. During adhering the saddle to the pipe, adhesive is prevented from entering the bore (20) by provision of a closure member (21).

Abstract: A method for using a die holder with centering and squaring guide to cut preliminary and final threads on rotatable stationary workpieces is provided and includes a locating pin, a die with set screw, a shim, a die holder with two lock screws, a guide, three bolts, a guide bushing and a gage. The guide bushing presents alot more surface area to guide the workpiece into the die and which holds the workpiece absolutely square to the die throughout operation of making a machine quality thread on the workpiece.

Abstract: A method of threading or rethreading a member by the use of a die made up of a plurality of complementary separable interfitting parts held together by a tensional element disposed around the exterior surface thereof which in use are separated from one another under the tension of an abrasing element thereby enabling the die to be passed over the member whereat the separating force is relaxed permitting the parts to re-engage thereon. The die is then turned to effect the cutting of the threads.

Abstract: A device is disclosed for driving conventional hole saws and for extruding sawed material from within said saws after sawing. An internally right hand threaded shank is attached to the outer base end of a conventional hole saw. A cooperating mandrel is threaded into the shank from within the hole saw. The end of the mandrel remaining in the hole saw forms wing-like projections which spiral into the hole saw as the mandrel is threaded into the shank. A sleeve freely mounted on the shank contains pins which protrude into the saw through complimentary holes provided in the base of the conventional hole saw to obstruct the spiral motion of the mandrel projections to transfer torque from the mandrel to the saw for sawing, and the sleeve is moved away from the hole saw on the shank, withdrawing the pins from within the saw to free the mandrel to thread out through the saw to extrude sawed contents therefrom.

Abstract: A highly accurate positioning system used in connection with a photoplotter assembly employing a dual axis drive system having low mass and low inertia components. The drive elements of the system are low cost, high tensile strength drive bands that orient the driven members with high accuracy, low noise and require no lubrication. A photoplotter head and a moveable work table are similarly mounted to a base structure in a slideable manner utilizing a recirculating ball guide assembly and a flat rail roller assembly. The drive bands are moved by friction drive motors and a closed loop feedback control system orienting the photoplotter head and the work table relative to each other and utilize input only from the actual placement of the photoplotter head and the work table in calculating further movements. The work table is a lightweight element formed from a honeycomb infrastructure that provides individual vacuum chambers to hold a workpiece down on the work surface without external holding means.

Abstract: A device for adjustably controlling the position and set-back of a piston rod which extends from a damping cylinder used on an airfeed peck drill. The device includes a plurality of ball members which surround the piston rod. The ball members are positioned against the piston rod by a spring biased cone having a tapered internal surface. The balls are further positioned with respect to the cone by a spring biased ball separator which is movable with respect to the cone by air pressure. The travel of the piston rod is made adjustable by a nut member threadably engaged with the housing.

Abstract: Disclosed is an improved back-up sheet for backing a workpiece during a small bore drilling process. The sheet also possesses electrical properties making it an ideal candidate as a laminate (reinforcing layer or bonding sheet) in the construction of multi-layer printed wiring boards. The sheet or laminate comprises the cured residue of:(a) polyphenylene oxide;(b) a bisphenol A-type epoxy resin; and(c) an amine hardener for said epxoy resin, the weight ratio of a:b+c ranging from about 1:10 to 1:2.

Abstract: A portable system for reworking the inside diameter of heavy oil field casing, and especially casing that has irregularities on the inner surface thereof that render the casing unsuitable for use in deep wells. A cutting head assembly is rotated as it is forced into the interior of a joint of casing. The cutting head assembly includes a mandrel which turns a special cutting device having a plurality of cutters of engaging and cutting the inner wall of the pipe as the entire cutterhead is forced to travel through the pipe. Alignment members attached to the mandrel on either side of the cutting device maintain the longitudinal axis of the cutters in proper alignment to produce the desired new pipe inside diameter. After the first half of the pipe is sized or trued, the joint of casing is reversed and the other half is cut to the same new desired inside diameter.

Abstract: There is disclosed a method for machining multiple holes in a workpiece to a uniform depth and at a predetermined angle to the surface of the workpiece. The method is performed by a numerically controlled machine tool which orients the workpiece in space with respect to a reference coordinate system which establishes an expected position of the surface of the workpiece. The actual position of the surface of the workpiece is determined by sensing contact between the workpiece and the boring tool. Once the actual position of the workpiece surface has been sensed, the tool is advanced a predetermined distance to provide a uniform depth cut. The expected position, the actual position, and the deviation between the two are recorded to assure that the surface of the workpiece is accurately sensed during subsequent machining steps.

Abstract: A metal work sheet is prepared for routing operations by securing it to a backing panel with a releasable contact adhesive. The coated panel is initially covered by a release sheet, which is removed prior to the placement of the metal work sheet. Areas isolated by the routing can be pulled free of the adhesive, and the remaining work sheet can also be removed without adhesive contamination of the metal parts.

Abstract: A drilling and thread-milling tool is disclosed which has at its front-end 7 at least one end-cutting edge 8 for making a core-diameter hole and, behind it, non-pitched thread-milling teeth 4 to generate thread pitches and for which are provided an axial motion, rotation about its own axis as well as a helical motion. It is desirable that one tool should be adapted for making core-diameter holes of different diameters essentially by means of the end-cutting edge. This is accomplished in as much as the outer diameter of the end-cutting edge 8 is equal to or smaller than the minor diameter of the thread-milling teeth 4, in that the number of thread-milling teeth 4 arranged in axial succession is less than the number of thread pitches to be produced, in that provision is made for the simultaneous cutting of the core-diameter hole and thread pitches and in that the helical motion serving to generate the thread pitches consists of a number of orbits corresponding to the number of thread pitches to be generated.

Abstract: A portable line boring machine has a rotatable boring bar on which a tool bit is mountable. A first drive mechanism rotatably drives one end of the boring bar. A second drive mechanism linearly drives the first drive means and the boring bar along the longitudinal axis of the boring bar. A frame supports the first drive means, the second drive means and the boring bar.

Abstract: Thru-holes are drilled in a printed circuit board panel having alternating dielectric layers and electrically conductive layers. A water soluble dry film lubricant sheet is placed adjacent an electrically conductive outer layer of the panel prior to drilling thru-holes through the panel with a rotary drill. The drill surface is lubricated while forming a clean thru-hole from contact between the drill and the lubricant. The dry film lubricant generally may comprise a water soluble lubricant hardened to a solid or semi-solid dry film-form and impregnated in a carrier such as a porous paper sheet. In one embodiment, the dry film lubricant includes a water soluble lubricant such as dipropylene glycol, a non-ionic surfactant, and a wax-like hardener. Following drilling of the thru-holes, the dry film lubricant sheet is removed, and the thru-holes can be rinsed in an aqueous alkaline solution.

Abstract: The wear life of a high-speed tool steel cutting bit is increased by (a) cleansing the bit by subjection to an ion beam; (b) while preventing the temperature of said cleansed from rising above 350.degree. C., coating the cleansed bit by condensing sputtered atoms of titanium and boron thereonto, the condensation being carried out to provide a coating thickness of 2-6 microns. An argon or krypton beam of ions is accelerated to 1300-1800 volts as a broad-beam ion source to sputter a titanium diboride target arranged as a cathode. The sputtering is carried out for 5-10 minutes while the bit is heated to about 200.degree. C., and a soft vacuum of about 4-6 milli-torr is used during the process.

Abstract: A lightweight machine for drilling a pattern of fastening holes in panels of installed roofing insulation is movably supported on rollers that rest on the panels without substantially deforming them. The machine is maneuvered by a handle, and vertical movement of the handle lowers a template carrying a gang of drills. The drills proceed through a central opening in the frame of the machine to engage the panels in the sub-roof structure on which they have been installed.

Abstract: A method and apparatus for dispensing a smear-preventing solution onto a drill bit used for drilling printed circuit boards includes a drilling jig having a drill bit for engaging the printed circuit board and a dispensing system for dispensing a smear-preventing solution under pressure so that it sprays onto the drill bit through a hole in a pressure foot as the drill bit engages the printed circuit board. A switch mounted on the drilling jig controls the dispensing of the solution so that the solution is dispensed during the time that the drill bit is in the vicinity of the printed circuit board, and is turned off when the drill bit leaves the printed circuit board, or when the drill is turned off. A vacuum hose connected to the housing creates a low pressure condition adjacent the drill bit which provides for coating the drill bit while the solution is being dispensed, and for pulling the excess solution and debris created by the drill bit away from the surface of the printed circuit board.

Abstract: An apparatus for boring a laminated plate includes a table having a first surface on which a laminated plate may be placed for boring and an opposing second surface, the table defining at least one passage therethrough; a supporting pad for urging a laminated plate to be bored towards the first surface of the table; and a cutter for boring a laminated plate to be bored, the cutter operable to bore in a direction generally opposite to the direction that the supporting pad urges and through the passage defined by the table. Further according to the present invention, the cutter includes a knife edge, a pivotal mechanism adapted to be pivoted about its axial center line, and a stepping mechanism for moving the knife edge in one direction and unsuccessively further in a second direction so that successively deeper boring may be performed.

Abstract: A method and apparatus for determining the angular position of a workpiece and for positioning the same relative to at least one tool. The workpiece has at least one set of teeth. Pulses are derived from a rotating reference workpiece and from a reference shaft which has a known gear ratio with the reference workpiece, and consequently also turns. A first phase measurement is undertaken between the pulses, the result of which is stored as the reference value. The reference workpiece is replaced with a workpiece which is to be machined and which is provided with teeth. A second phase measurement between the pulses of the refernece shaft and of the reference workpiece are undertaken in a second measuring operation. The reference value of the first phase meaasurement is compared with the result of the second phase measurement. The workpiece is turned relative to the reference shaft in conformity with the difference between the two measured values.

Abstract: A method and apparatus for use with a panel having at least first and second targets thereon detectable with x-rays and comprising relatively moving the panel and an x-ray detection apparatus along a search path to locate the targets on the panel. With the targets located work operations, such as drilling and shearing, are performed on the panel.

Abstract: A tapped hole produced in a metallic material by threading a preselected standard threaded fastener into an untapped hole formed in the material. The diameter of the hole to be formed is determined by using a formula that takes into account the hardness and thickness of the material to be tapped and the basic major diameter and pitch of the preselected threaded fastener to be used to tap the hole. This formula can only be used with threaded fasteners having threads of the Unified Thread Standard type. This formula is particularly useful in tapping a hole formed in a mounting strap of an electrical wiring device.

Abstract: A pair of openings (14) are drilled in a workpiece (12) at locations spaced inwardly from an edge (76) of the workpiece (12). Each opening is cold-expanded by the passage of a mandrel (46') only, or a mandrel (46) and split sleeve (58), to create an annular zone of residual compressive stresses (72) in the workpiece material immediately surrounding the openings (14'). Then the workpiece (12) is cut along lines extending from the edge (76) inwardly to central regions of the cold-expanded openings (14'). The workpiece material between the two openings (14') and the two cuts (74) is removed. The edge portions (72) of the material in the vicinity of the cuts (74) and the openings (14') are machined to a final desired size and shape, to define connector slots (84) having cold-expanded round regions bounding the slots (84).

Abstract: In a method of drilling a printed circuit board according to the present invention, an entry feed rate at which a drill is fed into the printed circuit boards during the initial stage of drilling is made slightly smaller than a drilling feed rate at which the drill is fed while it is drilling a hole through the printed circuit boards, so as to enhance the accuracy at which holes are located. One drilling operation includes a plurality of drilling feeds of the drill, and pulled-out positions of the drill which are reached by the drill between adjacent drilling feed rate are set within a range in which the pressure of a pressure foot is effective. This can prevent the stacked printed circuit boards from shifting and increase the accuracy at which the holes are located.

Abstract: A methode serves for producing bores in wheels of motor vehichles, in particular for producing mounting bores (14) in a wheel disk (12) or valve bores in a rim of the wheels. The bore has a larger diameter (D.sub.1, D.sub.3) in the area of the surfaces (135, 136) of the wheel disk than in the area between these surfaces.In order to enable a countersunk portion to be produced in the area of the bore also in the surface opposite the machining surface, with the wheel in a signle mounting position, a tool (160) is employed whose bottom face exhibits a hook-like configuration (162, 163, 164, 165) and which can be passed through the bore in vertical direction (170), in axially displaced relation. Thereafter, the tool (160) is returned to a position in which it is aligned with the axis (15) of the bore, then rotated and retracted. whereby a countersunk portion (144) of larger diameter is produced. Finally, the tool can be removed from the bore by carrying out the described steps in the reverse order.

Abstract: An apparatus and method are provided for precisely positioning a locksmith tool in the area of a dial ring of a combination lock of a safe. The apparatus includes a derrick that holds and supports the locksmith tool. An offset, annular base forms a part of the derrick and has an opening with an inner diameter substantailly corresponding to the diameter of the outer periphery of the dial ring. The base is placed over the dial ring and radially extending set screws in the base are tightened into engagement with the dial ring. In this manner, the derrick is securely attached to the safe. The apparatus also includes a mechanism for precisely controlling and adjustably positioning the tool relative to the safe.

Abstract: An apparatus for receiving a tool carrier comprises a tool holder defining a receiving bore adapted to receive a portion of the tool carrier, an arrangement for supplying pressurized fluid to the receiving bore of the tool holder to clean adjacent surfaces of the tool holder and the tool carrier during insertion of the tool carrier into the receiving bore; and an arrangement for detecting the pressure of the fluid supplied to the tool holder for ascertaining whether correct operational positioning of the tool carrier exists with respect to the tool holder.

Abstract: Methods are disclosed of making and of using a high density high strength titanium diboride comprising material. The method of making comprises (a) compacting a mixture of titanium diboride, 5-20% by weight of a metal group binder, and up to 1% oxygen and up to 2% graphite, the mixture having a maximum particle size of 5 microns, and (b) sintering the compact to substantially full density. The TiB.sub.2 may be replaced by up to 10% TiC. The method of use is as a cutting tool at relatively high speeds against aluminum based materials.

Abstract: A method of providing interchangeability of aircraft wings, particularly providing a method of adjusting the angles of incidence and dihedral to compensate for differences in the twist angle between airfoils. The method comprises determining the angle of twist of an airfoil, having an airfoil attachment member, and supporting the airfoil on at least three supports spaced about said airfoil so that the airfoil attachment member is aligned with a hole boring means. The supports are adjusted so that the hole when bored through the airfoil attachment member provides the airfoil with angles of incidence and dihedral that substantially cancel the angle of twist. The hole is bored through the airfoil attachment member.

Abstract: The trust exerted on a drill bit is sensed and employed to determine the speed at which the bit is driven. A controller for the drill compares the thrust to a predetermined threshold value and in response to the comparison emits a control signal which shifts a transmission in the drill into high or low speed. After each shift, a number of thrust samples are taken in order to compute an average thrust for different strata of the material being drilled. At the completion of drilling each hole, the average thrusts for the hole are used to recalibrate the shift threshold value. In this manner, the shift threshold is adjusted to compensate for drill bit wear. The sensed thrust is also compared to a bit reject threshold value to determine when the bit is too dull for proper drilling.

Abstract: Stitch-machining the walls of a cylindrical blind cavity of a workpiece, the cavity being deep and narrow with respect to the axis of the cavity, is carried out by: (a) supporting a tubular housing for axial movement throughout substantially the axial extent of the cavity interior and in close-fitting tolerance to the walls of the cavity, the tubular housing having a free end; (b) rotationally driving a spindle (10,000-40,000 rpm) in the tubular housing for conjoint axial movement with the tubular housing, the spindle extending beyond the housing end for carrying a radially adjustable cutting tool; (c) inserting the tubular housing together with the rotationally driven spindle into the cavity (at lineal speeds of 400-800 inches/minute) with a cutting tool radially positioned for rough boring of the cavity walls, while guiding and steering the tubular housing and spindle to accurately concentrically position the cutting tool with respect to the cavity axis; (d) substantially immediately upon the execution of r

Abstract: Method and apparatus for conducting boring of a series of spaced walls on a workpiece using a self-adjusting boring bar.

Abstract: Valve seats are machined at the end of an axially deep, narrow cavity of a workpiece having an axially clampable surface within the cavity adjacent one or more valve seats. The method comprehends: (a) supporting a rotary driven spindle assembly of sufficient length to extend through the axial extent of the cavity and reach the valve seat, the spindle carrying a cutting tool at its extremity, the support being in a nonrotatable housing effective to fit closely to the interior of the cavity (within a tolerance of 0.

Abstract: Subterranean service pipes, eg. water mains, are tapped by minimal excavation to expose the upper half of the main and then locating (with respect to the main) a conventional pipe-tapping device but without employing means encircling the pipe. Thus, a clamp can be used, or a saddle adhesively secured to the pipe. The clamp or saddle preferably provide means for proper orientation of the drilling and tapping tool with respect to the main.

Abstract: A cutting tool assembly including an elongated pilot holder and a cutter blade adapted to be transversely positioned in a transverse slot in the pilot holder. The cutter blade includes cutting edges along one transverse edge of the blade and notches in the upper and lower transverse edges of the blade for respective coaction with a set scrw received in a threaded central axial bore in the lower pilot end of the pilot holder. In use, the lower pilot portion of the pilot holder is positioned in a previously provided pilot hole in a plate member, and the pilot holder is lowered and simultaneously rotated to move the cutting edge of the cutter blade into the upper face of the plate member to perform a cutting operation in the upper face, whereafter the pilot holder and cutter blade are raised, the set screw is loosened to allow removal of the cutter blade from the pilot holder, the pilot holder is lowered to dispose the slot below the lower face of the plate member, the cutter blade is rotated through 180.degree.