NIMS Core Manual Turning Skills 262
NIMS Core Manual Turning Skills 262 covers skills necessary for the Turning Operations: Turning Between Centers and Turning Operations: Turning Chucking Skills competencies within the NIMS Level 1 Machining standard. This course covers engine lathe components, setup, and cutting operations.
Taking this course in conjunction with the other listed requirements for the NIMS Level 1 Machining standard will prepare users for certification in Turning Operations: Turning Between Centers and Turning Operations: Turning Chucking Skills.
Number of Lessons 25
- Machining Order of Operations
- Manufacturer’s Technical Data References
- Introduction to Lathe Setup
- Lathe Components
- Cartesian Coordinates
- Spindle Noses
- Aligning the Workpiece
- Cutting Tool and Spindle Alignment
- Zeroing the Cutting Tool
- Adjusting the Cross Slide and Carriage
- Lathe Operations
- Lathe Operation Basics
- Turning Principles
- Turning Operations
- Facing Principles
- Facing Operations
- Taper Turning Methods
- External Taper Turning Using a Taper Attachment
- External Taper Turning Using the Compound Rest
- Taper Turning Using the Tailstock Offset
- Threading Operations
- Knurling Operations
- Parting Off and Grooving Operations
- Describe the order of operations normally performed when machining a part.
- Describe finishing processes.
- Describe how machinists use technical data references.
- Describe engine lathe setup.
- Describe basic components of the engine lathe.
- Describe how the Cartesian coordinate system relates to the engine lathe.
- Describe common workholding devices for the engine lathe.
- Describe common spindle noses for the engine lathe.
- Describe alignment of the workpiece to the spindle on the engine lathe.
- Describe how to properly align the cutting tool with the spindle on the engine lathe.
- Describe how to zero the cutting tool on the X and Z axes.
- Describe how to adjust the cross slide and carriage on the engine lathe.
- Describe common operations performed on the engine lathe.
- Describe common principles for turning.
- Explain how to perform a turning operation.
- Describe facing principles.
- Describe facing operations.
- Describe common taper turning methods used on the lathe.
- Describe how to turn an external taper using a taper attachment.
- Describe how to turn an external taper using the compound rest.
- Describe taper turning using the tailstock offset.
- Describe threading operations.
- Describe knurling operations.
- Describe parting off operations. Describe grooving operations.
The accurate positioning of parts in a mechanical system in relation to one another. Alignment on a lathe requires the workpiece and spindle to share a common centerline.
The process of joining objects. Assembly can include the use of fasteners, adhesives, or welding.
An imaginary straight line that is used to measure the location of an object in three-dimensional space. The Cartesian axes on an engine lathe are the X axis, Z axis, and C axis.
A type of alignment describing the workpiece when one end is concentric and the other is not. A part with axial runout is eccentric.
Raw material purchased from metal manufacturers in the form of long bars. Bar stock may be round, square, or hexagonal.
The base of the lathe. Beds provide a foundation for various machine tools.
bill of materials
BOM. A report that lists the materials required to make a particular product and the cost of each individual component. A bill of materials includes all project materials, including any accessories and fasteners.
bonded abrasive wheel
A grinding tool made of grits that are held together with chemical bonding and formed into a circular shape. A bonded abrasive wheel rotates along the surface of a part to remove material.
The process of enlarging an existing hole with a single-point tool. Boring is an inner diameter operation.
A cylindrical toolholder used to position a single-point tool for internal cutting operations. A boring bar is used for internal taper turning operations on the lathe.
A rough, sharp edge remaining on a part after a cutting process. Burrs pose an injury risk and interfere with the fitting of parts.
The Cartesian axis describing motion around the Z axis. The C axis describes the rotation of the spindle on a lathe.
A type of fastener used to secure a chuck to a cam-lock spindle nose. A cam lock contains a base that a chuck key can attach to and turn the cam, which latches the cam-lock in place.
cam-lock spindle nose
A type of spindle nose in which the workholding device is held in place with cam-locks around its perimeter. Cam-lock spindle noses are often used on high-powered machines.
The combination of components that make up the carriage. The carriage assembly includes the saddle, cross slide, compound rest, tool post, and cutting tool.
A hand-cranked wheel that moves the lathe carriage back and forth along the ways, parallel to the workpiece. The carriage handwheel positions the cutting tool for turning operations.
Cartesian coordinate system
A system that describes the location of an object by numerically expressing its distance from a fixed position along three linear axes. Cartesian coordinates are used to direct machine tool movements.
A pointed device that mounts in the headstock and tailstock and supports a workpiece at one or both ends. Centers are inserted into holes drilled into the ends of a workpiece.
Cutting a wide center hole into the end of a workpiece using a special center drill bit. Center drilling can create a hole that can be used by a center to support the workpiece or can act as a pilot hole for drilling operations.
An instrument that checks the angle of a cutting tool to a workpiece. Center gages help ensure the cutting tool is perpendicular to the workpiece for threading operations on a lathe.
Using a center drill to make a tapered hole in the end of a part. Once a part is center-drilled, the center can support it using the tapered hole.
An imaginary line that divides a shape into two equal halves or that runs through the center of a cylindrical object. A cylindrical workpiece rotates along a centerline.
A form of threading. Chasing occurs to repair damaged threads.
The proper removal of chips during a metal-cutting process. Chip evacuation can become an issue if the operation generates a lot of vibration, as with grooving, or when machining without enough cutting fluid, which can result in a damaged cutting tool or scrapped part.
An unwanted piece of material that is removed from a workpiece. Chips are formed when a tool cuts or grinds a workpiece.
A device that holds a workpiece in place as it rotates on a lathe or other machine. The chuck commonly has two, three, or four jaws that can be adjusted to fit various workpieces.
A device used to loosen the bolts or cam-locks on a chuck. A chuck cannot be removed from a cam-lock spindle nose without the use of a chuck key.
A finish used for protective and decorative purposes. Coatings like paint or varnish are applied to products at the end of the part creation process.
A slotted device that holds a workpiece or cutting tool in place as it rotates. A collet has a hole through which the workpiece or tool passes and is designed to hold specific dimensions.
The part of the lathe that holds the tool post. The compound rest makes smaller movements than the cross slide for making finer cuts.
compound rest feed dial
The lined scale on the compound rest handwheel that indicates the measurement of the feed. The compound rest feed dial sets the depth of cut.
compound rest handwheel
A hand-cranked wheel that moves the compound rest back and forth. The compound rest handwheel feeds the cutting tool for turning operations.
Inwardly curved in shape. Concave surfaces can form during parting off operations if there is improper cutting tool alignment.
Having a common center or sharing the same axis with another object. When the workpiece and lathe spindle share a common centerline, they are concentric.
A cylindrical feature that gradually changes from a larger diameter to a smaller diameter at a constant ratio. Conical tapers are machined on the lathe using a taper attachment or by positioning the tailstock off-center.
Outwardly curved in shape. Convex surfaces can form during parting off operations if there is improper cutting tool alignment.
The part of the carriage assembly on a lathe that holds the compound rest. The cross slide moves the cutting tool perpendicular to the workpiece.
cross-slide feed lever
A lever located on the carriage assembly that controls movement of the cross slide. The cross-slide feed lever can be set to automatically feed the carriage toward or away from the chuck.
A hand-cranked wheel that moves the cross slide on a lathe back and forth, perpendicular to the workpiece. The cross-slide handwheel brings the cutting tool into and out of contact with the workpiece.
A cutting operation performed on a lathe that uses a cutting tool to separate a finished part from the rest of the stock. Also known as parting off, cutoff is an outer diameter operation.
A cutting tool designed to separate a finished workpiece from the bar stock. A cutoff tool is usually a thin blade of high-speed steel.
A substance used to cool and lubricate a metal-cutting process. Cutting fluids are typically oil- or water-based liquids.
A device made of hard, tough material that is used to remove metal by creating chips. Cutting tools used for lathe operations are usually single-point tools such as carbide inserts.
A center that remains stationary during a turning operation. A dead center does not turn with the workpiece.
depth of cut
The distance that a cutting tool penetrates the surface of a workpiece. Depth of cut is set on the compound rest feed dial for taper turning operations on the lathe.
A measuring instrument used to indicate linear movement. Using a dial indicator is the best way to make sure a workpiece is properly aligned with the spindle.
The distance from one edge of the circle to the opposite end through the center. The diameter is always twice the size of the radius.
DRO. A type of readout that uses an encoder attached to a machine that transfers information to a digital display. Digital readout is capable of very precise measurements.
A measurement of space, especially length, width, and height. Dimensions of a part are detailed in a blueprint.
The screen that displays information about a machine for the operator. Display panels indicate the position of the workpiece on a manual milling machine.
The use of a multipoint tool to machine a new round hole into the surface of a workpiece. Drilling is an inner diameter operation.
A manual cutting fluid delivery method in which an operator uses a brush to apply fluid on the workpiece surface. The drip method is often used with oil-based cutting fluids.
Digital readout. A type of readout that uses an encoder attached to a machine that transfers information to a digital display. DRO is capable of very precise measurements.
Not having a common center. Eccentric rotating components do not share the same centerline, or axis.
The original and most basic type of manual lathe. An engine lathe holds a cylindrical workpiece on one or both ends.
A turning operation performed on a lathe that feeds a cutting tool across the end of a cylindrical workpiece to create a flat surface. Facing is an outer diameter operation.
An operation performed on a lathe that feeds a cutting tool across an end of a cylindrical workpiece to create a flat surface. Facing is an outer diameter operation.
A device that holds objects together or locates them in relation to one another. Common fasteners include screws, bolts, and rivets.
The rate at which the cutting tool and the workpiece move in relation to one another. Feed is typically a linear movement.
A device of known thickness used to measure small distances. Feeler gages come in a range of sizes.
A cutting pass that emphasizes tight tolerances and smooth surface finish. Finishing is usually the last step in the machining process.
The amount that a part bends due to pressure from the cutting tool. A smaller diameter part will flex less often if the tool is fed away from the chuck.
The amount that a part bends due to pressure from the cutting tool. Flexing is less drastic on smaller diameter parts if the tool is fed away from the chuck.
A cutting tool ground to a specific shape that is used to create that shape in a workpiece surface. Form tools used for grooving on the lathe are often square or V-shaped.
A cutting tool ground to a specific shape that is used to create that shape in a workpiece surface. Form tools used for grooving on the lathe are often square or V-shaped.
An analog device that measures linear movement. Graduated dials are numbered collars attached to handwheels on the lathe that record and measure movement and positioning.
A machine that uses an abrasive to remove material from the surface of a workpiece. Grinders include surface grinders, centerless grinders, and cylindrical grinders.
The use of an abrasive tool to remove material from a workpiece. Grinding operations commonly use abrasive grains bonded into a wheel shape.
A machining operation performed on the lathe that cuts a narrow channel into the surface of a rotating cylindrical workpiece. Grooving can be an inner or outer diameter operation.
An adjustable steel rod on a taper attachment. The guide bar sets the taper angle for taper turning.
A sliding component on a taper attachment. The guide shoe slides on the guide bar and directs the cross slide feed at an angle to create a taper.
The component of the lathe that holds the motor, gearbox, and spindle. The headstock powers the lathe.
Controlled heating and cooling processes used to change a material's structure and alter its physical and mechanical properties. Heat treatment often adjusts a material's hardness.
A type of measuring instrument with a precision finished base, a perpendicular beam, and an indicator. A height gage can be used in conjunction with a planer gage to align a cutting tool to a lathe spindle.
Six-sided. Hexagonal workpieces can be held by self-centering and independent chucks.
Internal diameter. The inner surface of a hole or cylindrical feature. ID operations on the lathe include drilling, reaming, and boring.
A type of chuck with jaws that can each move separately. Independent chucks can grip irregularly shaped workpieces during lathe operations.
ID. The inner surface of a hole or cylindrical feature. Internal diameter operations on the lathe include drilling, reaming, and boring.
A surface that can be used to take accurate measurements. A surface becomes known after it is machined to a definite measurement.
A forming process that adds a pattern on the exterior surface of a workpiece, slightly increasing the workpiece diameter by displacing material. Knurling produces a textured, rough pattern embedded into the part's surface, either for cosmetic reasons or better handling.
A machining operation that displaces material rather than cutting it. Knurling embeds a textured, rough pattern into a part's surface.
A machine tool used to create cylindrical parts. A lathe holds a cylindrical workpiece on one or both ends while a cutting tool is gradually passed along or into the surface of the rotating part.
A workholding device that clamps onto the workpiece and transmits rotary motion from the spindle of a lathe to the workpiece. The lathe dog allows a workpiece to be mounted between centers.
A fluid that is brushed on a metal workpiece before operation. Layout dye allows the lines and features to be seen more clearly.
A type of center that uses bearings or friction so that the center rotates with the workpiece in the headstock. Live centers are also called driving-type centers.
The process of removing material to form an object. Machining methods include milling, turning, and drilling.
manufacturer’s technical data references
Documents provided by a manufacturer that provide specific information about the products they manufacture. Machinists use manufacturer’s technical data references to help them select the proper cutting tool for a given operation.
A machining process that uses a tool to remove metal from a workpiece in the form of chips. Metal cutting operations include milling, drilling, and turning.
A U-shaped measuring instrument with a threaded spindle that slowly advances toward a small anvil. A micrometer must be used to accurately measure the true diameter during and after a turning operation.
A mechanical device attached to the ways of a lathe and mounted in front of or behind the carriage. The micrometer stop limits the travel of the carriage assembly when in automatic mode.
A small protrusion or burr on a workpiece surface. Nibs form when a machinist aligns the cutting tool below the spindle centerline when setting up an engine lathe for operation.
Outside diameter. The outer surface of a cylindrical workpiece or feature. OD operations on the lathe include turning and parting off.
Any location on a part that deviates from the part's centerline. Off-center turning requires an independent chuck rather than a self-centering chuck.
A turning operation on a lathe in which the workpiece centerline axis is not continuously aligned with the Z axis. Offset turning operations include taper turning.
An employee who runs a machine. Operators are trained to safely set up, run, and maintain their particular machine.
The fixed central point in the Cartesian coordinate system. The origin has a numerical value of zero at each axis.
OD. The outer surface of a cylindrical workpiece or feature. Outside diameter operations on the lathe include turning and parting off.
Two lines or axes that are equidistant at all points along their length. Parallel lines, axes, or components never touch or intersect.
Two surfaces of a workpiece with all opposing points equidistant from each other. Parallel surfaces are often a requirement on cylindrical workpieces machined on an engine lathe.
A cutting operation performed on a lathe that uses a cutting tool to separate a finished part from the rest of the stock. Parting off, also known as cutting off, is an outer diameter operation.
The outer edge or rim of an object or tool. Both the periphery and face of the cutting tool are used in milling.
Meeting at a 90° angle. The cross slide movement is perpendicular to the spindle axis.
The distance between a point on an individual thread to the corresponding point on the next thread. Pitches range from coarse, with few threads, to fine, with many threads.
A work aid consisting of two right-triangle metal blocks fastened together. A planer gage allows users to measure dimensions of parallel surfaces within a range by sliding one block onto another.
A document containing all the instructions necessary to manufacture a part. A print includes a part drawing, dimensions, and notes.
A lathe component that houses the gears that control the power transferred from the motor to the spindle. The quick-change gearbox allows the spindle speed and rotation to be adjusted quickly.
A set of toolholders that uses a master toolholder with a series of rapid, interchangeable toolholders. Quick-change tooling increases the speed of production, but operators must check alignment after changing tools.
A type of alignment describing whether or not the workpiece is concentric to the centerline of the lathe spindle. If a workpiece runs true, it has a proper radial alignment.
The process of enlarging or smoothing an existing hole with a multipoint tool. Reaming is an inner diameter operation.
The quick removal of metal from a workpiece without regard to tolerances or finish. Rough cuts are made with high feed rates and large depths of cut.
A cutting pass that removes material without regard to surface finish. Roughing is often used to separate part pieces from a single sheet of material.
Having a common center or sharing the same axis with another object. If a workpiece runs true, it shares a centerline with the lathe spindle.
When two rotating objects do not share the same axis of rotation. Runout determines the accumulated position error and deviation of a workpiece exterior or interior from a center axis as the workpiece rotates.
The base of the lathe carriage assembly. The saddle rides along the ways to reposition the carriage assembly.
A form of grinding that uses a fine grain abrasive to remove small amounts of material. Sanding improves the finish of a surface.
A chuck with jaws that open and close together. Self-centering chucks accurately position a workpiece along the centerline of the chuck.
A type of screw with a rounded or cone-shaped end designed to fit into a matching recess. When loosened, set screws on the tailstock allow operators to offset the tailstock.
To establish a starting point on a workpiece or machine by setting the coordinate values to zero. To set zero, or zero the tool, an operator positions the tool in a location and then resets the analog measuring devices or DRO display to zero.
All the necessary preparation that occurs on a machine before an operation can be executed. Setup includes preparing machines, tools, and materials.
short taper spindle nose
A type of spindle nose in which the workholding device is held in place with fasteners around its perimeter. Short taper spindle noses are often used on high-powered machines.
A cutting tool that has one single cutting edge. Single-point cutting tools are usually made of high-speed steel or carbide.
The design parameters that set the limits of acceptable deviation for a part's intended application. Specifications are also called specs.
The rate at which the workpiece passes the cutting tool at the point of contact. Surface speed has the greatest effect on tool life.
A component of a lathe's headstock that rotates the workpiece. The spindle can be mounted with a workholding device to support the workpiece.
A component of the spindle onto which the workholding device is mounted. The type of spindle nose on the lathe determines the appropriate workholding device to use.
A device used to support long rotating workpieces. Steady rests can support longer workpieces for high-pressure operations on the lathe, such as knurling.
The degree of roughness and variation on the surface of a part after it has been manufactured. The surface finish of a part may need to be smooth or intentionally rough.
A common grinding process that uses a rotating grinding wheel to wear away precise amounts of a flat workpiece surface. Surface grinding is often one part of a sequence of machining operations.
A toolholder and mount opposite from the headstock. The tailstock can hold a center to support long workpieces or cutting tools, such as a drill bit.
Repositioning the lathe tailstock a small distance off the spindle centerline. A tailstock offset is one method for turning long tapers between centers.
tan. The ratio of the side opposite an angle of a right triangle to the side adjacent to that angle. Finding the tangent of an angle helps in finding the measurement of the angle in degrees.
A specialized lathe attachment that includes an angled guide bar and shoe used to machine a taper on a cylindrical part. A taper attachment is clamped to the lathe saddle and connects to the cross slide to guide its movement during taper turning.
taper per foot
TPF. The change in diameter for each foot along the length of a tapered cylindrical part. Taper per foot is calculated by dividing the difference between large and small diameters by the length of the taper, then multiplying the result by 12.
taper per inch
TPI. The change in the diameter for each inch along the length of a tapered cylindrical part. Taper per inch is calculated by dividing the difference between large and small diameters by the length of the taper.
A lathe cutting operation that gradually increases or decreases the diameter along the workpiece length to create a conical shape. Taper turning is an outer diameter operation.
The process of cutting internal threads in a round hole with a multipoint tool. Tapping is performed only after first drilling a hole.
A measuring instrument used to inspect the threads of a part. Thread gages are made for either internal or external thread inspection.
threaded spindle noses
A type of spindle nose that is screwed onto the spindle. Threaded spindle noses are often used on small lathes.
The process of cutting a long, helical groove into the exterior of a cylindrical workpiece with a single-point tool. Threading can also be an inner diameter operation, though outer diameter threading is more common.
A long, spiraling groove that may appear on the interior or exterior of an object. Threads help fasteners, such as screws, grip material and hold components together.
A space that has length, width, and depth. Three-dimensional space can be represented by the Cartesian coordinate system.
A blueprint specification indicating an unwanted but acceptable deviation from a given dimension. Tolerances state the allowable difference between a part and its intended design.
A lathe component that sits on the compound rest of the carriage assembly. The tool post contains a slot for positioning the toolholder and cutting tool.
To determine the exact location of a tool tip by touching it against an object with a known measurement. To touch off establishes a starting point for the cutting tool on the workpiece.
A machining operation that rotates a cylindrical workpiece while a single-point tool is guided along the length of a part. Turning is performed on a lathe.
A machining operation that rotates a cylindrical workpiece while a single-point tool is guided along the length of the part. Turning is performed on a lathe.
A thread set to a measurement standard based on inches. Unified threads conform to specifications of the American Society of Mechanical Engineers (ASME) and the American National Standards Institute (ANSI), both of which set standards in the United States.
A set of parallel tracks along which a machine component moves. The ways allow the carriage and tailstock to move along the bed of the lathe.
A method or device for securing a workpiece for a machining operation. Workholding can include chucks, vises, and clamps.
Any part that is being machined, formed, or otherwise worked on. Workpieces are turned on a lathe.
The Cartesian axis describing cutting tool motion toward and away from the spindle centerline. The X axis is perpendicular to the spindle centerline on a lathe.
The Cartesian axis that represents up and down movement, perpendicular to the X axis. The Y axis is not utilized on a manual lathe.
The Cartesian axis describing the location of the spindle centerline. The Z axis is always parallel to the spindle on a lathe.
zero the tool
To establish a starting point on a workpiece or machine by setting the coordinate values to zero. To zero the tool, or set zero, an operator positions the tool in a location and then resets the analog measuring devices or DRO display to zero.