What is the definition of "drawbar"?
Usually, a threaded bar that fits through the spindle bore of a machine to hold and pull a collet or tapered toolholder tight against the spindle nose.

Learn more about drawbar in the class Taper Turning on the Engine Lathe 240 below.


Manual Machining Training


Class Information
Tooling U classes are offered at the beginner, intermediate, and advanced levels. The typical class consists of 12 to 25 lessons and will take approximately one hour to complete.
Class Name:Taper Turning on the Engine Lathe 240
Description:Taper Turning on the Engine Lathe 240 is an introductory class coverning methods for turning basic tapered parts on an engine lathe.
Prerequisites: 150115  150205  150225 
Difficulty:Beginner
Number of Lessons:10
Language:English, Spanish

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Below are all the competencies and job programs that contain the class Taper Turning on the Engine Lathe 240. Job programs are our traditional class lists organized according to common job functions. Competencies are our latest job-specific curricula that help tie online learning to practical, hands-on tasks.

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Competencies

Class Outline
  • Objectives
  • Overview of Taper Turning on the Lathe
  • Common Tapers
  • Common Methods for Turning Tapers
  • Calculating Taper per Foot
  • Taper Turning Using Tailstock Offset
  • Taper Turning Using The Compound Rest Method
  • Taper Measurement
  • Boring an Internal Taper
  • Summary
  
Class Objectives
  • Describe the purpose of a tapered machine tool component.
  • Describe common types of tapers.
  • Describe common methods for turning tapers.
  • Calculate taper per foot for a given example.
  • Describe how to turn a long taper using tailstock offset.
  • Describe how to turn a steep taper using the compound rest method.
  • Describe how to measure a taper.
  • Describe how to turn an internal taper.

Class Vocabulary

Vocabulary TermDefinition
American Standard A steep or long taper configuration that has been adopted by ANSI/ASME for use in machine tools. American Standard is used extensively in milling machines.
angle with the centerline The 1/2 angle of a taper, degrees measured from the centerline axis of a cylindrical part.
backlash The amount of slack, or play, between a leadscrew and nut that moves the cross-slide. Backlash grows over time and must be compensated for during turning.
Brown & Sharpe A standard taper with a taper per foot of 0.5000 inches (12.7 mm), except for B & S # 10, which has a tpf of 0.5161 inches (13.11 mm). Used mostly in milling machines and grinding machines.
compound rest A part of the cross-slide on a lathe that holds the toolpost, and can be rotated up to 90 degrees.
drawbar Usually, a threaded bar that fits through the spindle bore of a machine to hold and pull a collet or tapered toolholder tight against the spindle nose.
included angle The full angle of a taper, or twice the angle from the centerline of a taper.
Jarno A standard taper with a taper per foot of 0.6000 inches (15.24 mm). Used in some lathes, and many other machines.
long taper Any of a series of self-holding tapers, typically with long shanks and a taper angle of 2 to 3°, or less than one inch per foot.
micrometer A measuring device used for measurements of machined parts typically to within 0.001 of an inch, and sometimes to 0.0001 of an inch.
Morse taper A standard taper with a taper per foot of approximately 5/8 inch (approx. 15.875 mm). Used in a wide variety of machines, especially lathes, but exclusively in twist drill shanks.
ratio An expression of taper in inches per foot, such as 1:12.
self-holding Another term for a long taper, indicating that the taper is designed to be held in a spindle by friction.
sine bar A measuring device used specifically to precision measure angles. Taper micrometers include small sine bars, and can be used to measure taper angles without removing work from the lathe.
steep taper Any of a series of self-releasing tapers, typically with short shanks and a taper angle of 16° or 3.5 inches (88.9 mm) per foot.
tailstock offset A method of turning long tapers between centers in which the lathe tailstock is set a small distance off the centerline.
tangent In a triangle, the ratio of the side opposite an angle to the side adjacent to the angle. Finding the tangent of an angle helps a machinist convert to degrees in order to set up a turning operation properly.
taper The uniform change in diameter of a cylindrical workpiece when measured along its axis.
taper attachment A specialized lathe attachment that includes an angled guide bar and shoe used to machine a taper on a cylindrical part.
taper micrometer A specialized measuring device that includes a small sine bar mounted on an anvil that can measure taper angles without removing work from a lathe.
taper per foot The change in diameter of a cylindrical part measured in terms of inches per foot of length.
taper per inch The change in diameter of a cylindrical part measured in terms of inches per inch of length.
taper ring gage A measuring device with an internal taper used specifically to determine taper angle of a cylilndrical part.