uary 1999
Federal Wage System Job Grading Standard
For Machining, 3414


Table of Contents

WORK COVERED ........................................................................................................................................ 2

WORK NOT COVERED................................................................................................................................ 2

TITLES .......................................................................................................................................................... 3

GRADE LEVELS .......................................................................................................................................... 3

HELPER AND INTERMEDIATE JOBS ........................................................................................................ 3

NOTES TO USERS....................................................................................................................................... 4

MACHINE TOOL OPERATOR, GRADE 8 ................................................................................................... 5

MACHINE TOOL OPERATOR, GRADE 9 ................................................................................................... 7

MACHINIST, GRADE 10 .............................................................................................................................. 8

MACHINIST, GRADE 11 ............................................................................................................................ 10

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1 Machining, 3414

HRCD-6 January 1999
WORK COVERED

This standard covers nonsupervisory work involved in the manufacture of parts and items of
equipment from castings, forgings, and other raw stocks made of various metals, metal alloys,
and other materials, and/or machining operations required in the repair of such items. The work
requires the use of various types of conventional and/or computer numerical control (CNC)
machine tools and their attachments to perform machining operations in the repair and/or
manufacture of parts from raw stock.

The work performed by machine tool operators requires basic knowledge of machining
processes and skill in performing machining operations such as boring, drilling, planing, milling,
and turning on milling machines, radial, or multiple spindle drill presses, shapers, planers, lathes,
or equivalent types of conventional and/or CNC machine tools.

The work performed by machinists requires skill in the initial planning of necessary work
sequences, laying out reference points and lines to be followed in the machining processes,
planning for and setting up the work in the machine, sometimes programming the cutter path,
selecting and shaping metal cutting tools and inserts, operating all types of machine tools , and
performing precision handwork to fit, finish, and assemble machined parts and equipment. The
work also requires knowledge of the makeup of blueprints and drawings and the skill necessary
to interpret them; and skill in working from other types of specifications such as sketches,
models of parts to be manufactured, or work orders.

This standard cancels and supersedes the Job Grading Standards for Machine Tool Operator,
3431, issued in May 1973, and Machinist, 3414, issued in September 1973.

WORK NOT COVERED

- Planning and fabricating research and prototype models using machinist trade processes in
combination with those of one or more other trades (See
Job Grading Standard for Model
Making Series, 4714.
)

- Planning and fabricating research and prototype instruments using machinist trade processes
in combination with one or more other trades (See
Job Grading Standard for Instrument
Making Series, 3314.
)

- Fabricating, manufacturing, calibrating, reconditioning, and repairing tools, jigs, fixtures,
dies, punches, and gages used in the manufacture, overhaul, and repair of equipment
(See
Job Grading Standard for Toolmaking Series, 3416.
)

- Dismantling, repairing, relocating, modifying, maintaining, aligning, overhauling, and
installing a wide variety of machinery, equipment, and systems such as propulsion
machinery, lifeboat davits, anchor handling gear, and missile tube equipment that are located
U.S. Office of Personnel Management
2 Machining, 3414

HRCD-6 January 1999
aboard submarines, ships, and other floating craft. (See
Job Grading Standard for Marine
Machinery Mechanic Series, 5334.
)

- Dismantling, repairing, relocating, modifying, maintaining, aligning, overhauling, and
installing fixed and semi-fixed production machinery, equipment, and systems such as
various standard and numerically controlled machine tools, woodworking, and metalworking
machines used in the production of goods. (See
Job Grading Standard for Production
Machinery Mechanic Series, 5350.
)
- Dismantling, repairing, aligning, overhauling, and installing general nonproduction industrial
plant machinery, equipment, and systems such as bridge cranes, conveyor and pneumatic
tube systems, sandblasting machines, and other industrial waste and flood control equipment
such as compressors, pumps, and valves; and engraving machines, aircraft test block
equipment, and fire extinguishing systems. (See
Job Grading Standard for Industrial
Equipment Mechanic Series, 5352.
)

TITLES

Jobs at grade 10 and above that involve the manufacture and repair of parts and items of
equipment using a variety of conventional, nonconventional, and/or computer numerical control
machine tools are titled Machinist.

Jobs below grade 10 are titled Machine Tool Operator.

GRADE LEVELS
This standard does not describe all possible grades at which jobs might be classified. If jobs
differ substantially from the skill, knowledge, and responsibility levels or other work
requirements described in the standard, they may be graded either above or below the grade
levels described based on sound job grading methods.

HELPER AND INTERMEDIATE JOBS

Helper and Intermediate Machinist jobs are graded by the Office of Personnel Management
Job
Grading Standards for Trades Helper
and
Intermediate
Jobs. The grade 10 machinist in this
standard is to be used as the
A
full performance
@
level or grade in applying the Intermediate Job
Grading Table.

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HRCD-6 January 1999
NOTES TO USERS
PARTS PROGRAMMING


The evolution of parts programming from manually prepared programs using punch tape
equipment or a mainframe computer to the use of a mini, micro, and now personal computers
(PCS) has brought with it a revolution in how parts programs are generated.

With the power of the modern computer, the integration of CAD/CAM (computer aided design/
computer aided manufacturing) has become a reality. The various functions under CAD/CAM
fit roughly into three general areas: design/drafting, planning/scheduling, and fabrication. They
are sometimes referred to as computer-aided engineering, management information systems, and
manufacturing automation, respectively. CAD is often used separately as a term to cover all
those functions involved in readying a product idea for fabrication. CAM is applied to those
functions involved in producing that product, including the computer numerical control (CNC)
parts programming.

The heart of CAD is computer graphics-the computer systems that create, transform, and display
pictorial and symbolic data. In other words, computer graphics systems are high-speed
replacements for the traditional drafting boards, drawings, and documents used in
manufacturing. Any computer system that involves the display of a pictorial or graphic image is
considered a computer graphics system. The image can range from a simple, two-dimensional,
straightline plot of a cutter path to a multicolor representation of a three-dimensional assembly.
Such representations may feature sculptured surfaces and moving parts, with shading and
perspective to create the illusion of depth, which may be rotated and viewed like an object in
space.

PAY PLAN DETERMINATION


Parts programming complexity and difficulty rests on the geometry of the part being machined.
There are two levels of difficulty and complexity. The first level involves shop floor
programming. The second level involves developing computer programs for three-dimensional
contouring requiring simultaneous motion of 3 or more axis of machine tool motion. Level 1
involves up to three axis levels of programming complexity that is limited to drilling, boring, and
similar operations at a fixed XY coordinate axes location plus some straight-line milling in a
fixed plane and includes: repetitive and simple point-to-point; contour profiling limited to
straight lines tangent to circles and arcs; circles intersecting circles; straight lines intersecting
circles; pocket milling in a single plane with straight cuts; repetitive point-to-point operations
irregularly spaced about a circle; formula curves such as an ellipse; and pocket milling of
irregular pockets when points are described. Level 2 includes: pocket cleanouts at various
depths; drilling on an inclined plane and rapid traversing to a point above the plane; machining
an inclined plane; constant angular rotation of a cutter with tool axis normal to workpiece
surface; three axis simultaneous motion with cutter axis tilted-axis of cutter to remain parall