Standard Test Method for Evaluating Machining Performance of Ferrous Metals Using an Automatic Screw/Bar Machine (Withdrawn 2023)

SIGNIFICANCE AND USE
5.1 This test method can be used to evaluate the machining performance of a single grade or type of metal or to compare one grade or type with another.  
5.1.1 The machining performance of the test metal is measured by the maximum rate at which test pieces can be produced within specified surface roughness and dimensional limits for a specified length of time and also by the cutting speed and tool feed employed to attain that rate.  
5.1.2 The relative machining performance of the various metals tested using this test method may be evaluated only at operating conditions that produce test pieces of like quality with respect to surface roughness and dimensional limits for comparable periods of machining time.
SCOPE
1.1 This test method covers a production-type test for evaluating the machining performance of ferrous metals as they are used in single-spindle or multiple-spindle automatic screw machines. It is based on producing parts of a standard design in such machines to uniform levels of quality with respect to surface roughness and size variation. The standard test piece, designed for this test, is machined from bars using a specified number of tools in a specified sequence. Nothing in this test method should be construed as defining or establishing limits of acceptability for any grade or type of metal.  
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
WITHDRAWN RATIONALE
This test method covered a production-type test for evaluating the machining performance of ferrous metals as they were used in single-spindle or multiple-spindle automatic screw machines. It was based on producing parts of a standard design in such machines to uniform levels of quality with respect to surface roughness and size variation.
Formerly under the jurisdiction of Committee A01 on Steel, Stainless Steel and Related Alloys, this test method was withdrawn in November 2023. This standard is being withdrawn without replacement due to its limited use by industry.

General Information

Status
Withdrawn
Publication Date
31-Aug-2018
Withdrawal Date
06-Nov-2023
Current Stage
Ref Project

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ASTM E618-07(2018) - Standard Test Method for Evaluating Machining Performance of Ferrous Metals Using an Automatic Screw/Bar Machine
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This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E618 − 07 (Reapproved 2018)
Standard Test Method for
Evaluating Machining Performance of Ferrous Metals Using
an Automatic Screw/Bar Machine
This standard is issued under the fixed designation E618; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
This test method was written to fill a requirement for a standard test for determining the
machinability of ferrous metals using automatic screw/bar machines. (Hereafter, these machines will
be referred to as automatic screw machines.) Although a variety of short-time laboratory tests have
demonstrated different machining characteristics among ferrous metals, it has been difficult to apply
the resulting data to commercial automatic screw machine practice.
In this test method a standard test piece is machined using tools and machining operations typical
of automatic screw machine practice.
Throughtheuseofthistestmethod,therelativemachiningperformanceofametalcanbeevaluated
even though different automatic screw machines are used. Further, comparisons can be made among
different lots of the same grade or different grades to determine relative machining performance.
1. Scope ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
1.1 This test method covers a production-type test for
mendations issued by the World Trade Organization Technical
evaluating the machining performance of ferrous metals as
Barriers to Trade (TBT) Committee.
they are used in single-spindle or multiple-spindle automatic
screw machines. It is based on producing parts of a standard
2. Referenced Documents
design in such machines to uniform levels of quality with
2.1 ANSI Standard:
respect to surface roughness and size variation. The standard
B46.1 Surface Texture
test piece, designed for this test, is machined from bars using
a specified number of tools in a specified sequence. Nothing in
3. Terminology
this test method should be construed as defining or establishing
3.1 Definitions of Terms Specific to This Standard:
limits of acceptability for any grade or type of metal.
3.1.1 average surface roughness (per set of samples)—for
1.2 The values stated in inch-pound units are to be regarded
each surface (the major and minor diameter formed surfaces)
as standard. The values given in parentheses are mathematical
the surface roughness per set of samples is the average of the
conversions to SI units that are provided for information only
roughnesses recorded as in 3.1.5.1 for the six test pieces per
and are not considered standard.
set. A test set is described in 9.3.
1.3 This standard does not purport to address all of the
3.1.2 calculated hourly production rate (in pieces per
safety concerns, if any, associated with its use. It is the
hour)—3600s/hdividedbythecycletimeinsecondsperpiece.
responsibility of the user of this standard to establish appro-
(Unit: pieces per hour.)
priate safety, health, and environmental practices and deter-
3.1.3 cycle time—the time in seconds per piece from bar
mine the applicability of regulatory limitations prior to use.
feed-out to bar feed-out, or from cutoff to cutoff, during
1.4 This international standard was developed in accor-
uninterrupted operation of the machine. It includes all stock,
dance with internationally recognized principles on standard-
machine, and tool movements.
3.1.4 surface speed—the product of the original bar circum-
1 ference (in feet or metres) and the spindle speed in revolutions
This test method is under the jurisdiction of ASTM Committee A01 on Steel,
Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee per minute. (Unit: ft/min or m/min.)
A01.15 on Bars.
Current edition approved Sept. 1, 2018. Published September 2018. Originally
approved in 1977. Last previous edition approved in 2013 as E618–07 (2013). DOI: Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
10.1520/E0618-07R18. 4th Floor, New York, NY 10036, http://www.ansi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E618 − 07 (2018)
3.1.5 surface-roughness average value (R )—the surface- 4.4 When measured as specified, the level of and changes in
a
roughness average value is the mean reading around which the surface roughness and the size of pieces produced are used to
needle tends to dwell or fluctuate under small amplitude when evaluate the machining performance of the metal being tested.
a continuously averaging meter is used. (Refer to 3.8.1.1 in
ANSI B46.1). The surface-roughness value obtained by a
5. Significance and Use
continuously averaging digital readout meter is acceptable.
5.1 This test method can be used to evaluate the machining
3.1.5.1 The surface-roughness recorded for each surface on
performance of a single grade or type of metal or to compare
thetestpieceisthemaximumofthesurface-roughnessaverage
one grade or type with another.
values measured on that surface at a minimum of four places
5.1.1 The machining performance of the test metal is
equispaced around the circumference and measured as de-
measured by the maximum rate at which test pieces can be
scribed in 3.1.5.
produced within specified surface roughness and dimensional
3.1.6 surface-roughness range (per set of samples)—the
limits for a specified length of time and also by the cutting
lowest and highest values of the surface roughnesses recorded
speed and tool feed employed to attain that rate.
for each surface as in 3.1.5.1for each set.
5.1.2 The relative machining performance of the various
metals tested using this test method may be evaluated only at
3.1.7 surface-roughness range (per test)—the lowest and
operating conditions that produce test pieces of like quality
highestvaluesofsurfaceroughnessesrecordedforeachsurface
with respect to surface roughness and dimensional limits for
as in 3.1.5.1 during the test.
comparable periods of machining time.
3.1.8 theoretical hourly production rate (in pieces per
hour)—3600 s/h divided by the cycle time in seconds per piece
6. Apparatus
diminished by: (1) the indexing time or high-speed time in
seconds per piece for a multiple-spindle machine, or (2) the 6.1 Automatic Screw Machine:
time in seconds per piece when no tools are cutting for a 6.1.1 A single-spindle automatic screw machine with a six-
single-spindle machine. or eight-hole turret, with adequate spindle capacity, and with
sufficient feed, speed, and power to machine a 1-in. round bar
3.1.9 tool feed rate—the distance traveled by the tool at a
of free-machining, alloy or high-strength steel, or
uniform rate divided by the number of spindle revolutions
6.1.2 A multiple-spindle automatic screw machine with a
during which this travel occurs. (Units: decimal inch or
spindle capacity and with sufficient feed, speed, and power to
decimal millimetre per revolution.)
machine 1-in. round bars of free-machining, alloy or high-
3.1.10 tool life (for a form tool)—the hours of machine time
strength steel simultaneously at all spindles.
determined from the calculated hourly production rate and the
6.2 Metal-Cutting Tools—On the basis of current use for
total number of test pieces produced from the start of the test
general applications for automatic screw-machine production,
to the earliest point at which the average of the recorded
two tool-steel grades (M7 for drills and M2 for form tools) are
surface-roughness average values or the average of sizes of the
suggested in 6.2.1 through 6.2.5. This is not intended to
test pieces in a sample set consistently exceed either the
preclude the use of other grades. This test method does require
surface-roughness limits or the size limits specified in 9.7.1,
that the use of tool materials, other than those suggested, be
9.7.2, and 9.7.3 for the piece diameter produced by that tool.
recorded and reported together with the reason(s) for the
3.2 Machining performance in this test method is evaluated
change.
by the following criteria: 3
6.2.1 A ⁄4-in. (19.05-mm) diameter or larger spot drill with
3.2.1 Tool life as described in 3.1.10.
a 90° included point angle may be used.
3 5
3.2.2 Cutting speed and tool-feed rate as described in 3.1.4
6.2.2 Two ⁄8-in. (9.52-mm) diameter and one ⁄8-in. (15.88-
and 3.1.9.
mm) diameter drills ground as specified in 8.6.
3.2.3 Hourly rate of production as described in 3.1.2 or
6.2.3 Either a dovetail or a circular rough-form tool of M2
3.1.8. steel designed as shown in Fig. 2.
3.2.4 A test sample set is described in 9.3. 6.2.4 Aflat, circular, or dovetail finish-form tool at least ⁄16
in. (14.29 mm) wide made from M2 steel as shown in Fig. 3.
6.2.5 A cutoff tool as described in 8.5.
4. Summary of Test Method
6.3 Stylus-Type Standard Commercial Surface-Roughness-
4.1 Astandard test piece, shown in Fig. 1, is machined from
Measuring Instrument, capable of measuring surface rough-
bar stock in an automatic screw machine.
ness in microinches arithmetic average (AA) and having a
4.2 Specified tools are used in a standard sequence to shape
stroke of at least ⁄4 in. (6.35 mm).
the test piece. Drills and form tools are used simultaneously to
6.3.1 In all cases an electric cutoff of 0.030 in. (0.8 mm) is
provide a typical machining condition during the test.
used. The stylus and skids of the tracer head must be
4.3 Cutting speed and tool feed rate for the metal being compatible with a 0.030-in. (0.8-mm) cutoff. (See 3.6.2 in
ANSI B46.1 for a definition of cutoff.)
tested are varied from one test run to another to determine the
maximum rate at which test pieces can be produced for the 6.3.2 The length of trace is the maximum possible on the
specified length of time without exceeding the specified limits surface being measured but must be at least 0.150 in. (3.81
for surface roughness and size dimensions. mm).
E618 − 07 (2018)
FIG. 1 Details of the ASTM Machinability Test Specimen and the Relative Positions of Form Tools
6.4 Micrometer(s), capable of indicating to 0.0001 in. or working tools, cams must be designed or selected to provide a
0.002 mm. uniform rate of tool feed for a distance greater than that
necessary to remove the required metal. This will ensure a
6.5 Toolmaker’s Microscope or equivalent.
uniform feed rate throughout the cut.
6.6 Commercially Available Coolant.
8.2 Feeds and speeds on the initial test run should be
selected on the basis of experience or general guide lines for a
7. Test Specimen
ferrous metal of similar composition and condition.
7.1 The test specimen detailed in Fig. 1 shall be machined
8.2.1 The positive stop pressure maintained during the test
from 1-in. (25.4-mm) diameter bars.
shall be that which is recommended by the machine tool
7.2 Different bar sizes may be used to produce a different
builder.
size test piece provided that the material removed and the
8.3 Place the cutting tools so they cut in the following
material remaining is in the same cross-sectional proportion as
sequence. The form tools and drills shall cut at the same time.
in the test piece shown in Fig. 1. When a different bar size is
8.3.1 Spot drill (optional).
used a proportionate change is made in all dimensions, except
8.3.2 Rough form and drill to depth with ⁄8-in. (15.88-mm)
that both formed surfaces must be at least ⁄8 in. (9.5 mm) long.
diameter drill.
This is to ensure accurate surface-roughness measurements.
8.3.3 Finish form to 0.875-in. (22.22-mm) outside diameter
11 3
7.3 When a different size test piece is used the bar size and
anddrill ⁄32in.(8.73mm)deepwiththefirst ⁄8-in.(9.52-mm)
test piece dimensions shall be recorded on the test report.
diameter drill.
8.3.4 Drill ⁄32 in. (8.73 mm) deep (through the cutoff) with
8. Procedure for Machine Setup
the second ⁄8-in. (9.52-mm) diameter drill.
8.1 Since there is a difference between automatic screw 8.3.5 An optional sequence of tooling for a single-spindle
machines as to how movement is conveyed to the end and side automatic machine uses only three drills in the turret; namely,
E618 − 07 (2018)
FIG. 2 Details of the Tool Edge for the ASTM Rough-Form Tool
5 3
one spot drill, one ⁄8-in. (15.88-mm) drill, and one ⁄8-in. 8.4.3 Grind and mount all form tools in the machine with an
(9.52-mm) drill with double indexing of the turret between effective positive top rake angle of 10°, a front clearance angle
successive drilling operations. of 5 to 12°, and, for the rough-form tool, a side-clearance angle
8.3.6 Cut off the finished piece. of 2 to 4°. Note any deviation from these angles found
necessary and record the reason. The grinding lay (direction of
8.4 Form Tool Conditions:
dominate linear surface texture) on the rake face of the rough
8.4.1 Using the most rigid cross-slide, set the rough-form
and finish form tools shall run parallel to the leading cutting
tool so that the part of the tool forming the 0.615 to 0.620-in.
edge. This is coincident with the practice of avoiding a slight
(15.62 to 15.75-mm) or minor diameter will cut on center.
negative lip rake angle.
8.4.2 Set the finish-form tool to cut the rough-formed 0.900
8.4.4 When the side-clearance angle for the rough-form
to 0.905-in. (22.86 to 22.99-mm) or major diameter on center
tools is obtained by a tilted tool holder, it is recommended that
and remove 0.030 in. (0.76 mm) from that diameter to form the
the rough-form tool be reground in a tool holder or fixture
0.870 to 0.875-in. (22.10 to 22.22-mm) diameter. When a
having an identical angle of tilt.
different size test piece is used, proportionately more or less
metal will be removed by the finish-form tool. 8.4.5 Allformtoolsmustbehardenedto63minimumHRC.
E618 − 07 (2018)
NOTE 1—Angle C: 10° positive back-rake angle when mounted in cutting position.
NOTE 2—Angle D: 5 to 12° clearance angle when mounted in cutting position.
FIG. 3 Details of the Tool Edge for the ASTM Finish-Form Tool
8.5 Cutoff Tool—An appropriate commercial tool shall be 9. Test Method
used.
9.1 Determine the reliability of machining-performance
8.6 Drills: data to be expected on any given machine by running machine-
8.6.1 Use solid two-flute standard length or screw-machine capability tests prior to a test program to d
...


NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: E618 − 07 (Reapproved 2018)
Standard Test Method for
Evaluating Machining Performance of Ferrous Metals Using
an Automatic Screw/Bar Machine
This standard is issued under the fixed designation E618; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
This test method was written to fill a requirement for a standard test for determining the
machinability of ferrous metals using automatic screw/bar machines. (Hereafter, these machines will
be referred to as automatic screw machines.) Although a variety of short-time laboratory tests have
demonstrated different machining characteristics among ferrous metals, it has been difficult to apply
the resulting data to commercial automatic screw machine practice.
In this test method a standard test piece is machined using tools and machining operations typical
of automatic screw machine practice.
Through the use of this test method, the relative machining performance of a metal can be evaluated
even though different automatic screw machines are used. Further, comparisons can be made among
different lots of the same grade or different grades to determine relative machining performance.
1. Scope ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
1.1 This test method covers a production-type test for
mendations issued by the World Trade Organization Technical
evaluating the machining performance of ferrous metals as
Barriers to Trade (TBT) Committee.
they are used in single-spindle or multiple-spindle automatic
screw machines. It is based on producing parts of a standard
2. Referenced Documents
design in such machines to uniform levels of quality with
2.1 ANSI Standard:
respect to surface roughness and size variation. The standard
B46.1 Surface Texture
test piece, designed for this test, is machined from bars using
a specified number of tools in a specified sequence. Nothing in
3. Terminology
this test method should be construed as defining or establishing
3.1 Definitions of Terms Specific to This Standard:
limits of acceptability for any grade or type of metal.
3.1.1 average surface roughness (per set of samples)—for
1.2 The values stated in inch-pound units are to be regarded
each surface (the major and minor diameter formed surfaces)
as standard. The values given in parentheses are mathematical
the surface roughness per set of samples is the average of the
conversions to SI units that are provided for information only
roughnesses recorded as in 3.1.5.1 for the six test pieces per
and are not considered standard.
set. A test set is described in 9.3.
1.3 This standard does not purport to address all of the
3.1.2 calculated hourly production rate (in pieces per
safety concerns, if any, associated with its use. It is the
hour)—3600 s/h divided by the cycle time in seconds per piece.
responsibility of the user of this standard to establish appro-
(Unit: pieces per hour.)
priate safety, health, and environmental practices and deter-
3.1.3 cycle time—the time in seconds per piece from bar
mine the applicability of regulatory limitations prior to use.
feed-out to bar feed-out, or from cutoff to cutoff, during
1.4 This international standard was developed in accor-
uninterrupted operation of the machine. It includes all stock,
dance with internationally recognized principles on standard-
machine, and tool movements.
3.1.4 surface speed—the product of the original bar circum-
1 ference (in feet or metres) and the spindle speed in revolutions
This test method is under the jurisdiction of ASTM Committee A01 on Steel,
Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee per minute. (Unit: ft/min or m/min.)
A01.15 on Bars.
Current edition approved Sept. 1, 2018. Published September 2018. Originally
approved in 1977. Last previous edition approved in 2013 as E618–07 (2013). DOI: Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
10.1520/E0618-07R18. 4th Floor, New York, NY 10036, http://www.ansi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E618 − 07 (2018)
3.1.5 surface-roughness average value (R )—the surface- 4.4 When measured as specified, the level of and changes in
a
roughness average value is the mean reading around which the surface roughness and the size of pieces produced are used to
needle tends to dwell or fluctuate under small amplitude when evaluate the machining performance of the metal being tested.
a continuously averaging meter is used. (Refer to 3.8.1.1 in
ANSI B46.1). The surface-roughness value obtained by a 5. Significance and Use
continuously averaging digital readout meter is acceptable.
5.1 This test method can be used to evaluate the machining
3.1.5.1 The surface-roughness recorded for each surface on
performance of a single grade or type of metal or to compare
the test piece is the maximum of the surface-roughness average
one grade or type with another.
values measured on that surface at a minimum of four places
5.1.1 The machining performance of the test metal is
equispaced around the circumference and measured as de-
measured by the maximum rate at which test pieces can be
scribed in 3.1.5.
produced within specified surface roughness and dimensional
3.1.6 surface-roughness range (per set of samples)—the
limits for a specified length of time and also by the cutting
lowest and highest values of the surface roughnesses recorded
speed and tool feed employed to attain that rate.
for each surface as in 3.1.5.1for each set.
5.1.2 The relative machining performance of the various
metals tested using this test method may be evaluated only at
3.1.7 surface-roughness range (per test)—the lowest and
operating conditions that produce test pieces of like quality
highest values of surface roughnesses recorded for each surface
with respect to surface roughness and dimensional limits for
as in 3.1.5.1 during the test.
comparable periods of machining time.
3.1.8 theoretical hourly production rate (in pieces per
hour)—3600 s/h divided by the cycle time in seconds per piece
6. Apparatus
diminished by: (1) the indexing time or high-speed time in
6.1 Automatic Screw Machine:
seconds per piece for a multiple-spindle machine, or (2) the
time in seconds per piece when no tools are cutting for a 6.1.1 A single-spindle automatic screw machine with a six-
or eight-hole turret, with adequate spindle capacity, and with
single-spindle machine.
sufficient feed, speed, and power to machine a 1-in. round bar
3.1.9 tool feed rate—the distance traveled by the tool at a
of free-machining, alloy or high-strength steel, or
uniform rate divided by the number of spindle revolutions
6.1.2 A multiple-spindle automatic screw machine with a
during which this travel occurs. (Units: decimal inch or
spindle capacity and with sufficient feed, speed, and power to
decimal millimetre per revolution.)
machine 1-in. round bars of free-machining, alloy or high-
3.1.10 tool life (for a form tool)—the hours of machine time
strength steel simultaneously at all spindles.
determined from the calculated hourly production rate and the
6.2 Metal-Cutting Tools—On the basis of current use for
total number of test pieces produced from the start of the test
general applications for automatic screw-machine production,
to the earliest point at which the average of the recorded
two tool-steel grades (M7 for drills and M2 for form tools) are
surface-roughness average values or the average of sizes of the
suggested in 6.2.1 through 6.2.5. This is not intended to
test pieces in a sample set consistently exceed either the
preclude the use of other grades. This test method does require
surface-roughness limits or the size limits specified in 9.7.1,
that the use of tool materials, other than those suggested, be
9.7.2, and 9.7.3 for the piece diameter produced by that tool.
recorded and reported together with the reason(s) for the
3.2 Machining performance in this test method is evaluated
change.
by the following criteria: 3
6.2.1 A ⁄4-in. (19.05-mm) diameter or larger spot drill with
3.2.1 Tool life as described in 3.1.10.
a 90° included point angle may be used.
3 5
3.2.2 Cutting speed and tool-feed rate as described in 3.1.4
6.2.2 Two ⁄8-in. (9.52-mm) diameter and one ⁄8-in. (15.88-
and 3.1.9.
mm) diameter drills ground as specified in 8.6.
3.2.3 Hourly rate of production as described in 3.1.2 or 6.2.3 Either a dovetail or a circular rough-form tool of M2
3.1.8. steel designed as shown in Fig. 2.
6.2.4 A flat, circular, or dovetail finish-form tool at least ⁄16
3.2.4 A test sample set is described in 9.3.
in. (14.29 mm) wide made from M2 steel as shown in Fig. 3.
6.2.5 A cutoff tool as described in 8.5.
4. Summary of Test Method
6.3 Stylus-Type Standard Commercial Surface-Roughness-
4.1 A standard test piece, shown in Fig. 1, is machined from
Measuring Instrument, capable of measuring surface rough-
bar stock in an automatic screw machine.
ness in microinches arithmetic average (AA) and having a
4.2 Specified tools are used in a standard sequence to shape
stroke of at least ⁄4 in. (6.35 mm).
the test piece. Drills and form tools are used simultaneously to
6.3.1 In all cases an electric cutoff of 0.030 in. (0.8 mm) is
provide a typical machining condition during the test.
used. The stylus and skids of the tracer head must be
compatible with a 0.030-in. (0.8-mm) cutoff. (See 3.6.2 in
4.3 Cutting speed and tool feed rate for the metal being
tested are varied from one test run to another to determine the ANSI B46.1 for a definition of cutoff.)
maximum rate at which test pieces can be produced for the 6.3.2 The length of trace is the maximum possible on the
specified length of time without exceeding the specified limits surface being measured but must be at least 0.150 in. (3.81
for surface roughness and size dimensions. mm).
E618 − 07 (2018)
FIG. 1 Details of the ASTM Machinability Test Specimen and the Relative Positions of Form Tools
6.4 Micrometer(s), capable of indicating to 0.0001 in. or working tools, cams must be designed or selected to provide a
0.002 mm. uniform rate of tool feed for a distance greater than that
necessary to remove the required metal. This will ensure a
6.5 Toolmaker’s Microscope or equivalent.
uniform feed rate throughout the cut.
6.6 Commercially Available Coolant.
8.2 Feeds and speeds on the initial test run should be
selected on the basis of experience or general guide lines for a
7. Test Specimen
ferrous metal of similar composition and condition.
7.1 The test specimen detailed in Fig. 1 shall be machined
8.2.1 The positive stop pressure maintained during the test
from 1-in. (25.4-mm) diameter bars.
shall be that which is recommended by the machine tool
7.2 Different bar sizes may be used to produce a different
builder.
size test piece provided that the material removed and the
8.3 Place the cutting tools so they cut in the following
material remaining is in the same cross-sectional proportion as
sequence. The form tools and drills shall cut at the same time.
in the test piece shown in Fig. 1. When a different bar size is
8.3.1 Spot drill (optional).
used a proportionate change is made in all dimensions, except
8.3.2 Rough form and drill to depth with ⁄8-in. (15.88-mm)
that both formed surfaces must be at least ⁄8 in. (9.5 mm) long.
diameter drill.
This is to ensure accurate surface-roughness measurements.
8.3.3 Finish form to 0.875-in. (22.22-mm) outside diameter
11 3
7.3 When a different size test piece is used the bar size and
and drill ⁄32 in. (8.73 mm) deep with the first ⁄8-in. (9.52-mm)
test piece dimensions shall be recorded on the test report.
diameter drill.
8.3.4 Drill ⁄32 in. (8.73 mm) deep (through the cutoff) with
8. Procedure for Machine Setup
the second ⁄8-in. (9.52-mm) diameter drill.
8.1 Since there is a difference between automatic screw 8.3.5 An optional sequence of tooling for a single-spindle
machines as to how movement is conveyed to the end and side automatic machine uses only three drills in the turret; namely,
E618 − 07 (2018)
FIG. 2 Details of the Tool Edge for the ASTM Rough-Form Tool
5 3
one spot drill, one ⁄8-in. (15.88-mm) drill, and one ⁄8-in. 8.4.3 Grind and mount all form tools in the machine with an
(9.52-mm) drill with double indexing of the turret between effective positive top rake angle of 10°, a front clearance angle
successive drilling operations. of 5 to 12°, and, for the rough-form tool, a side-clearance angle
8.3.6 Cut off the finished piece. of 2 to 4°. Note any deviation from these angles found
necessary and record the reason. The grinding lay (direction of
8.4 Form Tool Conditions:
dominate linear surface texture) on the rake face of the rough
8.4.1 Using the most rigid cross-slide, set the rough-form
and finish form tools shall run parallel to the leading cutting
tool so that the part of the tool forming the 0.615 to 0.620-in.
edge. This is coincident with the practice of avoiding a slight
(15.62 to 15.75-mm) or minor diameter will cut on center.
negative lip rake angle.
8.4.2 Set the finish-form tool to cut the rough-formed 0.900
8.4.4 When the side-clearance angle for the rough-form
to 0.905-in. (22.86 to 22.99-mm) or major diameter on center
tools is obtained by a tilted tool holder, it is recommended that
and remove 0.030 in. (0.76 mm) from that diameter to form the
the rough-form tool be reground in a tool holder or fixture
0.870 to 0.875-in. (22.10 to 22.22-mm) diameter. When a
having an identical angle of tilt.
different size test piece is used, proportionately more or less
metal will be removed by the finish-form tool. 8.4.5 All form tools must be hardened to 63 minimum HRC.
E618 − 07 (2018)
NOTE 1—Angle C: 10° positive back-rake angle when mounted in cutting position.
NOTE 2—Angle D: 5 to 12° clearance angle when mounted in cutting position.
FIG. 3 Details of the Tool Edge for the ASTM Finish-Form Tool
8.5 Cutoff Tool—An appropriate commercial tool shall be 9. Test Method
used.
9.1 Determine the reliability of machining-performance
8.6 Drills: data to be expected on any given machine by running machine-
8.6.1 Use solid two-flute standard length or screw-machine capability tests prior to a test program to determine the
length high-speed steel twist drills. Note any deviati
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