ASTM D6205-98
(Practice)Standard Practice for Calibration of the James Static Coefficient of Friction Machine
Standard Practice for Calibration of the James Static Coefficient of Friction Machine
SCOPE
1.1 This practice covers the testing of the James Machine for reprocucibility and repeatability of static coefficient of friction, relative to a standard reference interface consisting of the working surfaces of Borco board and standard leather shoe sole material. The practice provides basis data on the stability of the James Machine to ensure accurate static coefficient of friction determinations over time and repeated use and for determining if the James Machine is mechanically calibrated and properly aligned.
1.2 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 and health practices and determine the applicability of regulatory limitations prior to use.
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Designation:D6205–98
Standard Practice for
Calibration of the James Static Coefficient of Friction
Machine
This standard is issued under the fixed designation D 6205; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope Chrome Tanned, Impregnated, and Soles
1.1 This practice covers the testing of the James Machine
3. Terminology
for reproducibility and repeatability of static coefficient of
3.1 Definitions: For general definitions, see Test Method
friction, relative to a standard reference interface consisting of
2 D 2047 and Terminology D 2825.
theworkingsurfacesofBorco boardandstandardleathershoe
3.1.1 James Static Coeffıcient of Friction (JSCOF),
sole material. The practice provides basis data on the stability
n—static coefficient of friction as measured by the James
of the James Machine to ensure accurate static coefficient of
machine in accordance with Test Method D 2047.
friction determinations over time and repeated use and for
3.2 Definitions of Terms Specific to This Standard:
determining if the James Machine is mechanically calibrated
3.2.1 Borco, n—special 5-ply vinyl drawing board cover.
and properly aligned.
3.2.2 reference surface, Borco standard leather system,
1.2 This standard does not purport to address all of the
n—working interface of the set consisting of the white side of
safety concerns, if any, associated with its use. It is the
the Borco material, mounted as described in this practice, and
responsibility of the user of this standard to establish appro-
the standard leather shoe sole material, mounted on a precision
priate safety and health practices and determine the applica-
shoe pad as described in this practice.
bility of regulatory limitations prior to use.
3.2.3 standard test sequence, n—seriesofnotlessthaneight
2. Referenced Documents consecutive James Static Coefficient of Friction (JSCOF)
determinations made on the Borco/standard leather system in
2.1 ASTM Standards:
accordance with this practice.
D 2047 Test Method for Static Coefficient of Friction of
Polish-Coated Floor Surfaces as Measured by the James
4. Summary of Practice
Machine
4.1 The performance of the James Machine, in the standard
D 2825 Terminology Relating to Polishes and Related Ma-
3 configuration for the determination of James Static Coefficient
terials
of Friction (JSCOF), is tested relative to a standard working
E 29 Practice for Using Significant Digits in Test Data to
4 interface consisting of the surface of white Borco material in
Determine Conformance with Specifications
4 contact with a standard leather shoe pad. The static coefficient
E 178 Practice for Dealing with Outlying Observations
4 of friction values generated provide a basis to establish the
E 456 Terminology Relating to Quality Statistics
reproducibility and repeatability of the mechanical configura-
2.2 Federal Specification:
tion of the James Machine and determine whether the machine
KK-L-165C Leather, Cattlehide, Vegetable Tanned and
remains within the calibration limits.
5. Significance and Use
5.1 This practice is used to calibrate the James Machine for
determination of static coefficient of friction of polish surfaces
This practice is under the jurisdiction of ASTM Committee D-21 on Polishes
and is the direct responsibility of Subcommittee D21.06 on Slip Resistance.
in accordance with Test Method D 2047. Over considerable
Current edition approved Jan. 10, 1998. Published July 1998.
time and repeated use the James Machine tends to become
Borco is a registered trademark for a Danish product imported into the United
somewhat mechanically out of calibration, giving self-evident
States by Sierra Group, a division of Wallace Leisure Products, Inc.Available from
Papyro-TexA/S, DK-2730, Herlev, Denmark; distributed in NorthAmerica through
drafting and office supply stores under the trade names “Borco,” “Vyco,” and
“Altex” board covers.
3 5
Annual Book of ASTM Standards, Vol 15.04. Available from Standardization Documents Order Desk, Bldg 4 Section D, 700
Annual Book of ASTM Standards, Vol 14.02. Robbins Ave., Philadelphia, PA 19111-5094, Atten: NPODS.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D6205–98
anomalous JSCOF readings. The periodic accumulation and 6.1.6 Test Table not Level—This problem is usually caused
comparison of data generated by this practice provides an by normal wear of the table transport guides, but it may also
indication of when the machine is no longer within the result from an impact on the table or improper use of the test
calibration limits and can no longer be expected to provide table for storage. A test table which is not level will result in
accurate and reliable data. abnormal JSCOF readings. The deviation from accurate
JSCOF readings will depend on the magnitude and direction of
the deviation of the test table from level.
6. Interferences (Troubleshooting)
6.1.7 Excess Play or Movement in the Strut Rack Gear—
6.1 Deviations in calibration data and anomalies in machine
This results from wear in the strut rack and pinion gear
reproducibility and repeatability are due to the following
assembly, loss of lubricant, or use of an improper lubricant in
interferences:
the gear box. Care must be taken that there is enough freedom
6.1.1 Contamination of the Test Surfaces—These are most
in the movement of the strut rack gear so that the vertical
commonly due to fingerprints or other soils on the working
motion of the strut rack gear is not impeded. Excess play in a
leather surface or the working surface of the Borco board, or
direction either parallel or perpendicular to the plane of normal
the presence of residual materials on the Borco board from use
motion of the strut (or in any direction perpendicular to the
of an improper cleaning solution. Generally, contamination of
vertical motion of the strut rack gear) will result in low JSCOF
the working surfaces will result in low JSCOF readings.
readings.
6.1.2 Irregular Test Table Transport—This problem is most
6.1.8 Test Table Travel is not Orthogonal to the Plane of
common on James Machines that derive test table transport
Strut Motion—This is usually caused by excessive movement
from manual cranking, which may not be smooth and uniform,
in the strut rack gear assembly in a direction perpendicular to
but it may also be caused by grit and dirt in the drive
the plane of normal strut motion (see 6.1.7), binding or
mechanism or on the transport guides of the test table. Test
excessive movement in at least one of the upper strut pivots
table movement that is not smooth and uniform will provide
(see 6.1.4), or normal wear or misalignment of the test table
low JSCOF readings.
transport guides (see 6.1.6). This problem results in low
6.1.3 Improper Rate of Test Table Transport—Even when
JSCOF readings, since the slipping motion of the shoe pad on
uniform, the use of an improper rate of test table transport will
the test surface is compounded by a skewing action (greater
result in changes in the JSCOF. This is most often seen in
lateral forces are applied at the interface than are recorded by
manually cranked test table transports, where the rate of travel
the linear table displacement shown on the JSCOF chart).
is difficult to judge subjectively. Many motor driven test tables
6.1.9 Chart Board (or JSCOF Chart) is not in a Plane
have an electrical motor speed control which adjusts the rate of
Parallel to the Plane of the Strut Motion—This problem is
table travel, and this can be inadvertently moved out of
usuallyduetoaheavyimpactonthechartboard,butitcanalso
adjustment.Too rapid a rate of travel will result in high JSCOF
be due to the use of a pad of JSCOF charts (rather than an
readings, and too slow a rate of travel will result in low
individual sheet) attached to the chart board. The magnitude
readings.
and sign of deviations in JSCOF readings that result from this
6.1.4 Wear or Binding—Wear or binding at the following
problem depend on the magnitude and direction of the devia-
bearing surfaces will result in deviations from calibration and
tion of the chart board references planes from a parallel
loss of machine repeatability: upper strut pivot, upper strut ball
configuration with respect to the plane of strut motion.
bearings,backplate,strutrackandpiniongearassembly,lower
6.1.10 Warped, or “Out of True” Back Plate, Chart Board,
strut pivot, and shoe pad cups for lower strut pivots. These
Strut Arm, or Strut Rack Gear—Though this problem can be
problems are most often the result of the normal, repeated use
the result of heavy impact, it is most commonly the result of
of the James Machine, but they can also be caused by heavy
not maintaining the James Machine in a controlled temperature
impacts, improper use, improper periodic cleaning and lubri-
environment. The James Machine is a complex assembly of
cation, or inadequate protection of the machine from dirt.Wear
parts that are rigidly held in alignment by bead welds or bolts.
resulting in excessive play in the bearing surfaces will results
Since many of the parts are constructed of different metals,
in lower JSCOF readings. Sporadic binding of the bearing
temperature changes (and the different coefficients of thermal
surfaces and pivot points will result in loss of machine
expansion) will result in very large forces being applied to the
reproducibility and repeatability. Consistent binding of the
joints or to the components themselves. This can result in a
bearing or pivot surfaces can result in high JSCOF readings.
distortion or warping of the parts, particularly those which are
6.1.5 Test Table not Flat—Test tables are warped out of
large or have at least one long dimension.
flatness by either heavy impacts onto the table, storage of
heavy items on the edges of the test table, or storage of the
7. Apparatus
JamesMachinewiththeweightandstrutintheuprightposition 6,7
7.1 James Machine —See Fig. 1.
resting on the test table. This practice does not test for flatness
of the test table, and this property must be independently
assessed, either visually or by use of a machinist’s dial gage
ThesolesourceofsupplyoftheJamesMachineknowntothecommitteeatthis
attached to the strut rack gear to test the traversing test table.
time is Quadra, Inc., 1833 Oakdale Ave., Racine, WI 53405; (414)-637-6525.
Lack of adequate test table flatness will result in poor repro-
Machine shop-drawings for the construction of the James machine are available
ducibility of data as a function of the test specimen (tile)
from Chemical Specialities Manufacturers Association, 1913 Eye Street, NW,
placement on the table. Washington, DC 20006; (202)-872-8110.
D6205–98
a—Weights
b—Cushion
c—JSCOF Chart
d—Chart Board
e—Spring Clip
f—Recording Pencil
g—Set Screw
h—Strut Arm
i—Specimen
j—Shoe Pad
k—Test Table
l—Retaining Bar
m—Back Plate
n—Upper Strut Pivot and Ball Bearing Rollers
o—Gear Box (Rack and Pinion Gear, Strut Rack Gear)
p—Upper Strut
q—Lower Strut
r—Lower Strut Pivot and Shoe Pad Pivot Cups
s—Transport Guides
FIG. 1 James Machine
D6205–98
,
7 8
7.2 Standard Reference Leather —Leather sole material pad when the strut is in the full upright position and the test
conforming to Federal Specification KK-L-165C (Type 1, table is in the start position. The shoe pad stop end shall be
Class 6). constructed so that it contacts only the machined shoe pad and
7.3 Leather/Shoe Pad Assembly—Reference leather not the leading edge of the leather. See Fig. 2. The shoe pad
mounted on the machined shoe pad. stop prevents slippage of the shoe pad during movement of the
7.4 Borco Board —drafting and drawing board working test table during calibration of the James Machine.
surface cover. 7.10 Drafting Tape.
,
7 9
7.5 Reference Surface —Aluminum plate, 30.48 by 30.48 7.11 Machinist’s Square.
by 0.3175 cm (12 by 12 by 0.125 in.), which has been
machinedflat,towhich30.48by30.48cm(12by12in.)Borco 8. Test Surface
board has been mounted, white side up.
8.1 For James Machine calibration the test surface assembly
,
7 10
7.6 JSCOF Chart.
will consist of the working interface between the standard
7.7 Cleaner Solution—Alcohol and water-based cleaner
reference leather, mounted on the shoe pad, and the mounted
that does not leave a non-volatile residue, such as household
Borco board reference surface.
window glass cleaner, or equivalent.
8.2 The test surfaces shall not be altered, adulterated, or
7.8 Cleaning Cloth—Clean, lint-free, absorbent cloth or
contaminated in any matter, except for the cleaning procedure
white paper towel.
which begins each test sequence. When not in use, the
7.9 Shoe Pad Stop—Metal block, approximately 15 cm (6
referencesurfaceandleather/shoepadassemblyshallbestored
in.) wide and long enough to fit between the James Machine
in individual, sealed, dust-proof plastic bags, and protected
test table retaining bar and the leading edge of the metal shoe
from impacts, contamination, and scratches.
9. Procedure
If you aware of alternative suppliers, please provide this information toASTM
9.1 Preliminary:
Headquarters.Your comments will receive careful consideration at a meeting of the
9.1.1 Remove the reference surface from its protective
responsible technical committee, which you may attend.
Thesolesourceofsupplyofstandardreferenceleatherknowntothecommittee plastic bag.
at this time is Parsons Tanning Co., 333 Skokie Blvd., Suite 105, Northbrook, IL
9.1.2 Clean the bottom aluminum surface and the Borco
60062. RequestType 1, Class 6. Precut leather, ready to mount on the test shoe pad,
surface with cleaning solution and a clean, lint-free cloth or
isavailablefromChemicalSpecialitiesManufacturersAssociation,1913EyeStreet,
soft paper towel. Wipe dry and set the clean reference surface
NW, Washington, DC 20006; (202)-872-8110.
The sole source of supply of a mounted reference surface known to the
asideinadust-freeenvironmenttothoroughlydry(donotheat)
committee at this time isTechnical Products Co., 264 ParkAvenue, North Caldwell,
for a minimum of 30 min before using it in the test procedure.
NJ 07006.
10 Do not touch the cleaned reference surface or allow it to
The sole source of supply of a JSCOF Chart known to the committee at this
contact other objects.
time is Chemical Specialities Manufacturers Association, 1913 Eye Street, NW,
Washington, DC 20006; (202)-872-8110.
9.1.3 Remove the leather /shoe pad assembly from i
...
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