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- C-9 Cast Microfinish Comparator
Individually Serialized, Calibrated & Certified Microfinish Comparators come with a Certificate of Calibration.
Measuring Conditions are listed with their corresponding values.
The calibrating system was calibrated to Standard Reference Material traceable to the National Institute of Standards and Technology. Calibrations are performed by Holts Precision inc.
Cast Microfinish Comparator: Nine replicated cast surface finish specimens ranging from 20 to 900 microinches.
The C-9 Cast MICROFINISH COMPARATOR Surface Roughness Scale is made by a dual electroforming process wherein nickel is electrodeposited to provide an exact reproduction in intricate detail.The same electroforming process used to produce the Surface Roughness Scale is available from GAR Electroforming to serve your product needs.
The C-9 Cast MICROFINISH COMPARATOR Surface Roughness Scale provides industry with established flat surface roughness specimens for visual and tactual comparison. It is used in specifying and controlling surface roughness when a product having the appearance of typically cast surfaces is required.
The C-9 Cast MICROFINISH COMPARATOR Surface Roughness Scale provides an economical tool which permits roughness to be specified on the same basis as linear measurements. The surfaces presented are the result of years of research and engineering. Details covering this subject are now published in The American National Standards Institute (ANSI) specification titled: "Surface Texture, Surface Roughness, Waviness and Lay." ANSI/ASME B46.1
UNIFORMITY AND ACCURACY
The original masters and the electroformed replica production masters have been checked at evenly distributed intervals. Sufficient measurements were taken to determine a representative average. The rating listed is the average of these readings.This MICROFINISH COMPARATOR Surface Roughness Scale is a patented item and is a product of the engineering skill and precision workmanship of GAR Electroforming Division.
The C-9 Cast MICROFINISH COMPARATOR is rectangular in shape (4 1/2"x 3 1/4") and is a corrosion resistant electroformed nickel duplicate of actual cast surfaces.
There are nine replicated cast surface finish specimens ranging from 20 to 900 microinches.
The C-9 MICROFINISH COMPARATOR is supplied in a leatherette case with engineering data and instructions.
The C-9 is also available in metric with micrometer designations.
The specimens are electroformed replicas of original cast surfaces.
This MICROFINISH COMPARATOR Surface Roughness Scale is made of nickel. It will not corrode.
Each specimen has the surface roughness characteristics of a cast metallic material.
It is recognized that the RMS roughness designation which specifies the required finish of a part in micro-inch (millionths of an inch) and is the average amount by which the finish may vary from the nominal surfaces is not a satisfactory method of specifying cast finishes.
The RMS designation reflects the tool marks which are more or less constant across a surface while the casting reflects one or more of the following:
A. The grain size of the cooling metal surface.
B. The sand grain size of the mold.
C. The grain size of the ceramic wash on the steel mold.
D. The grain size of the ceramic investment mold.