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Ted Mooney, P.E. RET
Pine Beach, NJ
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for Metal Finishing since 1989
Confusing ASTM B650 for plating thickness
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Q. I can't figure it out. I have a requirement to plate a rod to ASTM B650 Class 125. Dimensions on the print are after plating. I need to make allowance for the plating thickness when machining the rod, but ASTM B650 doesn't state what Class 125 thickness is.
ASTM B650 (2002) states plating thickness for Class 1 and Class 2 only in section 4.1. I have a print requirement for Class 125. ASTM B650 section 6.5 Thickness says go to "section 3 (see 7.2)", and section 3 is Terminology, and para 7.2 is Test Methods-Thickness. No specific thickness requirement for Class 125 is defined.
How is the average adult supposed to figure out what Class 125 thickness is? Was this changed in the 2002 version? Is it covered in ASTM B374 per 3.2?
Manufacturing - Stuarts Draft, Virginia
2006
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A. ASTM B650, Class 125 thickness is 125 microns, minimum. - Goleta, California 
Finishing.com honored Ken for his countless carefully researched responses. He passed away May 14, 2015.Rest in peace, Ken. Thank you for your hard work which the finishing world, and we at finishing.com, continue to benefit from. A. My guess is that the specification is supposed to be "Class 1 25" meaning Class 1, 25 micrometers. This is a very common thickness for hard chrome. 2.5 micrometers is too thin for many wear applications. Toby PadfieldAutomotive module supplier - Michigan |
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