Summary for geometric tolerancing Discussion
Geometric tolerancing is not a plating-only concept; it is a broader engineering practice used to specify allowable variation in the form, orientation, and relationship of manufactured features. In response to Paul Millar’s question, Richard Guise explains that many parts carry geometric tolerances, such as concentricity between two shaft diameters, and notes that the symbols are widely used and fairly universal. He suggests checking an engineering drawing textbook, a library, or reference catalogs. Another answer points to standard references on the subject, especially ASME Y14.5, the main industry standard for dimensioning and tolerancing, and mentions books such as David A. Madsen’s Geometric Dimensioning and Tolerancing. The thread’s practical takeaway is that geometric tolerancing is a general design/drawing discipline, not a special plating term.
Q. Please help I’m trying to access any definitions possible for Geometric Tolerancing? I’m under the impression that it pertains to the special considerations involved when plating unusual pieces to be plated……..? Can anyone please either concur or further define this topic?
Geometric Tolerancing? Thanks……
Paul Millar
Canada
1998
A. Paul,
Lots of manufactured parts have geometric tolerances, it isn’t just for plated parts, for example tolerances of concentricity between two diameters on a shaft. Its pretty common most of the symbols are universal I would of thought any engineering drawing textbook would have details, in fact I think I saw one in the Hanser Gardener catalogue or even your local library.
Regards
Richard Guise
– Lowestoft, U.K.
A. There are many references to Geometric Dimensioning and Tolerancing out there. The best reference is ASME Y14.5 Standard for Dimensioning and Tolerancing (American Society of Mechanical Engineers) [on
AbeBooks, or
eBay,
or
affil links]
. This is the recognized standard for geometric tolerancing in the United States – though some other countries use the ISO standard. ASME Y14.5 is a legally defensible document for applying geometric tolerances.
The standard contains information also on plating and coated parts. There are also excellent text books and training materials out there – such as: Geometric Dimensioning and Tolerancing by David A. Madsen (published by Goodheart-Wilcox Company) ⇨
Connie Dotson
– Canton, Michigan
A. Paul: Geometric dimensioning and tolerancing refers to symbols and allowances that control an object’s form, profile, orientation, location and runout. It’s found on drawings in the form of a block containing (first) the symbol (14 basic) including concentricity, perpendicularity, angularity, total runout, etc., and a second box containing a tolerance and (possibly) a modifier – such as a Dia. symbol or Maximum Material Condition – MMC, and (depending on the case) a third – or more – box(es) referring to the datum(s).
Daren Lawrence
– Milford, New Hampshire, USA