ASME Y14.5-2009 Update PDF Print E-mail


There are lots of changes to the standard, many of which are insignificant (notice the "M" is missing after the Y14.5 – the standard is still equally useful with metric or conventional inch dimensioning), but several changes are important.


One thing that those familiar with the 1994 version of the standard will notice is that flatness can now "legally" be applied to a feature of size; there's no longer a need to use straightness to control the flatness of a center plane on a washer or slot, for example, and so the MMC modifier can be used with flatness when it's applied to a feature of size. It's still illegal, of course, to use an MMC modifier on flatness applied to a surface.



2009 UPDATE ONSITE A shortened version of our 3-day Fundamentals of GD&T is available for customers who have previously had training in ASME Y14.5M-1994 and need to get a refresher of some of the trickier aspects of Y14.5 plus see all of the updates.


ASME Y14.5-2009 Cover



For a limited time, any customer needing to update skills on the new 2009 standard for a group who has had training or who has extensively used ASME Y14.5M-1994 can arrange to have a special 2-day 2009 Update Class.

Topics include: tolerance calculations; boundary conditions; new definitions: (irregular feature of size, related vs. unrelated envelope, non-uniform boundary, MMB (maximum material boundary), LMB (least material boundary), RMB (regardless of material boundary); new symbols: spotface, continuous feature, moveable datum target, translation, unequally disposed profile, all over, independency; and other changes, including: MMB modifier allowed on a surface, flatness of a feature of size, new use for tangent plane modifier, clarification of datum examples and degrees of freedom.


In addition to the new topics covered from the 2009 standard, the course will also be an excellent refresher, covering all the rules and symbols from the 1994 standard as well.


Call for a free quote via phone: (586) 693-0219 or email: This e-mail address is being protected from spambots. You need JavaScript enabled to view it . We'll need to know an approximate number of trainees, the location, and desired dates.