Posted by: newton ® 06/21/2007, 08:44:14 Author Profile eMail author Edit

can the concentricity be defined with 2 datum features which are perpendicular in nature? or Is it possible to define the concentricity as shown in the example attached herewith? If yes please explain me, how? Thank you in advance....

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Re: doubt in Concentricity (GD&T)
Re: doubt in Concentricity (GD&T) -- newton	Post Reply	Top of thread	Forum

Posted by: Kelly Bramble ® 06/21/2007, 09:09:43 Author Profile eMail author Edit

You could, however the "B" datum does not do anything (help) to orient the datum reference frame (Origin). The origin (datum) would be established in the order of "A" then "B". So, the highest areas of contact would be established on datum "A" by using a cylinder collapsed onto the datum A's highest areas then datum B would be established by moving a planar datum simulator which is oriented perpendicular the datum axis A until the highest contact area of the datum surface contacts the simulator. With all this said all datum B would do is locate the datum origin at the intersection of the cylinder datum A and the perpendicular surface datum "B". Measuring for Concentricity is just an average of the opposed surface elements as one rotates about a coaxial datum axis. So, in summary, Datum B doesn't hurt or help.. BTW, it is sooooooo helpfull when folks post pictures! Modified by Kelly Bramble at Thu, Jun 21, 2007, 09:11:35

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