Posted by Zachary Young on June 06, 2002 at 14:05:35:
I have a customer drawing which calls out a spline tooth .001 true position to a primary datum (1.460 dia)which has an axis perpendicular to centerline and a secondary datum (dia) which is adjacent to the spline. My first question is how do you apply a true position tolerance to a spline tooth, and is it proper to do so. My interpretation would be that a composite tolerance accumulating symmetry,angular location, lead error and taper would somehow be applied to evaluate for true position. My second question would be how on earth would you check such a thing? The spine is a 42 tooth,80/160 DP, 45 deg PA per ANSI B92.1-1970 side fit CL 5. The STD PD is .525. To further complicate things, neither datums are finished and the customer is asking us to locate the tooth using two ground surfaces on the top face of the primary datum (1.460 dia). I'm attempting to explain to the customer that if we are allowed .001 @ the PD (.525), then we are allowed .00278 @ 1.460, but they insist that we are only allowed .001, regardless of the distance we are checking over. I arrived at .00278 by the following method- sin-1(.001/PD)= angle(dec) then 1.460 X sin angle = opposite. If anyon ecan offer me any counsel as to the proper method to check this requirement, please let me know. Your knowledge and expertise is greatly appreciated.
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