Posted by Ron V on August 11, 2008 at 20:39:16:
In Reply to: ANNUAL INSIDE DIAMETER posted by Shahzad on August 11, 2008 at 16:51:42:
Standard internal minor diameter of an annulus should be (Z-2) x Module, where Z is the number of teeth.
Add to that: Usually internal tooth forms are given a default addendum correction of -0.40.
Without corrections, the 71 teeth 6 module profile should have an internal minor diameter of 414.00mm. With the minus correction it would be 418.80.