Posted by BillS on February 07, 2006 at 15:53:23:
In Reply to: Definition of backlash posted by Steve Chen on February 05, 2006 at 15:18:05:
Why would a base circle be easier to specify or measure backlash? In a normal gear set where OD=(T+2)/NDP, the base circle is below the root diameter, right? I'm probably missing the point you were making...
Admittedly, a pitch circle is imaginary also, but an error in backlash measurement should be insignificant it you picked a contact point halfway up the tooth for a dial gage.
How about an offset contact anvil for the dial ind. that's ground as half a rack form with correct PA would be easier to visually set into place?