The 10% product tolerance rule is commonly used in the manufacturing
industry. It is considered a "rule-of-thumb" which means
that it is a suggestion or a starting point. You, as the engineer,
may use the 10% product tolerance rule, or deviate from the 10%
product tolerance rule, as long as you can justify your decision
to your management.
To calculate the gage tolerance using the 10% product tolerance
rule:
1. Calculate the full tolerance of the product feature.
2. Calculate 10% of the product feature tolerance to find the
full gage tolerance.
3. Divide the full gage tolerance in half to find the gage member
tolerance.
(Otherwise stated: Product Tolerance x 0.05 = Gage Member Tolerance)
