1. Tolerance Calculations Basic Hole System

2. Tolerances The Basic Hole System of calculating tolerances is based on using standard reamers, broaches, and other standard tools to produce holes. Shafting is machined to any size desired. The minimum hole size is taken as the basic size and tolerances are applied to both the shaft and hole. Given the following specifications find the limit dimension for both the shaft and the hole using the “Basic Hole System”

3. Tolerances Using the American National Standard Running and Sliding Fits table cross reference the nominal hole size (2.00) with the Standard Limits values (RC8)

4. Tolerances Convert the numbers to thousands by moving the decimal point 3 places to the left or dividing the numbers 1000.

5. Tolerances • Add or subtract the values to the nominal size to find the upper and lower limits dimensions of the hole and shaft • Hole Shaft • The limits dimension for the hole diameter is (2.0000-2.0045) and the limits dimension for the shaft is (1.9910-1.9940).

6. Tolerances • The minimum allowance is the difference between the smallest hole and the largest shaft. • Minimum Allowance 2.0000 Smallest Hole -1.9940 Largest Shaft 0.0060 Minimum Allowance

7. Tolerances • The maximum allowance is the difference between the largest hole and the smallest shaft. • Maximum Allowance 2.0045 Largest Hole -1.9910 Smallest Shaft 0.0135 Maximum Allowance