Final answer:
When a grinding stone wears down, it is important to adjust the tool rest to within a certain distance of an inch, such as within 1/16 of an inch.
Step-by-step explanation:
When a grinding stone wears down, it is important to adjust the tool rest to within a certain distance of an inch. Although the specific distance may vary depending on the recommendation of the manufacturer or the specific situation, a commonly recommended adjustment is within 1/16 of an inch. This ensures that the tool rest provides proper support and safety while using the grinding stone.