Final answer:
The recommended gap between the top guard and the wheel on a bench grinder can vary, but older recommendations suggest a gap of 5 times the diameter side-to-side and 7-8 times the diameter deep. Newer recommendations suggest a gap of up to 8 diameters side-to-side and 15 diameters deep.
Step-by-step explanation:
The gap between the top guard and the wheel on a bench grinder can vary depending on different recommendations. An older rule of thumb suggests a gap of 5 times the diameter of the wheel side-to-side, and 7-8 times the diameter deep. However, newer work suggests a larger gap of up to 8 diameters side-to-side and 15 diameters deep.