“How do you know when you have added enough grease?”
While there is no easy answer to the question of manual grease relubrication cycles and volumes, it does not have to be a mystery. The best policy, of course, is to measure the size of the bearing shaft, width and bearing outer diameter, as well as the grease gun output per stroke, then calculate the amount required.
This SKF formula is easy to use:
Gq = 0.114 DB
Where: Gq = Grease quantity in ounces
D = Bearing outside diameter in inches
B = Total bearing width in inches
If a simple formula is not available, estimate the number of shots based on the shaft diameter for bore diameters up to 6 inches. For example, estimate the number of inches in the shaft. Multiply that number by itself to get a rough estimate of the number of shots from the grease gun. Apply the last half of these shots slowly, and at the point that you begin to experience resistance, stop pumping. This rule of thumb does not hold for bearings with bore diameters of greater than 6 inches.