Grease gun calibration, sampling, change-over and storage
The routine procedures that decide whether the grease you bought does its job: measuring gun output, taking a grease sample, switching products and storing them.
Measure what the gun delivers
Most grease guns do not deliver the same amount each stroke. Pump ten strokes onto a scale, divide by ten and note the average; convert to volume by dividing by the grease density. Keep the figure at the grease point.
Filling a bearing
Use clean fresh grease in a clean dry area. A syringe measures small quantities accurately. For a free bearing, divide the fill by the number of rolling elements and place it between them, then turn the bearing without load. For a bearing in a housing, add grease slowly through the fitting while the bearing turns without load.
Taking a grease sample
Use clean crush-proof glass or plastic bottles, wear gloves and clean the point first. Relubricate a little while running so fresh grease displaces used grease, then stop the machine safely. Remove the outer contaminated layer and take the sample closest to the rolling elements and cage with a clean spatula, or draw it through clean plastic tube with a syringe when it is not reachable. Label with date, equipment, run time of the grease and the baseline grease name.
Changing from one grease to another
- Check the bearing arrangement lets excess grease escape.
- Check that the old and new greases are compatible.
- Check the bearing is healthy first; lubricant cannot repair bad fits or damage.
- With the bearing turning, pump in the new grease slowly until the grease coming out looks like the new product.
- Repeat after one to two hours, run for a week, relubricate normally and relubricate more often for the first two intervals.
- Track power, current and temperature through the change.
Storage and shelf life
Keep grease in the original container in a clean, cool, dry place, and buy close to the amount needed. Shelf life depends on the product and storage. Pre-lubricated bearings have the same shelf life as the grease; if stored longer, turn them unloaded from time to time.
- Clean fittings before every lubrication.
- Pump slowly.
- Apply new grease to a bearing that is turning.