The general concept of manual lubrication is that "if a little is good, more must be better". This cannot be further from the truth. Using too much lubricant is a waste. Overfilling any bearing can cause the seals to push out, allowing dirt, debris or water to then enter the bearing, causing failures.
High speed bearings that support machinery such as saws require the right amount of lubrication in exact locations. Over lubricating the bearings can generate heat which decreases its life. Having to replace short-lived bearings can cause unscheduled downtime and impact budgets.
On average typical nylon kiln cart bushings require replacement every 2-3 months. Due to the high continuous working temperatures of a maximum 110-130ºC and high loads the nylon extrudes from the bushing, reducing the life due to oxidation of the plastic and poor lubrication.