Before everything had to be computer-driven and laser guided, oil cans had a semi-flat bottom that was slightly convex. To oil something, you turned it over, put the tip where you wanted the oil, and pressed on the bottom with your thumb, causing the bottom to go "doink" and squirt oil where you wanted it. When you released your thumb, the bottom would go "doink" back to shape.
Where the metal panel will pop in and out causing an oil can effect. It is caused by stretched metal from improper sheet metal work.
Usually cured by my friend the torch or heat wrench.
Last edited by Hankdogg; 02/26/2010 9:15 PM.
