[Al Skierkiewicz]

Everyone,
The terminals tend to work loose with time because the terminal on the battery and the cable terminal wear against each other and the hardware. This is not the only effect as constant tightening of the hardware cause the terminals to deform making the conditions worse.
Tom (above) uses the same solution we have been using for years. A star washer between the terminals and a star washer under the nut are sufficient to keep everything locked together for the life of the battery. Many will ask about the star washer adding some resistance and this is true. However, the bite of the washer overcomes any surface scum on either of the terminals and when tight produces at least the same surface area of contact that the hardware and terminals produce when new. We also bend over the cable terminal so it lies close to the battery top or side (depending on use) and then cover the entire connection with 3/4" heatshrink. This method is easy for students to assemble as it does not need any great strength when tightening the hardware. It is also very inexpensive as #10 star washers can be purchased in quantity at any hardware store for a couple of bucks. You can substitute a keps nut if you have them on hand.