In rod end applications with either male or female threaded shanks, it is advisable to use hexagonal nuts as jam-nuts to ensure a tight fit and prevent the nut from working loose. Technically speaking the problem is negligible however product availability might cause some holdups; rod ends with special threads (left-hand, fine thread pitch for pneumatics or inch UNF threads) require special jam-nuts and users often find that limited quantities of suitable nuts are not easily available on the market. The Getecno range includes a series of jam-nuts for special purposes which might otherwise be difficult to procure.

There are three categories of jam-nuts for special purposes: