The best method for ordering additional or replacement rollers is to always specify the between frames dimensions (BF). This will ensure a proper fit for rollers and conveyor frames. If the end-user does not know what the BF dimension is, simply have this person measure between the frames of the specified unit. However, there are times when getting a between frames dimension is difficult. In this instance, it is very important to use the proper terminology to select a roller size. The only dimension acceptable in determining roller length when the BF is not known, is the “end of bearing” measurement. The importance here cannot be overstated. Since conveyor/roller manufacturers vary the length of the roller tube in relation to the manner in which the bearing is inserted and depending on the individual bearing being used-countless dimensions are possible. For example, one manufacturer may use an 18 1/2″ long tube in production of its 19″ BF roller. Another may be using a different bearing or possibly a different method of installing the bearing and cut its tube to a length of 18 1/4″. This 1/4″ difference is enough — believe it or not — to be the culrpit of serious problems.