56XX Series and 54X Series Tractors are mechanical devices which are installed, (in matching pairs, left hand and complimentary right hand), into printers for the function of accurately moving continuous forms. The model Series 56XX and 54X tractors have 6 and 4 pins respectively engaged in the form's vertical edges to feed form at a rate of 2.5 inches (63.5mm) per revolution of the drive pulley. Models meet these basic specifications: Physical Dimension: See customer sales drawing for specifics. Effective Pin Height: Measured from base of the pin & upward from the belt. It is the height at which pin diameter remains constant. See 56XX/54X Belt Specification 301058. Lid Force: 1lb. (0.45 kgf) Minimum required to exceed lid gap will exist over 25k operations on the 56XX and 12k operations on the 54X.* Pin Alignment: 0.007 (0.177mm) over 5 pins with a minimum of 0.5lb (0.22 kgf) tension on the belt. Drive Shaft: (Maximum Sizes to fit in tractors.)   1/4" Square = 0.251 (6.375mm)   6mm Square = 0.236 (6.001mm)   5/16" Square = 0.313 (8.001mm)   Spline: Chord = 0.099 (2.515mm)              16 Tooth Outside Diameter = 0.379 (9.627mm)              Root Diameter = 0.311 (7.900mm)              Fillet Radius = 0.005 (0.127mm)              Corner Radius = 0.007 (0.178mm) Minimum Stabalizer Shaft:   5/16" (8mm) Round = 0.309/0.317 (7.85/8.05mm)   0.500 (12.7mm) Round = 0.499/0.501 (12.67/12.72mm) Clamp Force: 3.0lbs (1.33 kgf) Minimum in locked position required with standard handles. (Note: due to excessive operating force required to meet this specification on "thin" or "short" handles will meet this force only above 0.311 (7.90mm) diameter. Handle Locking/Unlocking Force: 4.0lbs (1.8 kgf) maximum on a 0.311 (7.90mm) dia. shaft. Clamp Life: All handles are designed and tested to meet 25k operations without functional failure. Form Specification: Tractors have been tested to perform with paper that conforms to ISO 2784-1974 (E). Product Life: Customer must determine product life based on actual in-house testing. PHD offers a wide variety of bearings to meet bearing life requirements. Belt replacement kits may extend the life of the product and reduce MTTR.** Operating Ambient: 4° C to 40° C. 15-95 % RH non-condensing. Storage Ambient: -40° C to 71° C. 5-95 % RH non-condensing. *Contact PHD Engineering for extended lid life spring to make 54X lid meet 25k openings. **Contact PHD Engineering to get more details on bearing ratings.