Checkline AWS RDF [RDFAHE-2500] 2500 Lb-ft / 3390 Nm Washer Encapsulated Rundown Fixture, 1.5" Male Sq Drive, Specify Female Sq, 3/4, 1 or 1.5". AWS RDF Rundown Fixture - Joint Simulators for Torque Testers. Required for accurate torque measurement for power-driven torque controlled tools (electric, hydraulic or pneumatic). AWS RDF Joint Simulators (also referred to as Rundown Fixtures or Adapters) are required for accurate torque measurement for power-driven torque controlled tools (electric, hydraulic or pneumatic). They are not necessary or useful when measuring torque on manually-operated torque tools (screw-drivers, wrenches, etc.). The AWS RDF simulate the conditions found when using the tool in real-world conditions, allowing the speed of the power tool motor to ramp-up to normal operating speeds resulting in a more accurate and repeatable measurement of the torque. The AWS RDF are typically fabricated from machined steel with the appropriate drive size as needed. Internally it is comprised of a series of Belleville washers, designed to compress as the bolt tightens. By varying the arrangement of these washers, various joint rates can be simulated soft, medium and hard. Unless otherwise, specified, Joint Simulators are configured to simulate a medium joint. The joint rates can be adjusted by the user by changing the orientation of the Belleville washers upside down. Special Run-Downs: HD Encapsulated Model: The HE series rundown fixture is comprised of a shroud, threaded body, bolt and encapsulated washers. B Encapsulated Model: The B series rundown fixture is comprised of a shroud, encapsulated threaded body, bolt, nut and washers. All components are contained. Please contact us for more info on our custom run-downs.