Torque Definitions

R.S.M.El. — American Society of Mechanical Engineers, known for setting codes and standards for mechanical

devices, including torque.

CW — Clockwise. Used in all accuracy statements & Certs. Some tools have different accuracy depending on direction of use.

CCW— Counter Clockwise

Calibration - Adjusting a torque tool or a torque transducer to bring it back within spec, which is performed on a

calibration system such as the CDI 2800-1 or 2000-1. Typical calibration accuracy is t 4% CW of indicated

value.

Certifications — Also called a "Cert", this is a form which lists the results of the calibration test. Almost all CDI tools are supplied with a N.I.S.T. traceable cert. CDI also conforms to the ISO 6789, which is the standard set forth by the International Organization for standardization (ISO) for torque measurement.

Cycling — For mechanical torque wrenches, to "exercise" the wrench for use. With a new wrench, and for first use of the day, set the wrench at the desired torque value and pull for several clicks on a stationary fastener. This exercises the internal wrench mechanism and ensures smooth and accurate operation.

ISO 17025 — A laboratory accreditation standard. Most all torque wrenches (including CDI)

do not come with ISO 17025 accredited certifications. But torque wrenches can receive accredited certification for an additional fee (range of $100-400 depending on tool) if the end-user desires.

N.I.S.T — National Institute of Standards and Technology is a non-regulatory agency of the US

Department of Commerce. They are the federal agency that sets standards for all weights and measures in the U.S. AIl CDI torque products are calibrated on testers calibrated with weights and arms that are all traceable back to N.I.S.T.

Newton — A Newton is a common unit of weight used for torque from the SI system (not metric). Equivalent to 102 grams / .273 pounds.

Rolling Torque — Measuring the prevailing torque, or resistance, of a rotating shaft.

Strain Gage — A strain gage is an electronic device used to measure the bend or turn resistance of an

object. The measured strain is then translated into torque.

Testing — To determine the accuracy of the tool. It does not include adjusting the tool. Commonly called “as found" data.

Torque Plus Angle {T & A)— Tightening the fastener to a specific torque, then further turning a specific number of degrees (angle) of rotation. Example: 70 ft. lbs. + 40 degrees.

Torque to Yield(TTY)- Same method as torque plus angle except utilizes “single use" or "TTY" fasteners. These are special one-time-use fasteners which are stretched into their yield Zone and cannot be used again.