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Revision A
Term
Definition
RoHS (Reduction of
Hazardous Substances)
A directive by the European Union to restrict use of certain hazardous substances (such as
hexavalent chromium used in some yellow zinc platings)
rpm
Revolutions per minute
SAE
Society of Automotive Engineers
Screw
A headed and externally threaded fastener that threads into preformed threads or forms
its own thread into a mating part
SDD
Single-draper drive
SK
Single knife
Soft joint
A joint made with use of a fastener where joining materials are compressible or
experience relaxation over a period of time
spm
Strokes per minute
SR
Single reel
Tension
Axial load placed on a bolt or screw, usually measured in Newtons (N) or pounds (lb.)
TFFT
Turns from finger tight
Timed knife drive
Synchronized motion applied at cutterbar to two separately driven knives from a single
hydraulic motor
Torque
The product of a force X lever arm length, usually measured in Newton-meters (Nm) or
foot-pounds (lbf
∙
ft)
Torque angle
A tightening procedure where fitting is assembled to a precondition (finger tight) and then
nut is turned farther a number of degrees to achieve its final position
Torque-tension
The relationship between assembly torque applied to a piece of hardware and axial load it
induces in bolt or screw
Truck
A four-wheel highway/road vehicle weighing no less than 3400 kg (7500 lb.)
UCA
Upper cross auger
Untimed knife drive
Unsynchronized motion applied at cutterbar to two separately driven knives from a single
hydraulic motor or two hydraulic motors
Washer
A thin cylinder with a hole or slot located in the center that is to be used as a spacer, load
distribution element, or locking mechanism