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Revision A
Term
Definition
NPT
National Pipe Thread: A style of fitting used for low-pressure port openings. Threads on
NPT fittings are uniquely tapered for an interference fit
Nut
An internally threaded fastener designed to be paired with a bolt
ORB
O-ring boss: A style of fitting commonly used in port openings on manifolds, pumps,
and motors
ORFS
O-ring face seal: A style of fitting commonly used for connecting hoses and tubes. This
style of fitting is also commonly called ORS, which stands for O-Ring Seal
PARK
The slot opposite the NEUTRAL position on operator
’
s console of M1 Series windrowers
R1 SP Series
MacDon R113 and R116 Rotary Disc Headers for windrowers
R2 SP Series
MacDon R216 Rotary Disc Headers for windrowers
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
SCR
Selective catalytic reduction
Screw
A headed and externally threaded fastener that threads into preformed threads or forms
its own thread when inserted into a mating part
SK
Single knife
SKD
Single-knife drive
Soft joint
A flexible joint made by use of a fastener in which the joining materials compress or relax
over a period of time
spm
Strokes per minute
Tension
An axial load placed on a bolt or screw, usually measured in Newtons (N) or pounds (lb.).
This term can also be used to describe the force a belt exerts on a pulley or sprocket
TFFT
Turns from finger tight
Torque
The product of a force * the length of a lever arm, usually measured in Newton-meters
(Nm) or foot-pounds (lbf
∙
ft)
Torque angle
A tightening procedure in which a fitting is assembled to a specified tightness (usually
finger tight) and then the nut is turned farther by a specified number of degrees until it
achieves its final position
Torque-tension
The relationship between the assembly torque applied to a piece of hardware and the
axial load it induces in a bolt or screw
ULSD
Ultra-low sulphur diesel
Washer
A thin cylinder with a hole or a slot located in the center, used as a spacer, a load
distribution element, or a locking mechanism
Windrower
The power unit for a header
WOT
Wide-open throttle