What Is the Dash on a Hydraulic Fitting?

••• K-Paul/iStock/GettyImages

In hydraulic systems, the dash number, dash size or simply dash is an industry standard measuring system for hoses and fittings. If you are replacing hoses or fittings, you should choose the correct dash size to avoid damage from heat or turbulence.


The size of a hydraulic hose is described by its internal diameter, expressed as a dash number. The internal diameter of a hose measuring 1/4 of an inch can be divided into four segments, each measuring 1/16 of an inch, so the hose has a dash number of 4.


Dash is used, along with other configuration codes, to provide meaningful shorthand descriptions of hydraulic parts. The dash is a single number that precedes the coupling description of a hydraulic part and denotes the fitting size in sixteenths of an inch.


If a hydraulic adapter part is described as 6 MP – 4 FPX 90, the numbers 6 and 4 are dash numbers; this part has a 6/16 (3/8) of an inch male connector on one end and a 4/16 (1/4) female swivel connector on the other, at right angles (90 degrees) to each other.

Related Articles

How to Find Bearing Numbers by Size
How to Calculate KVA to MVA
How Hydraulic Pilot Valves Work
How to Calculate Hydraulic Press Force in Tons
What are Gehl 4625 Skid Steer Specifications?
The Dimensions of a NEMA 56C
How to Calculate CFM Output
What Is an Instrument Which Measures the Pressure of...
What Is a Hydraulic Power Pack?
What Is a Centrifugal Blower?
How to Find Bearing Numbers by Size
What Is a Hi-Shear Fastener?
How to Read an IC Part Number
How to Install a Flow Control Valve
Mustang Skid Loader Specifications
How do I Calculate the Geometric Mean on an HP 12C?
How Does a Hydraulic Dump Truck Work?
How Do Mechanics Use Math?
What Is a Ferrite Clamp?

Dont Go!

We Have More Great Sciencing Articles!