Josh Cosford

By Josh Cosford, Contributing Editor Hydraulic oil contamination may cause significant damage to hydraulic systems and components, leading to reduced performance and productivity and increased maintenance and repair costs. Therefore, it’s crucial that you identify the symptoms of hydraulic oil contamination to prevent further damage and ensure optimal hydraulic system operation. Regular readers know how […]

By Josh Cosford, Contributing Editor Hose fittings (also called hose ends) are crimped or threaded onto either end of a hydraulic hose assembly and provide the technician with an interface to connect the system’s conduits. Hose end fittings come in two primary styles; field-serviceable screw-on and permanent crimped-on. This article discusses when you should use […]

Learn how three manifold designs — the common hydraulic integrated circuit, stackable bar designs, and simple passageways for pressure or return — are manufactured for hydraulic designs. By Josh Cosford, Contributing Editor When discussing manifolds, your mind will go to one of two places — bar manifolds with sandwich valves mounted atop or integrated circuits with a…

High pressure defines hydraulics, and the linear actuator we call the cylinder is the pièce de résistance of our industry. Other methods of creating rotational force may closely mirror the performance of a hydraulic motor. Still, a hydraulic cylinder has no peer for linear force (I’m looking at you, electric linear actuator). The force advantage…

By Josh Cosford, Contributing Editor We live in a global village where local preferences seem to matter less, and acceptance of unfamiliar ideas more widespread than ever. Thirty years ago, the idea of metric bolts, nuts, threads or other objects measured in round numbers was cringe-worthy, especially in the manufacturing space. Many found it annoying […]

By Josh Cosford, Contributing Editor Hydraulic quick couplings provide users with the ability to rapidly connect and disconnect hydraulic hoses to machines or other sections of plumbing. Also called quick-connects or quick disconnects, these fittings allow fluid to flow when the male and female sides are locked together. Conversely, when disconnected, the quick couplings prevent […]

When your customer’s cylinder arrives on your dock for repair, how often do you consider raw material when you quote the overhaul? Probably very little. Most hydraulic cylinders are manufactured from a combination of 1018/1020 cold rolled steel for the “square” components such as flanges, heads and caps. Piston rods mostly likely adhere to 1045 […]

By Josh Cosford, Contributing Editor Manufacturers make cellulose fibers from long chains of plant material processed into a pulp and then drawn out into strands. Glass media comes from a more complicated process of first drawing molten silica fibers and then combining them into a strand using a resin binder. The product of either process […]

Hydraulic reservoir design is critical in power unit performance, so selecting the right style elements will ensure efficient circuit design. If you have a hydraulic system, you have a reservoir. Full stop. Even “reservoir-less” systems still require an expansion tank to hold excess fluid. Aside from such unconventional designs, hydraulic reservoirs offer benefits above and…

Logic elements are fantastic little creatures. Sometimes call DIN valves or slip-in cartridge valves, they are the most basic valve design capable of controlling direction, flow and pressure. Their simple poppet construction nearly guarantees reliability while flowing upwards of a thousand gallons per minute or more. Unlike most of the Symbology series, this one requires…

Rotary actuators, in many cases, are a hybrid of linear and rotary actuators. Of course, in the fluid power realm, linear and rotary actuators are more affectionately referred to simply as cylinders and motors, respectively. A cylinder creates linear force when pressure acts up its piston’s surface area, while a motor creates rotational force when […]

In many ways, Industry 4.0 has yet to achieve widespread proliferation throughout fluid power machinery as it seemed we were promised. Baby Boomers are still waiting for their flying cars as promised by the Jetsons. It’s been nearly sixty years since the Jetsons got our hopes up, so I hope it doesn’t take so many […]

By Josh Cosford, Contributing Editor When well cared for, hydraulic cylinders should last decades. So long as they were designed for their application — meaning they perform within the bounds of their environment — there should be no reason for damage or wear outside of regular use. The mount, rod and raw material should have […]

Urethane (or polyurethane) seals are among the most versatile and durable materials used in fluid power sealing. Urethanes are cast into billets or molds to create the seals used in many of the hydraulic components you see every day, such as pump shaft seals, cylinder pistons and rod seals. The material benefits from countless possible […]

By Josh Cosford, Contributing Editor Thermoplastics are polymers with a unique capacity to become soft, pliable and moldable when heated while solidifying upon cooling. The moldability range lies between its glass transition temperature* and its melting point, so it’s essential to avoid overheating the material. Popular techniques such as injection molding and extrusion produce many […]

Heat exchangers help remove heat from hydraulic power units, helping to maintain fluid viscosity and reduce wasted energy. For all its myriad benefits, hydraulics still has a fundamental downside — heat. Adhering to the Laws of Thermodynamics, we must accept that any energy conversion results in increased entropy. In other words, converting mechanical energy from…

Vane pumps are quiet, efficient and reliable, especially when they’re provided care. However, they’re not indestructible and experience problems like every other pump. Just like all hydraulic pumps, when taken care of, they may last you a lifetime. Part of improving your vane pump’s life span is understanding what can go wrong through intelligent troubleshooting.…

By Josh Cosford, Contributing Editor It would help if you never underestimate the importance of your cylinder rod. The rod is not just the object transmitting the force from the cylinder’s piston but also the interface between that cylinder and your machine. Before you can correctly select and then design the piston rod, you must […]

By Josh Cosford, Contributing Editor An O-ring is a polymer seal most often used in fluid power as either a dynamic or static seal. For light-duty pneumatic applications, an O-ring is a suitable seal technology used in pistons, piston rods, valve spools and other locations in air systems. O-rings best suit the sealing of static […]

Most hydraulic fluid is oil-based, so we cannot forget the adage that oil and water do not mix well. However, when it comes to the hydraulic oil transferring energy around your hydraulic system, much more is at stake. Whether free or in saturation, the potential harm from water is more detrimental than merely pooling at […]

Skiving is removing the outer cover at the end of a hydraulic hose in the location of the crimp fitting. For some high-pressure applications, the hose’s inner tube ID may be skived to allow the hosetail to better fit. Using a specialized machine with externally rotating mandrels, the tooling cuts and then peels the outer […]

By Josh Cosford, Contributing Editor Physical laws, unlike governmental laws, are perfect. The heavy hand of the (physical) law keeps our fluid power realm in check, dictating liquids and gases’ behaviours at every location. I’d like to say very few alternate engineering fields so heavily rely on these laws and principles as fluid power, but […]

I once had a customer call to request I visit them at their own customer’s site to help with a “breakdown.” I’m always down to help a customer, so I gladly paid a visit. Arriving on-site, many looming pieces of machinery greeted me in a heavy equipment yard. An excavator sat atop a float trailer […]

Condition monitoring symbols are the lesser-known and lesser-used of the hydraulic library. It’s not that the components or the symbols representing them do not serve a useful purpose. It’s that the order of operations for designing and drawing a hydraulic system are actuators, pump(s), control valves and then conditioning components. Monitoring symbols represent the nice…

Eliminating downtime and ensuring safety in mining — two benefits hydraulics provides consistently. By Josh Cosford, Contributing Editor More than almost any other industry appropriating fluid power, mining is where safety sits front and center from design to execution. Surface mining enjoys bragging rights to some of the most massive machines ever manufactured by humans. […]