Honing

We can hone from a 1.25” to 22” inside diameter up to a length of 30’.

Yes, we recommend honing the barrel on most cylinder repairs. It removes light scratches and ovality to ensure optimal seal performance. Honing can also fix deeper scratches but doing so may require additional work or replacement of the piston and gland if the clearance becomes too great.

Absolutely. We’d be happy to help. Get in touch….

Hard Chrome Plating

Hard chrome plating is a form of electroplating. It is popular for its use as a surface coating due to its hardness, ability to minimize sliding wear, corrosion protection and for extending the life of metal parts.

Electro-deposited chrome is extremely hard, typically 66-70 on the Rockwell “C” scale which is used to determine the indentation hardness of a material. In comparison, hardened knife steels typically measure 58-62 HRC.

Hard chrome has excellent corrosion resistance but it plates in a micro-crack structure so it will rust over extended periods of time in wet environments.

No. Although the processes are similar, they serve different functions. Hard chrome is widely used in industrial applications for increased wear and corrosion resistance, reduced friction, and lubricant retention. Decorative chrome is a much thinner layer of chromium used mainly for aesthetic appeal.

No, as the metal has been ionically dissolved in the electrochemical bath.

No, we are not set up for automotive parts, but there are many places around that can help.

Any ferrous and most non-ferrous metals can be chrome plated. The most common materials are steel, cast iron, stainless steel, bronze, brass, and copper. Metals like magnesium and titanium require an underlay of zinc, copper, or nickel. Aluminum typically requires a copper or nickel undercoat.

The life span of hard chrome plating depends on the working environment and how thick the chrome is applied.

Hard chrome can be applied anywhere from 0.0005” – 0.025” (0.013mm – 0.635mm). The max chrome thickness is generally dictated by clearance to mating parts.

A piece can be hard chrome plated many times as long as the base metal remains in good condition.

Leveling

Hydraulic leveling cylinders are used to stabilize a working platform. Also known as outriggers, stabilizers, leveling jacks and landing gear, they provide a stable base by distributing the load over a wider base.

A mechanical locking leveling cylinder can achieve a compressive load strength 3-5 times the lifting capacity with zero deflection. A hydraulic locking leveling cylinder provides ease of use and reduced setup and tear down time.

Both styles of nut offer the ability to mechanically lock a cylinder at a specific extension. A standard nut is a solid, single piece machined from high tensile strength material. A split nut is very similar but split down the centre and hinged allowing for faster setup and tear down.

Custom Machine

The cost varies and is dependent on size, materials, complexity, and order quantity.

Lead time depends on several factors such as material availability, cylinder complexity, order quantity, special items, and our current workload. Contact us for more information.

Yes. In fact, it is common for us to manufacture a single prototype for a customer in the research and development phase of a project.

Yes. We can reverse engineer a design and make modifications and recommend improvements along the way. This is common when the original manufacturer is no longer in business or when drawings are simply not available.

Yes. We prefer to manufacture using our own design, but we can manufacture cylinders based on external drawings.

Position

A “SMART” cylinder is a type of hydraulic or pneumatic actuator that incorporates a linear transducer (sensor) that can be mounted internally or externally. The sensor provides instantaneous feedback of position and velocity and can be outputted to various analog and digital formats.

Through electro-hydraulic control, various equipment functions can be automated to improve overall performance and efficiency while reducing maintenance and downtime. Other benefits include repeatability, lockout and safety, dynamic self-adjustment, and remote adjustability.

Yes, an external sensor can be added to most existing cylinders while an internal sensor can be installed if there is ample room for the sensor head in the endcap

Telescopic

A telescopic cylinder features an outer barrel and 2-6 nested stages (sometimes called sleeves) that decrease in diameter and fit inside each other. As hydraulic pressure is applied, the largest sleeve extends until fully extended. Then the process repeats until the final sleeve (also known as the rod or plunger) is extended, resulting in the total cylinder extension.

Telescopic cylinders, also known as multi-stage cylinders, can achieve a longer stroke than a single-stage cylinder, while maintaining a short retracted length. It is helpful in space-constrained environments such as the dump body of a dump truck. Think of a telescope, where the telescopic cylinder got its name.

A single acting telescopic cylinder uses hydraulic pressure to extend an external force, such as gravity to retract. A double acting telescopic cylinder uses hydraulic pressure to both extend and retract. A single/double acting combination cylinder uses hydraulic pressure to retract only a portion of the stroke, maintaining design simplicity and reducing overall cost.

Welded Design

Both welded and tie-rod cylinders are common cylinder types, and they differ in endcap design. Welded cylinders feature an endcap welded to the barrel, while the endcap of a tie-rod cylinder is held on with tie-rods that run the length of the cylinder. Although a tie-rod cylinder can be easier to service, a welded cylinder generally takes up less space, can handle higher operating pressures and withstand harsher environments.

Absolutely. A welded cylinder typically features a welded endcap and a threaded or bolted gland, allowing for ease of disassembly and service. Occasionally we come across cylinders

that are welded on both ends, and the cylinder is rebuildable, but must be machined apart to be rebuilt.

The most common causes of welded cylinder failure are:

  • Fluid Contamination: Foreign particles in the hydraulic fluid can scratch the cylinder bore and cause corrosion.
  • Side Loading: When an external force is applied perpendicular to the cylinder, it creates wear. Excessive side loading can cause a bent or broken rod.
  • Rough or Scored Rod: A scored rod will damage the seals, causing difficulty to maintain pressure, reduce life, and require frequent replacement.
  • Over-Pressurizing: Repeatedly handling more pressure than it is designed for causes snap rings to dislodge and becomes dangerous to operate.

Service FAQ

We repair all kinds of cylinders. From small pin-lock cylinders to 40’ long multi-stage cylinders, we repair and service them all.

This depends on the extent of the repairs, parts and material availability, and our current workload. Ask our inside sales team about options to expedite delivery.

Yes, we can. We prefer to perform at least a basic inspection on the components, but with time or budget constraints, we can simply reseal a cylinder.

The most common causes of hydraulic cylinder failure are:

  • Fluid Contamination - Foreign particles in the hydraulic fluid can scratch the cylinder bore and cause corrosion.
  • Seal Failure – Seals can be damaged by excessive heat, improper installation, pressure spikes and contamination.
  • Mount Connection Failure – When a cylinder is overloaded or misaligned, excessive stress causes faster wear on the mount connections.
  • Side Loading - When an external force is applied perpendicular to the cylinder, it creates wear. Excessive side loading can cause a bent or broken rod.
  • Rough or Scored Rod - A scored rod will damage the seals, causing difficulty to maintain pressure, reduce life, and require frequent replacement.
  • Over-Pressurizing - Repeatedly handling more pressure than it is designed for causes snap rings to dislodge making the cylinder dangerous to operate.

Yes, we can straighten most cylinder rods and stages. However, we occasionally encounter rods with a diameter, length, or material that is unfeasible for straightening.

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Since 1990, RHK has been manufacturing hydraulic cylinders for a wide range of industries. Our Sales and Engineering team has extensive experience and is standing by to develop a custom solution for your application.

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