Parker Hydraulic Cylinders: Complete Guide to Series, Specs, Parts & Alternatives
Expert hydraulic cylinder guide from HydraulicCylinders.com
Parker Hydraulic Cylinders: Complete Guide to Series, Specs, Parts & Alternatives
Parker Hannifin is the largest motion and control technology company in the world, and their hydraulic cylinder division reflects that scale: dozens of series, thousands of SKUs, and a global distribution network that can put parts on a loading dock in 24–48 hours. For maintenance engineers and procurement teams, that breadth is both an asset and a source of confusion.
This guide cuts through the catalog. We cover Parker’s primary hydraulic cylinder series — HMI, MH, and 2H — explain where each is specified and why, walk through the distributor and repair parts ecosystem, and give you a straight assessment of when Parker is the right call and when alternatives should be on the table.
Parker Hannifin: Company and Division Overview
Parker Hannifin Corporation (NYSE: PH) is headquartered in Cleveland, Ohio. Their Cylinder Division — part of the broader Industrial and Mobile Systems group — produces hydraulic, pneumatic, and rodless cylinders for industrial machinery, mobile equipment, process industries, and specialty applications.
Parker cylinders are manufactured at multiple North American and international facilities, with the primary hydraulic cylinder production at their Ogden, Utah and Jacksonville, Alabama plants. The Cylinder Division’s catalog includes:
- Industrial tie-rod cylinders (2H, 3H, 6H, 10H series)
- Mill-duty cylinders (MH, MHS, MHD series)
- Low-profile / compact cylinders (HMI, HL, LP series)
- Custom / engineered cylinders (PH series and application-specific)
- Mobile cylinders (M series — front fork lift, mobile equipment)
The series that appear most frequently in industrial facilities and mobile equipment fleets are the 2H, MH, and HMI. Understanding these three covers the majority of Parker cylinder installations.
Parker 2H Series: The Workhorse Tie-Rod Cylinder
What It Is
The Parker 2H is a NFPA-standard tie-rod hydraulic cylinder — the most widely used industrial hydraulic cylinder design in North America. NFPA (National Fluid Power Association) standardization means the 2H’s mounting dimensions, port locations, and stroke specifications are interchangeable with cylinders from other manufacturers that follow the same standard.
This interchangeability is significant for maintenance engineers: a Parker 2H at a given bore and stroke can be replaced with an equivalent Bosch Rexroth, Eaton, or Prince cylinder without modifying plumbing or mounting.
2H Specifications
| Parameter | Specification |
|---|---|
| Bore sizes | 1.5, 2.0, 2.5, 3.25, 4.0, 5.0, 6.0, 7.0, 8.0 in |
| Standard strokes | 1 in to 120 in (custom longer on request) |
| Maximum pressure | 3,000 PSI |
| Seals (standard) | Buna-N (NBR); Viton available |
| Rod material | Chrome-plated carbon steel standard; stainless available |
| End caps | Aluminum (standard); steel (optional for pressure applications) |
| Mounting styles | All NFPA styles: cap end clevis, flange, trunnion, side lug, cap square |
| Fluid compatibility | Mineral oil, water-glycol, phosphate ester (with Viton seals) |
| Temperature range | -40°F to +250°F (standard seals) |
Where 2H Cylinders Are Specified
The Parker 2H is the default specification for:
- General industrial automation (clamping, pressing, feeding, indexing)
- Machine tool and fixture applications
- Material handling: conveyors, lifts, tilting tables
- Packaging and food processing equipment
- Press brakes and metal forming machines
- Plastics injection molding machines
The 2H’s NFPA compliance and broad availability through Parker’s distributor network make it the path of least resistance for most industrial hydraulic applications operating under 3,000 PSI.
2H Strengths and Limitations
Strengths:
- NFPA standardization — broad cross-reference and replacement options
- Extensive distributor stock — often available same-day at Parker stores
- Comprehensive seal kit availability
- Wide bore range covers most industrial applications
- Cost-competitive against comparable NFPA cylinders
Limitations:
- 3,000 PSI maximum — not suitable for high-pressure industrial applications
- Tie-rod construction has lower lateral load tolerance than mill-duty cylinders
- Not designed for continuous-duty shock loading
- Standard aluminum end caps reduce suitability for severe-duty environments
Parker MH Series: Mill-Duty Construction for Severe Applications
What It Is
The Parker MH (Mill Hydraulic) series is a heavy-duty cylinder designed for the punishment of steel mills, press operations, die casting, and other severe-duty industrial environments. Where a 2H has aluminum end caps, the MH uses heavy steel. Where a 2H is rated to 3,000 PSI, the MH is built for 2,000–3,000 PSI continuous duty with shock loads that would destroy a tie-rod cylinder.
The MH is a welded or flanged construction — no tie rods. The barrel is welded or bolted directly to heavy steel end caps, creating a rigid, monolithic cylinder body that handles side loading, shock, and vibration far better than tie-rod designs.
MH Series Specifications
| Parameter | Specification |
|---|---|
| Bore sizes | 2.5 in to 24 in (larger bores on custom) |
| Maximum pressure | 3,000 PSI (standard); 5,000 PSI (heavy-wall option) |
| Rod diameter | Oversized relative to bore — selected for buckling resistance |
| End cap construction | Heavy steel, welded or bolted flange |
| Seals | Polyurethane standard (better wear than NBR for shock applications) |
| Chrome plating | Heavy chrome standard (0.003–0.005 in) |
| Mounting styles | Side lugs, flange, trunnion, front/rear clevis — all heavy-duty |
| Rod options | Single rod, double rod, hollow rod |
| Cushioning | Adjustable cushions standard on most configurations |
Where MH Cylinders Are Specified
The MH series is the standard specification for:
- Steel mills and metal processing: Roller gap control, coiler arms, banding press, crop shear
- Die casting machines: Injection press, die clamping, ejector circuits
- Hydraulic presses: Stamping, forming, punching, clinching
- Foundry equipment: Squeeze-out rams, core ejectors, flask handling
- Rubber and plastics presses: Vulcanizing, compression molding
- Heavy material handling: Dock levelers, rail car positioners
The MH’s welded construction and polyurethane seals are purpose-built for the shock loading and contamination exposure that characterizes steel mill and press environments. Tie-rod cylinders simply don’t survive here.
MH vs. 2H: When to Specify Which
| Factor | 2H Tie-Rod | MH Mill-Duty |
|---|---|---|
| Pressure | Up to 3,000 PSI | Up to 3,000–5,000 PSI |
| Shock loading | Not recommended | Designed for |
| Side loading | Minimal tolerance | Moderate tolerance |
| Environment | Clean to moderate | Severe: scale, heat, vibration |
| Cost | $ | $$-$$$ |
| Repairability | Easy — tie rods removable | Harder — requires hydraulic press |
| Lead time | Same-day to 2 days (distributor stock) | 1–6 weeks depending on bore |
| Standard for: | Automation, machine tools | Mills, presses, die casting |
Parker HMI Series: Compact, High-Pressure Performance
What It Is
The Parker HMI series bridges the gap between the 2H’s general-purpose design and the MH’s full mill-duty construction. It’s a mid-duty cylinder built for applications requiring more pressure capacity and ruggedness than the 2H can deliver, without stepping up to the full cost and weight of the MH.
The HMI features:
- Higher pressure rating: Up to 5,000 PSI working pressure
- Compact envelope: Shorter overall length relative to stroke versus the 2H
- Heavier rod: Larger rod-to-bore ratio than 2H for better buckling resistance
- Steel end construction: Not aluminum end caps — more durable in moderate-duty environments
HMI Series Specifications
| Parameter | Specification |
|---|---|
| Bore sizes | 2.0 in to 8.0 in |
| Maximum pressure | 5,000 PSI |
| Rod material | Chrome-plated steel, oversized relative to 2H equivalents |
| End caps | Steel (not aluminum) |
| Seals | Polyurethane standard |
| Cushioning | Adjustable cushions available |
| Mounting | NFPA-compatible mounting dimensions at standard pressure ratings |
Where HMI Cylinders Are Specified
The HMI is the preferred specification for:
- Mobile hydraulic equipment (loader arms, boom cylinders, stabilizer jacks) where space is constrained
- Industrial presses operating at 3,000–5,000 PSI where MH is over-specified
- Machine tools with moderate shock and tight envelope requirements
- Offshore and marine equipment requiring compact, high-pressure capability
- Test bench and laboratory hydraulics requiring high pressure in a standard mounting envelope
Key differentiator: The HMI’s 5,000 PSI rating is the deciding factor. If your system operates above 3,000 PSI — or if system relief valves are set anywhere near 3,000 PSI with potential for transient spikes above — the HMI is a safer specification than the 2H.
Parker Series Comparison at a Glance
| Series | Max Pressure | Best For | Cost Tier | Lead Time |
|---|---|---|---|---|
| 2H (tie-rod) | 3,000 PSI | General industrial automation, machine tools | $ | Same-day – 3 days |
| HMI | 5,000 PSI | Compact high-pressure, mobile equipment | $$ | 1–5 days |
| MH (mill-duty) | 3,000–5,000 PSI | Steel mills, presses, foundry, severe duty | $$$ | 1–6 weeks |
| 3H (large bore) | 3,000 PSI | Large-bore automation (8–24 in) | $$$+ | Custom lead |
| 6H (heavy-duty) | 3,000 PSI | Presses, heavy industrial | $$$ | 2–4 weeks |
| Custom (PH) | Application-specific | Non-standard stroke/bore/special materials | $$$$ | 4–16 weeks |
Where to Buy Parker Hydraulic Cylinders
Parker operates one of the largest industrial distributor networks in North America. Purchasing options fall into three categories:
Parker Authorized Distributors (Recommended)
Parker’s authorized distributor network — listed at parker.com/distributors — offers:
- Direct access to Parker’s catalog with verified pricing
- Stocking of common 2H and HMI cylinders in high-volume bore/stroke configurations
- Parker technical support access for specification questions
- OEM seal kits and replacement parts
- Warranty coverage on new cylinder purchases
To find a Parker distributor: Enter your zip code on Parker’s distributor locator. Request a distributor that explicitly stocks Cylinder Division products — not all Parker distributors carry cylinders (some specialize in hose/fittings or filtration).
Parker SSD (Single Source Distributor) Locations
Parker’s Parker Store locations are company-operated or affiliated stores offering walk-in service for hose assemblies and cylinder parts. These are particularly useful for same-day seal kit purchases on common 2H bore sizes.
Industrial Distributors (Cross-Listed Stock)
Large industrial distributors — Grainger, Applied Industrial Technologies, Motion Industries — carry Parker cylinders through their distribution channels. Pricing is typically 5–20% higher than buying direct from an authorized Parker cylinder distributor, but their broad inventory and billing account relationships make them convenient for facilities that consolidate purchasing.
For standard 2H cylinders in common bore/stroke: Grainger and Applied stock these and can ship same-day or next-day in most markets.
For MH or HMI cylinders: Go direct to an authorized Parker cylinder distributor. These series are less commonly stocked at general industrial distributors.
Parker Cylinder Repair Parts
OEM Seal Kits
Parker offers OEM seal kits for all current and many legacy cylinder series. To order the correct kit:
- Identify the series: 2H, MH, HMI, etc.
- Record the bore diameter: Stamped on the cylinder barrel nameplate
- Identify the seal material: Standard (Buna-N/NBR) or optional (Viton, polyurethane)
- Reference the Parker part number: Printed on the cylinder nameplate — format varies by series
Parker seal kits are available through authorized distributors and Parker Store locations. Most common 2H kits (2–4 inch bore) are stocked and available same-day.
Replacement Rods and End Caps
Parker offers replacement chrome rods for the 2H and HMI series — useful when a cylinder has a scored or pitted rod but the barrel and end caps are serviceable. Rod replacement is typically more economical than full cylinder replacement when:
- The barrel bore is within tolerance (verify with bore gauge)
- End caps are undamaged
- The chrome damage is isolated to the rod
Replacement rods are ordered by part number through authorized distributors. Lead time is typically 3–10 days for standard sizes.
Legacy and Discontinued Cylinders
Parker maintains seal kit availability for many discontinued cylinder series. For legacy cylinders where Parker kits are unavailable:
- Bring physical seal samples and groove dimensions to a hydraulic supply house
- Most standard Imperial-dimension seals are available from aftermarket suppliers (Hallite, Trelleborg, Parker’s own seal division)
- Some rebuilders specialize in legacy Parker cylinder kits — a distributor can refer you
For repair procedures and in-field service guidance, see our hydraulic cylinder repair guide.
Parker Alternatives: When to Consider Other Brands
Parker is the dominant brand, but it’s not always the best choice for every situation. Here’s an honest look at when alternatives deserve consideration.
Bosch Rexroth (CDL1 / CDT3 Series)
Consider when: You’re building an all-Rexroth system (pumps, valves, cylinders) and want single-vendor support. Rexroth’s CDL1 (NFPA tie-rod) is fully interchangeable with Parker 2H on mounting dimensions. European equipment specifications often default to Rexroth.
Rexroth’s edge: Superior integration with Rexroth proportional valve systems; European distributor network exceeds Parker in some markets.
Eaton Vickers (VH, MC Series)
Consider when: Your facility already has Eaton hydraulic power units and a strong Eaton service relationship. Eaton NFPA cylinders cross directly to Parker 2H.
Prince Manufacturing
Consider when: Budget is the primary driver for a standard NFPA tie-rod application. Prince cylinders are made in the USA (North Sioux City, South Dakota), priced 20–35% below Parker 2H, and fully NFPA-compatible. Quality is acceptable for lower-duty applications.
Not recommended for: Severe-duty, high-cycle, or applications where downtime cost exceeds part cost savings.
Custom Rebuild vs. New Parker
For large-bore MH cylinders (8 in bore and up), custom rebuild from a qualified cylinder shop is often more economical than new Parker supply, especially for non-standard stroke configurations where Parker lead times extend to 6–12 weeks. See our sizing guide for help specifying replacement cylinders.
Specifying Parker Cylinders: Common Mistakes
1. Over-specifying series for the application Specifying MH mill-duty cylinders in a clean industrial automation application is expensive and unnecessary. The 2H performs fine in controlled environments — save the MH spec for environments that actually demand it.
2. Under-specifying pressure rating Specifying a 2H in a system where transient pressure spikes regularly reach 2,800–3,000 PSI is risky. Pressure spikes in hydraulic systems routinely exceed nominal by 20–50%. If your system relief is set at 2,500 PSI, consider HMI for critical circuits.
3. Ignoring rod diameter on long-stroke applications Long strokes with undersized rods buckle. Parker’s 2H standard rod diameters are adequate for most applications within published stroke limits, but check the Parker Cylinder Selection Guide (available at parker.com) for maximum stroke recommendations at each bore and rod diameter combination.
4. Ordering by stock number without confirming current revision Parker cylinder series go through design revisions. Always confirm the current part number with a Parker distributor before reordering — particularly for MH and HMI cylinders that may have had seal groove revisions that require updated kits.
5. Assuming NFPA interchangeability extends to all dimensions NFPA standardizes mounting and port locations — not rod thread, cushion design, or port size. Cross-referencing Parker to another brand requires verifying all dimensions, not just the NFPA mounting pattern.
Frequently Asked Questions
Q: Are Parker 2H cylinders still manufactured, or have they been discontinued? A: The Parker 2H series remains in active production as of 2026. It is Parker’s core NFPA tie-rod industrial cylinder and among their highest-volume products. There is no indication of discontinuation. Parker periodically updates individual bore configurations — verify current part numbers with a distributor.
Q: What is the difference between Parker 2H and 3H cylinders? A: The 2H is Parker’s standard-duty NFPA tie-rod cylinder, rated to 3,000 PSI, available in 1.5–8.0 in bores. The 3H is a heavy-duty tie-rod cylinder designed for the same NFPA envelope but with heavier barrel walls, larger tie rod diameters, and higher-strength end caps for demanding applications in larger bore sizes (typically 6–24 in). For most applications under 6 in bore, 2H is the appropriate specification.
Q: How do I identify which Parker cylinder series I have? A: Parker cylinders have a nameplate or laser-etched identification on the barrel. The series designation (2H, MH, HMI, etc.), bore size, stroke, and Parker part number are included. If the nameplate is damaged or missing, a Parker distributor can often identify the series from physical dimensions and construction (tie-rod vs. welded, end cap material, mounting style).
Q: What is the Parker cylinder warranty? A: Parker offers a limited warranty on new cylinders covering defects in materials and workmanship. Standard terms are 12 months from date of shipment. Warranty does not cover misapplication, contamination damage, or external physical damage. For current warranty terms, confirm with your authorized Parker distributor.
Q: Can Parker hydraulic cylinders be repaired, or must they be replaced? A: Parker cylinders — particularly the 2H and HMI — are designed to be resealed and rebuilt. Parker offers OEM seal kits for all current series. Repair is cost-effective when chrome plating is intact and barrel bore is in tolerance. MH cylinders require a hydraulic press and qualified rebuild shop for disassembly. See our repair guide for the full repair vs. replace decision framework.
Q: Where can I download Parker hydraulic cylinder catalogs and engineering data? A: Parker publishes full engineering catalogs at parker.com under the Hydraulics > Cylinders section. The 2H catalog (Parker publication HY08-1152-B1) and the engineering selection guide are available as free PDFs and cover bore/stroke options, force tables, and mounting dimension drawings for all standard configurations.
Q: What is Parker’s delivery lead time for non-stock cylinders? A: Standard 2H cylinders in common bore/stroke configurations are typically available from distributor stock in 1–3 business days. Non-stock 2H and HMI configurations are usually 3–10 business days from Parker’s factory. MH series and large-bore cylinders range from 2–8 weeks depending on bore size and configuration. Custom cylinders (non-standard strokes, special materials) typically require 4–16 weeks.
Q: How do Parker cylinder prices compare to alternatives? A: Parker 2H pricing is competitive with Bosch Rexroth and Eaton NFPA cylinders — all three typically fall within 10–15% of each other for equivalent specifications. Prince and smaller domestic manufacturers price 20–35% below Parker for standard applications. The premium for Parker is justified by its distributor network density, seal kit availability, and technical support — factors that matter most when a cylinder fails and you need it back in service today, not next week.
Talk to a Parker Cylinder Distributor
Whether you’re replacing a failed 2H in a production line, specifying an MH series cylinder for a press rebuild, or sourcing HMI cylinders for a mobile equipment OEM program, matching the right series to your application and pressure requirements up front prevents costly misspecification.
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Ready to specify? Have this information available:
- Application type and operating pressure
- Required bore and stroke
- Mounting style (NFPA standard or custom)
- Fluid type and operating temperature range
- Environment (indoor/clean vs. outdoor/severe)
- Required delivery timeline
For cylinder sizing calculations before you contact a distributor, start with our hydraulic cylinder sizing guide. For context on where Parker cylinders fit within the broader cylinder type landscape, see our types overview.
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