Hydraulic ram (single-acting, spring- or load-return)
Single-acting hydraulic ram · Force from effective area and pressure, oil volume per stroke, spring or load return, rated-capacity rules
A hydraulic ram, as used on this page, is a single-acting cylinder: oil from a hand or power pump enters through one port and pushes the plunger out, and a built-in spring, gravity or the load pushes it back when the pressure is released. Rams are used for pressing, lifting, pushing and holding in workshops, presses and heavy equipment. Ask three things first: the force needed and the pressure of the pump that will drive it, the stroke and the oil volume that stroke takes, and how the ram returns and is secured under load.
Single-acting hydraulic rams and plunger cylinders, spring-return and load-return, including portable rams driven by hand or power pumps and custom rams built to drawing. Double-acting single-rod cylinders, where oil drives both extension and retraction, are covered on the Hydraulic cylinder page. Telescopic multi-stage cylinders and hydraulic pumps sold alone are outside this page.
CNFX editorial research · Sources checked October 12, 2026 · 3 sources
Size the force from effective area and pump pressure
Metro Hydraulic's listing of Enerpac RC-series single-acting cylinders gives the 5-ton models (RC-50 to RC-59) an effective area of 0.99 in², a maximum capacity of 4.9 tons and strokes from 0.63 to 9.13 in, and the 10-ton models (RC-101 to RC-106) an area of 2.24 in², a maximum capacity of 11.2 tons and strokes from 1.00 to 6.13 in. Oil capacity rises with stroke: 0.62 in³ for the RC-50, 9.07 in³ for the RC-59 and 13.70 in³ for the RC-106. [1]
Editorial calculation: 2.24 in² × 10,000 psi = 22,400 lbf, which is 11.2 short tons, matching the listed maximum capacity; 0.99 in² × 10,000 psi = 9,900 lbf ≈ 4.95 short tons against the listed 4.9 tons. Oil per stroke is area × stroke: 2.24 × 6.13 ≈ 13.7 in³ (about 225 cm³) for the RC-106, which is the usable oil a hand pump reservoir must supply. The 10,000 psi pump pressure is an assumption equal to 700 bar. [1]
JW Hydraulic, which builds rams to customers' drawings, lists bores from 40 to 1,200 mm, rods from 12 to 500 mm, strokes up to 15,500 mm, weights up to 60 tons and working pressure up to 700 bar, in carbon, alloy or stainless steel with chrome, nickel or ceramic plating. [2] Editorial note: quote the force at the pressure your pump actually delivers, not the ram's maximum.
Give the supplier the force needed, the pump and its maximum pressure, the stroke and closed height available, how the ram is mounted and how the load bears on the plunger (centred or side load), the return method, duty cycle, environment (outdoor, freezing, corrosive), and any marking or inspection records you need.
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Plan the return and how the load is secured
In a single-acting ram the return is not powered by oil. Metro Hydraulic's RC-series listing describes heavy-duty return springs, design for use in all positions, collar and plunger threads and base mounting holes for fixturing (the listing notes these are not on every model), a baked enamel finish, optional nickel plating, and a CR-400 coupler with dust cap. [1]
For hydraulic jacks used in construction, OSHA 29 CFR 1926.305 requires the manufacturer's rated capacity to be legibly marked and not exceeded, a positive stop to prevent overtravel, blocking or cribbing under the base where a firm foundation is needed, and cribbing or blocking of the load as soon as it has been raised. Jacks exposed to freezing temperatures must hold adequate antifreeze liquid, and inspections are required at least every 6 months for use at one locality, when sent out and returned for special work, and immediately before and after abnormal load or shock. [3]
Editorial note: a spring return retracts the plunger only against light resistance; for long or heavy rams that rely on the load to return, ask how retraction speed is limited when pressure is released.
Effective area, stroke, maximum pressure and return method for a single-acting ram
Force comes from effective area times the pressure your pump delivers, so give the pump pressure: the RC 10-ton models list 2.24 in² of effective area. [1]
2 companies list this product among what they make. Company figures are quoted from each
company's own website; every card states where the relationship came from.
JW HYDRAULIC LIMITED
Manufacturing site to be confirmed for the order
Lists custom hydraulic ram cylinders and marine hydraulic rams built to customers' drawings.
Explore company information and manufacturing capabilities, then discuss the scope of your project with a relevant supplier.
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Compiled and source-reviewed by the CNFX editorial team.
Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review
· Page last updated 13 October 2026
Buyer questions
What is the difference between a hydraulic ram and a double-acting cylinder?
A ram is single-acting: oil extends it through one port and a spring or the load returns it. Double-acting cylinders are covered on the Hydraulic cylinder page. [1]
How much force does a 10-ton RC ram give?
Metro Hydraulic lists 2.24 in² effective area and 11.2 tons maximum capacity, which equals 2.24 in² × 10,000 psi. [1]
What safety rules apply when a ram is used as a jack?
OSHA 29 CFR 1926.305 requires marked rated capacity, a positive stop, blocking, and inspection at least every 6 months. [3]
Sources and what still needs a direct check
Sources checked 2026-10-12. Metro Hydraulic is a distributor listing Enerpac's RC-series data; JW Hydraulic is a cylinder maker describing its custom range; 29 CFR 1926.305 is the US OSHA rule for jacks in construction.
