{"id":2543,"date":"2026-07-01T06:03:16","date_gmt":"2026-07-01T06:03:16","guid":{"rendered":"https:\/\/hydrauliccylindersprice.com\/product\/small-excavator-boom-cylinder\/"},"modified":"2026-07-01T06:03:18","modified_gmt":"2026-07-01T06:03:18","slug":"small-excavator-boom-cylinder","status":"publish","type":"product","link":"https:\/\/hydrauliccylindersprice.com\/et\/toode\/small-excavator-boom-cylinder\/","title":{"rendered":"Small Excavator Boom Cylinder"},"content":{"rendered":"

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\n \"Small<\/p>\n
\n Small Excavator \u00b7 3rd of 5<\/span><\/p>\n

Small Excavator Boom Cylinder<\/h2>\n

The heavy lifter. The boom cylinder carries everything \u2014 boom, stick, bucket, and payload \u2014 against gravity on every lift stroke. The largest bore, largest rod, and highest thrust in the small excavator cylinder family. When the operator swings a loaded bucket from trench to truck, this cylinder holds the entire weight steady.<\/p>\n

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50\u2013125mm<\/span>Largest Bore<\/span><\/div>\n
361 KN<\/span>Highest Thrust<\/span><\/div>\n
29.4 MPa<\/span>Pressure<\/span><\/div>\n
\u22641,000mm<\/span>Stroke<\/span><\/div>\n<\/p><\/div>\n<\/p><\/div>\n<\/section>\n

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Fighting Gravity \u2014 The Only Excavator Cylinder That Carries the Entire Arm<\/span><\/h2>\n

\"Boom<\/p>\n

\n \"Small<\/p>\n

The bucket cylinder (#1) only supports the weight of the bucket and its contents. The stick cylinder (#2) supports the stick plus the bucket assembly. The boom cylinder supports everything: the boom structure itself (the heaviest individual component), the stick assembly, the bucket, and whatever the bucket is carrying \u2014 soil, rock, concrete, or pipe. On a 10-tonne excavator, this combined weight can reach 2,000\u20133,000 kg at the boom tip.<\/p>\n<\/div>\n

This gravitational load is continuous \u2014 the boom cylinder must hold the arm at any elevation angle without drift, even when the operator releases the joystick. A boom that drifts downward (from internal cylinder leakage or valve seepage) is a safety hazard and a productivity killer: the operator must constantly re-lift the arm, wasting fuel and time.<\/p>\n

The 361 KN maximum thrust \u2014 42% more than the bucket cylinder and 18% more than the stick cylinder \u2014 reflects this gravitational burden. Korea Ever-Power specifies the boom cylinder with tight internal leakage limits to ensure drift-free hold at any boom angle. Browse the full small excavator hydraulic cylinder<\/a> range.<\/p>\n

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Technical Specifications<\/span><\/h2>\n
\n\n\n\n\n\n\n\n\n\n\n\n\n
Parameter<\/th>\nSpecification<\/th>\n<\/tr>\n<\/thead>\n
Product<\/td>\nSmall Excavator Boom Cylinder<\/td>\n<\/tr>\n
Function<\/td>\nControl the lifting motion of the big arm (boom)<\/td>\n<\/tr>\n
Bore Diameter<\/td>\n50 mm \u2013 125 mm<\/td>\n<\/tr>\n
Rod Diameter<\/td>\n25 mm \u2013 75 mm<\/td>\n<\/tr>\n
Stroke<\/td>\n\u2264 1,000 mm<\/td>\n<\/tr>\n
Max Thrust<\/td>\n361 KN (bore 125 mm \/ 29.4 MPa)<\/td>\n<\/tr>\n
Application<\/td>\nSmall Excavator (1\u201310 tonne class)<\/td>\n<\/tr>\n
Certification<\/td>\nISO 9001 \u00b7 100% hydrostatic tested \u00b7 drift tested<\/td>\n<\/tr>\n<\/tbody>\n<\/table><\/div>\n<\/section>\n

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Lifting vs Lowering \u2014 Asymmetric Forces, Asymmetric Engineering<\/h2>\n

The boom cylinder’s lifting and lowering strokes face fundamentally different loading conditions:<\/p>\n

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\n Lifting \u2014 maximum force, moderate speed<\/strong><\/p>\n

The cylinder extends against the full gravitational load of the arm assembly plus the payload. This is the boom cylinder’s peak force demand \u2014 361 KN at 29.4 MPa and 125 mm bore. The lifting speed is limited by the pump flow rate and the operator’s desire for smooth, controlled placement. Hydraulic energy flows from the pump to the cylinder \u2014 positive work output.<\/p>\n<\/p><\/div>\n<\/p><\/div>\n

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\n Lowering \u2014 gravity-assisted, energy-absorbing<\/strong><\/p>\n

Gravity pulls the arm downward \u2014 the boom cylinder retracts under the arm’s own weight. The cylinder does not need to produce force; it needs to control the rate at which the arm descends. The lowering valve on the boom circuit meters the oil flow out of the cylinder, converting the arm’s gravitational potential energy into heat in the oil. Boom-down speed is a safety parameter: too fast, and the arm slams into the ground. Contact Korea Ever-Power engineering<\/a> for boom cylinder specifications.<\/p>\n<\/p><\/div>\n<\/p><\/div>\n<\/p><\/div>\n<\/p><\/div>\n<\/section>\n

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\n \"Excavator
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The Best-Protected Cylinder on the Excavator \u2014 High and Shielded<\/span><\/h2>\n

The bucket cylinder operates at ground level, caked in dirt and hit by rocks. The stick cylinder sits at mid-height, partially exposed. The boom cylinder mounts high on the machine \u2014 between the superstructure and the boom root \u2014 well above the working surface. Its rod and barrel are shielded from direct ground contact, debris packing, and water immersion by the boom structure itself.<\/p>\n

This protected position means the boom cylinder’s primary durability challenge is not contamination (as it is for the bucket cylinder) but fatigue. The boom cylinder handles the heaviest gravitational load on every cycle \u2014 lift loaded, swing, dump, lower empty, swing back, dig \u2014 thousands of full-load lift cycles per shift. The barrel, rod, welds, and eye bearings must all be designed for fatigue life exceeding the excavator’s planned operating life (typically 10,000\u201315,000 hours for a small excavator).<\/p>\n

Chrome plating is 50 \u00b5m (adequate for the protected position \u2014 less than the 80 \u00b5m used on the ground-level bucket cylinder). Bore finish Ra 0.2\u20130.4 \u00b5m. Rod eyes forged and machined. Seals rated -30 \u00b0C to +80 \u00b0C. Every boom cylinder is hydrostatic tested at 1.5\u00d7 rated pressure (44.1 MPa) and drift-tested \u2014 verifying that the boom holds position without creeping downward over a defined period under rated load.<\/p>\n<\/section>\n

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OEM & ODM<\/span><\/h2>\n
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What You Provide<\/strong><\/div>\n
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Excavator model and weight class, boom length and weight, combined arm-assembly weight (boom + stick + bucket + rated payload), required lifting force, lowering speed requirement, bore\/rod\/stroke, system pressure, drift limit specification, pin diameters, and the boom pivot assembly drawing.<\/p>\n<\/div><\/div>\n

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What the Factory Delivers<\/strong><\/div>\n
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Engineering drawing with bore, rod (forged eyes), stroke, fatigue-rated barrel, seal specification, chrome plating detail, and mounting dimensions. Hydrostatic + drift test certificate. Seal kits. Browse the mobile machinery hydraulic cylinder family<\/a> and the Korea Ever-Power catalogue<\/a>.<\/p>\n<\/div><\/div>\n<\/p><\/div>\n

\"Korea
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FAQ<\/span><\/h2>\n
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Why does the boom cylinder have the largest bore in the family?<\/h3>\n

Because the boom cylinder carries the combined weight of the entire arm assembly. The bucket cylinder only supports the bucket (lightest); the stick cylinder supports the stick + bucket (medium); the boom cylinder supports everything (heaviest). A larger bore produces more force from the same system pressure \u2014 the 125 mm bore at 29.4 MPa generates 361 KN, enough to lift the full arm assembly plus rated payload at the worst-case (most horizontal) boom angle.<\/p>\n<\/p><\/div>\n

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What causes boom drift, and how is it tested?<\/h3>\n

Boom drift \u2014 the slow downward creep of the arm when the joystick is in neutral \u2014 is caused by internal oil leakage past the piston seal, or external leakage through the control valve. Korea Ever-Power tests every boom cylinder for drift by loading the cylinder to rated force, isolating the ports, and monitoring the piston position over a 10-minute hold period. The maximum permitted drift is specified by the excavator OEM \u2014 typically \u22645 mm in 10 minutes at rated load.<\/p>\n<\/p><\/div>\n

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Does the boom cylinder use the same seals as the bucket and stick cylinders?<\/h3>\n

Same seal material (polyurethane piston seal, NBR rod seal) but the wiper specification differs. The bucket cylinder (#1) uses a heavy-duty double-lip wiper with hardened scraper (for ground-level debris). The boom cylinder uses a standard double-lip wiper \u2014 adequate for its protected, elevated position. Korea Ever-Power standardises the piston seal and rod seal across all three cylinders for a given excavator model, simplifying the OEM’s seal-kit inventory. Browse telescopic cylinders<\/a> and forklift cylinders<\/a>.<\/p>\n<\/p><\/div>\n<\/p><\/div>\n<\/section>\n

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Related Categories<\/span><\/h2>\n
<\/p>\n
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\"Telescopic\"<\/div>\n
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Telescopic Hydraulic Cylinders \u2192<\/div>\n
Dump truck, trailer, hoist.<\/div>\n<\/div>\n<\/div>\n

<\/a><\/p>\n

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\"Forklift\"<\/div>\n
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Forklift Hydraulic Cylinders \u2192<\/div>\n
Lift, tilt, steer \u2014 OEM.<\/div>\n<\/div>\n<\/div>\n

<\/a><\/p>\n

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\"AWV\"<\/div>\n
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Aerial Work Vehicle Cylinders \u2192<\/div>\n
Scissor, boom, platforms.<\/div>\n<\/div>\n<\/div>\n

<\/a><\/div>\n<\/section>\n

<\/main><\/p>","protected":false},"excerpt":{"rendered":"

Small excavator boom cylinder \u2014 the hydraulic actuator that lifts and lowers the entire arm assembly (boom + stick + bucket) on 1\u201310 tonne mini and small excavators. The largest bore (50\u2013125 mm), largest rod (25\u201375 mm), and highest thrust (361 KN) in the small excavator family \u2014 because the boom cylinder carries the combined gravitational weight of every component attached to it: the boom itself, the stick, the bucket, and whatever the bucket is holding. The boom cylinder works against gravity on every lift. Korea Ever-Power. ISO 9001. OEM & ODM.<\/div>","protected":false},"featured_media":2544,"comment_status":"closed","ping_status":"open","template":"","meta":{"_et_pb_use_builder":"","_et_pb_old_content":"","_et_gb_content_width":""},"product_brand":[],"product_cat":[854],"product_tag":[],"class_list":["post-2543","product","type-product","status-publish","has-post-thumbnail","product_cat-mobile-machinery-hydraulic-cylinders","pa_editor-cxm","first","instock","product-type-simple"],"_links":{"self":[{"href":"https:\/\/hydrauliccylindersprice.com\/et\/wp-json\/wp\/v2\/product\/2543","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/hydrauliccylindersprice.com\/et\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/hydrauliccylindersprice.com\/et\/wp-json\/wp\/v2\/types\/product"}],"replies":[{"embeddable":true,"href":"https:\/\/hydrauliccylindersprice.com\/et\/wp-json\/wp\/v2\/comments?post=2543"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/hydrauliccylindersprice.com\/et\/wp-json\/wp\/v2\/media\/2544"}],"wp:attachment":[{"href":"https:\/\/hydrauliccylindersprice.com\/et\/wp-json\/wp\/v2\/media?parent=2543"}],"wp:term":[{"taxonomy":"product_brand","embeddable":true,"href":"https:\/\/hydrauliccylindersprice.com\/et\/wp-json\/wp\/v2\/product_brand?post=2543"},{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/hydrauliccylindersprice.com\/et\/wp-json\/wp\/v2\/product_cat?post=2543"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/hydrauliccylindersprice.com\/et\/wp-json\/wp\/v2\/product_tag?post=2543"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}