[{"data":1,"prerenderedAt":657},["ShallowReactive",2],{"catalog:meta":3,"guides:page:\u002Finjection-molding-machine-parts\u002Fclamp-cylinder\u002Fpiston-rod-nut:*":258,"guides:topics:clamp-cylinder:\u002Finjection-molding-machine-parts\u002Fclamp-cylinder\u002Fpiston-rod-nut:path,title,short":497,"guides:page:\u002Finjection-molding-machine-parts\u002Fclamp-cylinder:diagram":514,"diagram:id:cylinder-seals":515,"catalog:parts::MC-SB-10":646},{"categories":4,"machines":132,"zones":212,"totals":255},[5,35,59,122],{"id":6,"name":7,"slug":8,"description":9,"partCount":10,"subcategories":11},"EC","Electrical Components","electrical","Electrical systems and components for injection molding machines including heaters, thermocouples, servo motors, and controllers.",11,[12,17,22,27,31],{"id":13,"name":14,"slug":15,"partCount":16},"EC-CBC","Circuit Boards & Controllers","circuit-boards",4,{"id":18,"name":19,"slug":20,"partCount":21},"EC-CE","Connectors & Cables","connectors-cables",2,{"id":23,"name":24,"slug":25,"partCount":26},"EC-GEP","Servo Motors & Drives","servo-motors",1,{"id":28,"name":29,"slug":30,"partCount":21},"EC-HT","Heaters","heaters",{"id":32,"name":33,"slug":34,"partCount":21},"EC-SF","Safety Components","safety",{"id":36,"name":37,"slug":38,"description":39,"partCount":40,"subcategories":41},"HY","Hydraulic Components","hydraulic","Complete range of hydraulic system components including pumps, valves, motors, and pressure controls for injection molding machines.",14,[42,46,51,55],{"id":43,"name":44,"slug":45,"partCount":26},"HY-AU","Accumulators","accumulators",{"id":47,"name":48,"slug":49,"partCount":50},"HY-CV","Control Valves","control-valves",6,{"id":52,"name":53,"slug":54,"partCount":26},"HY-MO","Monitors & Gauges","monitors-gauges",{"id":56,"name":57,"slug":58,"partCount":50},"HY-PW","Pumps & Motors","pumps-motors",{"id":60,"name":61,"slug":62,"description":63,"partCount":64,"subcategories":65},"MC","Mechanical Components","mechanical","Mechanical parts and assemblies including barrels, screws, tie bars, bushings, platens, and clamping components.",42,[66,71,75,80,85,89,93,97,101,105,109,114,118],{"id":67,"name":68,"slug":69,"partCount":70},"MC-BC","Barrels & Cylinders","barrels-cylinders",5,{"id":72,"name":73,"slug":74,"partCount":16},"MC-SB","Screw Barrels & Seals","screws",{"id":76,"name":77,"slug":78,"partCount":79},"MC-TC","Tie Bars & Columns","tie-bars",7,{"id":81,"name":82,"slug":83,"partCount":84},"MC-GZ","Bushings & Guides","bushings-guides",8,{"id":86,"name":87,"slug":88,"partCount":26},"MC-PP","Platens","platens",{"id":90,"name":91,"slug":92,"partCount":70},"MC-TL","Toggle & Links","toggle-links",{"id":94,"name":95,"slug":96,"partCount":21},"MC-CC","Clamping Components","clamping",{"id":98,"name":99,"slug":100,"partCount":21},"MC-GMP","Tools & Accessories","tools-accessories",{"id":102,"name":103,"slug":104,"partCount":21},"MC-ES","End Caps & Plates","end-caps",{"id":106,"name":107,"slug":108,"partCount":26},"MC-SR","Seals & Rings","seals-rings",{"id":110,"name":111,"slug":112,"partCount":113},"MC-JM","Joints & Mounts","joints-mounts",3,{"id":115,"name":116,"slug":117,"partCount":26},"MC-SG","Safety Guards","safety-guards",{"id":119,"name":120,"slug":121,"partCount":26},"MC-CR","Clamping Mechanism","clamping-mechanism",{"id":123,"name":124,"slug":125,"description":126,"partCount":113,"subcategories":127},"O","Other Components","other","Additional components including filters, cooling systems, lubrication parts, and other auxiliary equipment.",[128],{"id":129,"name":130,"slug":131,"partCount":113},"O-TC","Filters & Cooling","filters-cooling",[133,143,161,172,180,188,194,200,205],{"id":134,"name":135,"slug":134,"series":136,"partCount":142},"haitian","Haitian International",[137,138,139,140,141],"Mars Series (MA)","Jupiter Series (JU)","Zhafir Venus Series (VE)","Zhafir Zeres Series (ZE)","Zhafir Jeres Series (JE)",68,{"id":144,"name":145,"slug":144,"series":146,"partCount":160},"yizumi","Yizumi",[147,148,149,150,151,152,153,154,155,156,157,158,159],"A6 Series","A5-EU Series","A5-N Series","SKIII Series","DP Series","D1 Series","FF Series","FF-M Series","P Series","CG-P Series","VM Series","SPET Series","LSR Series",12,{"id":162,"name":163,"slug":162,"series":164,"partCount":171},"chen-hsong","Chen Hsong",[165,166,167,168,169,170],"JETMASTER MK Series","JETMASTER SVP Series","SUPERMASTER Series","EASYMASTER Series","SPARK Series","JETMASTER C2 Series",10,{"id":173,"name":174,"slug":173,"series":175,"partCount":179},"tederic","Tederic",[176,177,178],"NEO Series","D Series (Two-Platen)","DE Series (All-Electric)",0,{"id":181,"name":182,"slug":181,"series":183,"partCount":179},"borch","Borch",[184,185,186,187],"BU Series (Two-Platen)","BS-III Series (Servo)","BE Series (All-Electric)","BM Series (Multi-color)",{"id":189,"name":190,"slug":189,"series":191,"partCount":179},"log-machine","LOG Machine",[192,193],"LOG-SE Series","LOG-EE Series (All-Electric)",{"id":195,"name":196,"slug":195,"series":197,"partCount":179},"donghua","Donghua",[198,199],"DH Series (Servo)","DH-TP Series (Two-Platen)",{"id":201,"name":202,"slug":201,"series":203,"partCount":179},"sunbun","Sunbun",[204],"Sunbun Servo Series",{"id":206,"name":207,"slug":206,"series":208,"partCount":179},"lijin","L.K. Machinery (Lijin)",[209,210,211],"POTENZA Series","FORZA Series (Two-Platen)","ELETTRICA Series (All-Electric)",[213,217,221,225,228,231,235,238,242,248,251],{"id":214,"number":26,"name":215,"role":216,"partCount":21},"clamp-cylinder","Clamping cylinder","The hydraulic cylinder behind the rear platen. It drives the crosshead that straightens the toggle links, which opens and closes the mold and builds the clamping force.",{"id":218,"number":21,"name":219,"role":220,"partCount":50},"toggle","Toggle mechanism","Links, pins and bushings between the rear and moving platens. They multiply the force of the clamping cylinder and lock the mold shut while plastic is injected.",{"id":222,"number":113,"name":223,"role":224,"partCount":113},"ejector","Ejector","A small cylinder behind the moving platen that pushes the ejector rods and plate forward to release the finished part from the mold.",{"id":78,"number":16,"name":226,"role":227,"partCount":40},"Tie bars & bushings","Four steel columns that join the platens, guide the moving platen and carry the clamping force. Tie bar nuts lock them in place; bushings guide the moving platen along them.",{"id":88,"number":70,"name":229,"role":230,"partCount":21},"Platens & mold plates","The fixed and moving platens carry the two halves of the mold; the rear platen anchors the toggle. Locating rings and clamping plates center and hold the mold.",{"id":232,"number":50,"name":233,"role":234,"partCount":50},"barrel-screw","Barrel, screw & nozzle","The screw turns inside the heated barrel to melt and mix the plastic, then moves forward to inject it through the nozzle into the mold. The screw tip and check ring stop melt from flowing back.",{"id":30,"number":79,"name":236,"role":237,"partCount":113},"Heater bands & sensors","Heater bands around the barrel and nozzle melt the plastic. Thermocouples measure each heating zone so the controller can hold the set temperature.",{"id":239,"number":84,"name":240,"role":241,"partCount":79},"injection-unit","Injection unit","Injection cylinders push the screw forward, the hydraulic (plasticizing) motor turns it, and the carriage moves the unit against the mold on its guide rails.",{"id":243,"number":244,"name":245,"role":246,"partCount":247},"hydraulics",9,"Hydraulic unit","The pump, motor, valves, accumulator, filters and oil cooler in the machine base. They supply and control the oil pressure for every movement of the machine.",16,{"id":8,"number":171,"name":249,"role":250,"partCount":244},"Electrical cabinet","The controller, I\u002FO and drive boards, servo drives, contactors and safety switches that run and protect the machine.",{"id":252,"number":10,"name":253,"role":254,"partCount":21},"feet","Machine feet","Leveling bolts and anti-vibration pads under the machine base that keep the machine level and stop vibration spreading to the floor.",{"parts":256,"subcategories":257},70,23,{"id":259,"title":260,"body":261,"description":469,"diagram":470,"extension":471,"faq":472,"item":485,"lastModified":486,"meta":487,"navigation":488,"order":16,"parts":489,"path":491,"seo":492,"seoTitle":493,"short":494,"stem":495,"__hash__":496},"guides\u002Finjection-molding-machine-parts\u002Fclamp-cylinder\u002Fpiston-rod-nut.md","Piston rod nut of a hydraulic cylinder",{"type":262,"value":263,"toc":459},"minimark",[264,268,273,276,280,283,312,315,319,357,360,364,378,382,389,410,414,427,431,448],[265,266,267],"p",{},"The piston rod nut is the nut that holds the piston on the threaded end of the piston rod, inside a hydraulic cylinder. In the usual design the piston sits against a shoulder on the rod and the nut clamps it from the other side, so the nut carries the full force whenever the cylinder pulls back, for example when the clamping cylinder breaks the mold open. It is locked so it cannot turn. A rod nut that works loose lets the piston knock on the rod, which damages the seals and the threads and, in the worst case, lets the piston come off.",[269,270,272],"h2",{"id":271},"where-the-rod-nut-sits","Where the rod nut sits",[265,274,275],{},"In the drawing, the piston rod nut is on the end of the rod, against the rear face of the piston, inside the cylinder. You cannot see it or check it without opening the cylinder, so it is inspected whenever the seals are replaced. The same arrangement is used in the clamping, injection and ejector cylinders, although some cylinders have a piston that screws directly onto the rod and is pinned instead.",[269,277,279],{"id":278},"how-the-nut-is-locked","How the nut is locked",[265,281,282],{},"The locking method depends on the cylinder maker. Common ones are:",[284,285,286,294,300,306],"ul",{},[287,288,289,293],"li",{},[290,291,292],"strong",{},"Thread-locking adhesive"," on the rod thread.",[287,295,296,299],{},[290,297,298],{},"A set screw"," through the nut, pressing on the rod or into a recess.",[287,301,302,305],{},[290,303,304],{},"A tab washer"," bent over a flat of the nut, or a second nut tightened against the first.",[287,307,308,311],{},[290,309,310],{},"A pin or split pin"," through the nut and the rod.",[265,313,314],{},"The machine manual gives the tightening torque and the locking method. Refit the same type of locking when you reassemble, and never leave it out.",[269,316,318],{"id":317},"signs-of-a-loose-or-damaged-rod-nut","Signs of a loose or damaged rod nut",[284,320,321,327,333,345,351],{},[287,322,323,326],{},[290,324,325],{},"Knocking"," or a clunk at each change of direction, or when the cylinder starts to move.",[287,328,329,332],{},[290,330,331],{},"Lost motion",": the rod starts to move a moment after the valve switches.",[287,334,335,338,339,344],{},[290,336,337],{},"Piston seals that keep failing",", or seal fragments in the ",[340,341,343],"a",{"href":342},"\u002Finjection-molding-machine-parts\u002Fhydraulics\u002Foil-filter\u002F","oil filter",".",[287,346,347,350],{},[290,348,349],{},"Metal particles"," in the filter or on the magnetic drain plug.",[287,352,353,356],{},[290,354,355],{},"No movement in one direction",": the nut has come off and the piston has separated from the rod. Stop the machine.",[265,358,359],{},"Knocking can also come from a speed profile that does not slow the movement before the end of the stroke, so check the settings first.",[269,361,363],{"id":362},"why-rod-nuts-work-loose","Why rod nuts work loose",[284,365,366,369,372,375],{},[287,367,368],{},"The nut was not tightened to the specified torque, or the locking was left out or not renewed at the last repair.",[287,370,371],{},"Shock loads: the piston hitting the end of the cylinder at speed, or pressure peaks from fast valve switching.",[287,373,374],{},"Damaged or stretched threads on the nut or the rod.",[287,376,377],{},"Reused locking parts: a tab washer bent for the second time, or old adhesive left in the thread.",[269,379,381],{"id":380},"inspecting-and-replacing-the-rod-nut","Inspecting and replacing the rod nut",[265,383,384,385,344],{},"The nut is reached by taking the rod and piston out of the cylinder, as described in ",[340,386,388],{"href":387},"\u002Finjection-molding-machine-parts\u002Fclamp-cylinder\u002Fcylinder-seal-replacement\u002F","replacing cylinder seals",[390,391,392,395,398,401,404,407],"ol",{},[287,393,394],{},"Release the locking first: remove the set screw or pin, straighten the tab washer, or follow the adhesive maker's instructions for loosening.",[287,396,397],{},"Hold the rod without marking the chrome, using soft jaws or the flats on the rod end if it has them, and undo the nut.",[287,399,400],{},"Inspect the threads on the nut and the rod for damage, stretching and corrosion, and the nut and piston faces for marks that show the piston has been moving.",[287,402,403],{},"Replace the nut if its thread or faces are damaged or its locking feature is worn. If the rod thread is damaged, the rod needs repair or replacement.",[287,405,406],{},"Clean the threads, remove old adhesive, fit the piston with a new O-ring, and tighten the nut to the torque in the manual.",[287,408,409],{},"Lock it again with new locking parts.",[269,411,413],{"id":412},"the-piston-rod-nut-we-supply","The piston rod nut we supply",[265,415,416,417,421,422,426],{},"The ",[340,418,420],{"href":419},"\u002Fparts\u002Fmc-sb-10\u002F","piston rod nut"," we supply is made for the injection cylinder of Haitian MA, PL and HTF series machines. It measures 48 × 20 mm with an M22 × 2.5 thread, in 45# steel or alloy steel with a black oxide finish. Clamping and ejector cylinders use the same principle but different sizes, so always compare a replacement with the old nut. The nut and the ",[340,423,425],{"href":424},"\u002Finjection-molding-machine-parts\u002Fclamp-cylinder\u002Fpiston-seals\u002F","piston seals"," are usually renewed at the same time.",[269,428,430],{"id":429},"what-to-send-for-a-replacement-quote","What to send for a replacement quote",[390,432,433,436,439,442,445],{},[287,434,435],{},"The machine brand and model, and which cylinder the nut comes from.",[287,437,438],{},"The thread size and pitch, measured with a thread gauge.",[287,440,441],{},"The outside diameter or the size across the flats, and the thickness.",[287,443,444],{},"How the nut is locked: set screw, pin, tab washer or adhesive.",[287,446,447],{},"Photos of the nut and the rod end, and any markings.",[265,449,450,454,455,344],{},[340,451,453],{"href":452},"\u002Frequest-quote\u002F","Request a quote",". For the other parts of the cylinder, see the ",[340,456,458],{"href":457},"\u002Finjection-molding-machine-parts\u002Fclamp-cylinder\u002F","clamping cylinder guide",{"title":460,"searchDepth":21,"depth":21,"links":461},"",[462,463,464,465,466,467,468],{"id":271,"depth":21,"text":272},{"id":278,"depth":21,"text":279},{"id":317,"depth":21,"text":318},{"id":362,"depth":21,"text":363},{"id":380,"depth":21,"text":381},{"id":412,"depth":21,"text":413},{"id":429,"depth":21,"text":430},"What the piston rod nut does inside an injection molding machine hydraulic cylinder, how it is locked, the signs of a loose nut, and how to inspect and replace it.","cylinder-seals","md",[473,476,479,482],{"question":474,"answer":475},"What does a piston rod nut do?","It holds the piston on the threaded end of the piston rod inside a hydraulic cylinder. In the usual design the piston sits against a shoulder on the rod and the nut clamps it from the other side, so the nut carries the load whenever the cylinder pulls back.",{"question":477,"answer":478},"What happens if the piston rod nut comes loose?","The piston can move on the rod, which causes knocking at each change of direction, damages the piston seals and the threads, and can leave metal particles in the oil. If the nut comes off completely, the piston separates from the rod and the cylinder stops working in one direction.",{"question":480,"answer":481},"Can a piston rod nut be reused?","It can be reused if its thread, its faces and its locking feature are undamaged. Locking parts such as tab washers, and thread-locking adhesive, should always be renewed.",{"question":483,"answer":484},"Which piston rod nut fits my machine?","Nuts differ in size and thread from cylinder to cylinder, even on the same machine. Measure the thread size and pitch, the outside size and the thickness of the old nut, note how it was locked, and give the machine model and which cylinder it comes from.","rod-nut","2026-11-01",{},true,[490],"MC-SB-10","\u002Finjection-molding-machine-parts\u002Fclamp-cylinder\u002Fpiston-rod-nut",{"title":260,"description":469},"Piston Rod Nut: Function, Locking and Replacement","Piston rod nut","injection-molding-machine-parts\u002Fclamp-cylinder\u002Fpiston-rod-nut","e_IxlZzbHNZSEJpEc0DVAjXMVk23P-XilpubPh8PRPY",[498,502,506,510],{"path":499,"title":500,"short":501},"\u002Finjection-molding-machine-parts\u002Fclamp-cylinder\u002Fpiston-seals","Hydraulic cylinder piston seals and Y-rings","Piston seals",{"path":503,"title":504,"short":505},"\u002Finjection-molding-machine-parts\u002Fclamp-cylinder\u002Frod-seals","Rod seals and wiper seals of a hydraulic cylinder","Rod seals and wipers",{"path":507,"title":508,"short":509},"\u002Finjection-molding-machine-parts\u002Fclamp-cylinder\u002Fcylinder-seal-replacement","Replacing the seals of an injection molding machine cylinder","Replacing cylinder seals",{"path":511,"title":512,"short":513},"\u002Finjection-molding-machine-parts\u002Fclamp-cylinder\u002Fauxiliary-cylinder","Auxiliary hydraulic cylinder of an injection molding machine","Auxiliary cylinder",{"diagram":214},{"diagram":516},{"title":517,"description":518,"items":519},"Seals of a hydraulic cylinder","Section through a hydraulic cylinder showing the piston seals, piston rod nut, piston rod and rod seal set, with a screw barrel assembly below, numbered.",[520,537,550,564,581,596,614],{"id":521,"name":522,"role":523,"subcategory":94,"marker":524,"shapes":528},"cylinder","Cylinder tube and end caps","The honed tube and the end caps hold the oil. Oil pumped into one end or the other moves the piston.",[525,526,525,527],100,24,66,{"solid":529},[530,531,532,533,534,535,536],"M39 56h22a3 3 0 0 1 3 3v162a3 3 0 0 1 -3 3h-22a3 3 0 0 1 -3 -3v-162a3 3 0 0 1 3 -3z","M64 66h352v14h-352z","M64 200h352v14h-352z","M419 56h46a3 3 0 0 1 3 3v53a3 3 0 0 1 -3 3h-46a3 3 0 0 1 -3 -3v-53a3 3 0 0 1 3 -3z","M419 165h46a3 3 0 0 1 3 3v53a3 3 0 0 1 -3 3h-46a3 3 0 0 1 -3 -3v-53a3 3 0 0 1 3 -3z","M44 44h14v12h-14z","M392 54h14v12h-14z",{"id":485,"name":494,"role":538,"parts":539,"marker":540,"shapes":544},"Holds the piston on the threaded end of the rod. It must stay tight: a loose nut lets the piston knock and damages the seals.",[490],[541,526,542,543],150,176,117,{"solid":545,"line":547},[546],"M172 117h22a2 2 0 0 1 2 2v42a2 2 0 0 1 -2 2h-22a2 2 0 0 1 -2 -2v-42a2 2 0 0 1 2 -2z",[548,549],"M170 129L196 129","M170 151L196 151",{"id":551,"name":552,"role":553,"marker":554,"shapes":558},"piston","Piston","Separates the two oil chambers of the cylinder. Pressure on one side pushes it, and the rod with it.",[555,526,556,557],198,200,96,{"solid":559,"hidden":561},[560],"M199 82h60a3 3 0 0 1 3 3v110a3 3 0 0 1 -3 3h-60a3 3 0 0 1 -3 -3v-110a3 3 0 0 1 3 -3z",[562,563],"M196 124L262 124","M196 156L262 156",{"id":565,"name":501,"role":566,"parts":567,"marker":569,"shapes":573},"piston-seals","Y-rings and wear rings in the piston grooves. They keep oil from passing the piston; worn piston seals make the cylinder creep and lose force.",[568],"MC-SB-08",[570,526,571,572],246,249,80,{"solid":574},[575,576,577,578,579,580],"M202 80L216 80L216 90L211.8 90L209 85L206.2 90L202 90Z","M242 80L256 80L256 90L251.8 90L249 85L246.2 90L242 90Z","M202 200L216 200L216 190L211.8 190L209 195L206.2 190L202 190Z","M242 200L256 200L256 190L251.8 190L249 195L246.2 190L242 190Z","M222 80h14v6h-14z","M222 194h14v6h-14z",{"id":582,"name":583,"role":584,"parts":585,"marker":587,"shapes":590},"piston-rod","Piston rod","Chrome-plated rod that carries the force out of the cylinder. Scratches or pitting on its surface quickly destroy the rod seals.",[586],"MC-GZ-01",[588,526,588,589],330,115,{"solid":591,"line":594},[592,593],"M262 115h276v50h-276z","M546 108h18a8 8 0 0 1 8 8v48a8 8 0 0 1 -8 8h-18a8 8 0 0 1 -8 -8v-48a8 8 0 0 1 8 -8z",[595],"M544 140a11 11 0 1 0 22 0a11 11 0 1 0 -22 0z",{"id":597,"name":598,"role":599,"parts":600,"marker":602,"shapes":606},"rod-seals","Rod seal set","Guide ring, rod seal and wiper in the front head. The seal holds the oil in, the wiper keeps dirt out and the guide ring keeps the rod centred.",[601],"MC-SB-07",[603,526,604,605],492,472,112,{"solid":607},[608,609,610,611,612,613],"M422 110h14v5h-14z","M422 165h14v5h-14z","M442 106L454 106L454 115L450.4 115L448 110.5L445.6 115L442 115Z","M442 174L454 174L454 165L450.4 165L448 169.5L445.6 165L442 165Z","M458 107L468 107L468 110L473 115L458 115Z","M458 173L468 173L468 170L473 165L458 165Z",{"id":615,"name":616,"role":617,"parts":618,"marker":620,"shapes":624},"screw-barrel","Screw barrel assembly","The barrel and screw supplied together as a matched set, with the screw head, ready to fit to the injection unit.",[619],"MC-SB-01",[621,622,621,623],420,336,292,{"solid":625,"hidden":630},[626,627,628,629],"M148 276L162 271L176 271L176 287L162 287L148 282Z","M178 262h6a2 2 0 0 1 2 2v30a2 2 0 0 1 -2 2h-6a2 2 0 0 1 -2 -2v-30a2 2 0 0 1 2 -2z","M186 266h280v26h-280z","M468 272h32a2 2 0 0 1 2 2v10a2 2 0 0 1 -2 2h-32a2 2 0 0 1 -2 -2v-10a2 2 0 0 1 2 -2z",[631,632,633,634,635,636,637,638,639,640,641,642,643,644,645],"M190 279L462 279","M196 269L202 289","M215 269L221 289","M234 269L240 289","M253 269L259 289","M272 269L278 289","M291 269L297 289","M310 269L316 289","M329 269L335 289","M348 269L354 289","M367 269L373 289","M386 269L392 289","M405 269L411 289","M424 269L430 289","M443 269L449 289",[647],{"partNumber":490,"name":648,"subcategory":72,"subcategoryName":649,"shortDescription":650,"inStock":488,"zone":239,"compatibleMachines":651},"Piston Rod Nut","Cylinders & Seals","Injection cylinder piston rod nut for Haitian and equivalent injection molding machines.",[652,653,654,655,656],"Haitian MA Series","Haitian MA II Series","Haitian MA III Series","Haitian PL Series","Haitian HTF Series",1793548978298]