Engineering references for rod ends, bearings and linkage parts
Practical articles on choosing, sizing, fitting, locking and replacing rod ends, spherical bearings, clevises, linkage rods, tube adapters, bushings and weld-on ball joints.
98articles
10topics
1RFQ guide
K01
Industrial Rod Ends
Specifying male and female rod ends, load ratings, thread strength, misalignment and material for machine linkages.
9 articles
- Q1-01 How Do You Specify a Male or Female Rod End, and How Do You Choose Right-Hand, Left-Hand or Both Threads for an Adjustable Linkage?
- Q1-02 How Do You Size a Rod End for the Radial and Axial Loads in Your Machine: Ratings, Safety Factor, Shock and Reversing Loads?
- Q1-03 How Strong Is the Shank of a Male Rod End: Thread Tension, Bending, Fatigue and Breakage?
- Q1-04 Should I Choose a PTFE-Lined, Metal-to-Metal or Bronze-Race Rod End for Machine Duty?
- Q1-05 What Bore, Bolt, Pin Tolerance and Mounting Arrangement Should You Use for a Rod End: Single or Double Shear, Spacers and Clamping the Inner Ring?
- Q1-06 How Do You Find the Misalignment Angle a Rod End Needs, and the Angle It Really Has Once It Is Installed?
- Q1-07 Which Rod End Material and Finish Suits Wet, Corrosive or Washdown Service: Zinc-Plated Steel, Alloy Steel or Stainless?
- Q1-08 What Grease Does a Relubricatable Rod End Need, How Often, and How Do You Grease It Properly?
- Q1-09 Why Does a Rod End Wear, Develop Play, Bind, Squeak or Seize, and How Do I Find the Cause?
K02
Spherical Plain Bearings
Reading part numbers, choosing steel-on-steel or maintenance-free bearings, clearance, lubrication, fits and replacement.
14 articles
- Q1-01 What Do GE, GEH, GEG and GEEW Mean on a Spherical Plain Bearing, and What Do the Suffixes ES, 2RS and TX Mean?
- Q1-02 How Do You Choose Between a Steel-on-Steel and a Maintenance-Free (PTFE-Lined) Spherical Plain Bearing?
- Q1-03 How Do You Size a Spherical Plain Bearing: Load Ratings, Safety Factor, Shock and Reversing Loads?
- Q1-04 How Do Oscillation Angle, Frequency and Sliding Speed Determine the Life of a Spherical Plain Bearing?
- Q1-05 How Much Misalignment and Axial Load Can a Spherical Plain Bearing Take, and When Do You Need an Angular Contact Bearing?
- Q1-06 What Shaft and Housing Fits, Tolerances and Surface Finish Does a Spherical Plain Bearing Need?
- Q1-07 How Much Radial Internal Clearance Should a Spherical Plain Bearing Have, and How Do You Check It?
- Q1-08 What Grease, How Much and How Often for a Steel-on-Steel Spherical Plain Bearing, and How Do the Lubrication Holes and Grooves Work?
- Q1-09 How Do You Tell Why a Spherical Plain Bearing Failed: Wear, Galling, Fretting, Flaking or Liner Delamination?
- Q1-10 How Do You Install a Spherical Plain Bearing in a Housing Without Damaging It?
- Q1-11 Open or Sealed (ES or 2RS)? Which Seals and Materials Suit Dusty, Wet, Corrosive or Washdown Conditions?
- Q1-12 What Temperature Limits Apply to Steel-on-Steel and PTFE-Lined Spherical Plain Bearings?
- Q1-13 What Causes a Spherical Plain Bearing to Squeak, Stick, Bind or Show Stick-Slip, and How Do You Fix It?
- Q1-14 When Should a Spherical Plain Bearing Be Replaced: Measuring Play, Inspection and Wear Limits?
K03
Hydraulic Cylinder Rod Ends
Sizing rod ends and rod eyes for cylinders: push and pull force, pins, side loads, safety factors and installation.
15 articles
- Q1-02 What Types of Rod Ends and Rod Eyes Are Used on Hydraulic Cylinders, and How Do They Differ?
- Q1-03 Plain Rod Eye or Spherical Rod End on a Hydraulic Cylinder: Which Should You Use?
- Q1-04 Which Loads Does Each Hydraulic Cylinder Mounting Style Put on the Rod End?
- Q1-06 How Do You Size a Rod End for a Hydraulic Cylinder for Push and Pull Force, Shock Loads and Safety Factor?
- Q1-07 What Do the Static and Dynamic Load Ratings on a Rod End Mean?
- Q1-09 How Much Angular Misalignment Can a Spherical Rod End Take on a Cylinder?
- Q1-10 How Do Spherical Rod Ends Prevent Side Loading on a Hydraulic Cylinder, and Can a Worn Rod End Damage It?
- Q1-11 How Do You Identify and Measure a Hydraulic Cylinder Rod End for Replacement?
- Q1-12 How Do You Secure a Rod End on a Hydraulic Piston Rod and Stop the Thread Loosening or Galling?
- Q1-14 How Do You Choose the Pin for a Rod Eye on a Hydraulic Cylinder: Diameter, Material, Fit and Retention?
- Q1-22 Why Do Spherical Rod End Bearings Wear, Develop Play or Fail on Hydraulic Cylinders, and How Do You Inspect Them?
- Q1-24 Should You Replace Only the Spherical Bearing or the Whole Rod Eye on a Hydraulic Cylinder?
- Q1-27 How Is a Weld-On Rod Eye Attached and Inspected, and How Do Weld Failures Show Up?
- Q1-28 How Does Rod Eye Mounting Affect Hydraulic Cylinder Buckling and Column Strength?
- Q1-29 Which Standards Apply to Rod Ends and Rod Eyes? ISO 12240-4, DIN 648, ISO 6982, ISO 8132 and ISO 8133
K04
Small Ball Joints & Angle Joints
Compact ball joints and angle joints: pull-off force, tilt, threads, locking and selection against rod ends.
10 articles
- Q1-02 What Do the Letters C, CS, B and BS Mean on an Angle Joint, and When Do You Need a Safety Clip?
- Q1-04 How Does a Quick-Release Ball Joint Work, and When Is It Better Than a Standard Angle Joint?
- Q1-05 How Much Pull-Off Force Does a Ball Socket Hold, and How Do You Stop a Ball Joint from Coming Apart?
- Q1-07 How Do You Size a Small Ball Joint for an Actuator or Air Cylinder Linkage?
- Q1-09 How Much Can a Small Ball Joint Tilt, and How Do You Set Up a Linkage So It Does Not Bind?
- Q1-11 Steel, Stainless, Zinc-Plated or Plastic: Which Material Suits a Small Ball Joint?
- Q1-16 How Do You Fit and Remove a DIN 71805 Ball Socket Without Damaging the Spring Clip?
- Q1-18 How Do You Set the Length of a Ball Joint Linkage Rod, and Which Thread Size and Hand Should You Choose?
- Q1-23 How Do You Connect an Angle Joint to a Cylinder Rod, Threaded Rod or Bracket, and How Deep Should the Thread Go?
- Q1-26 Ball Joint or Rod End: Which Should You Use on a Pivoting Pneumatic Cylinder?
K05
Clevises & Yoke Ends
Clevis and yoke joints: sizing for a cylinder, pin shear and fit, retention, alignment and wear.
9 articles
- Q1-01 What Is a Clevis Rod End, Fork Head or Yoke End, and How Do the Types Differ?
- Q1-02 What Do DIN 71752 and ISO 8140 Cover for Clevis Rod Ends, and Which Dimensions Should You Check When You Order?
- Q1-03 When Should You Use a Clevis Instead of a Spherical Rod End or Rod Eye, and How Much Misalignment Can a Clevis Take?
- Q1-04 How Do You Choose a Clevis Size and Thread for a Cylinder, Set How Far It Screws On, and Lock It?
- Q1-05 What Limits the Load of a Clevis Joint, and How Do You Check Pin Shear?
- Q1-06 What Pin Diameter, Length, Fit and Hardness Should a Clevis Pin Have?
- Q1-07 Which Pin Retention Method Should You Use for a Clevis: Clip, Split Pin, Circlip or Locking Pin?
- Q1-09 Which Clevis Material and Finish Suits Wet, Corrosive or Washdown Service, and How Do You Avoid Galvanic Corrosion?
- Q1-12 Why Does a Cylinder Clevis Wear, Rattle or Crack at the Pin, and When Should the Fork Head, Pin or Bracket Be Replaced?
K06
Linkage Rods & Turnbuckles
Adjustable linkage rods, turnbuckles and jack screws: length, thread engagement, locking and materials.
12 articles
- Q1-01 Turnbuckle, Jack Screw, Adjustable Linkage Rod or Push-Pull Rod: What Is the Difference?
- Q1-02 How Do You Size an Adjustable Linkage Rod or Turnbuckle for Tension and Compression Loads?
- Q1-03 How Long Can a Push-Pull Rod Be Before It Buckles, and What Rod Diameter Do You Need?
- Q1-04 How Do You Calculate the Centre-to-Centre Length, Adjustment Range and Travel per Turn of an Adjustable Linkage Rod?
- Q1-05 Why Does an Adjustable Linkage Change Length Under Vibration, and Which Locking Method Works?
- Q1-06 Which End Fitting Suits an Adjustable Linkage Rod: Clevis, Rod End, Ball Joint or Eye End?
- Q1-07 Which Thread Size, Pitch, Class and Hand Should You Specify on a Linkage Rod, Turnbuckle or Jack Screw?
- Q1-08 Which Material and Coating Should You Choose for a Linkage Rod or Adjuster in Corrosive or Washdown Service?
- Q1-09 Why Do Turnbuckle and Jack Screw Threads Seize or Gall, and How Do You Free Them and Prevent It?
- Q1-10 How Do You Install and Align a Push-Pull Rod to Avoid Binding and Side Loading?
- Q1-11 How Do You Find and Reduce Backlash or Lost Motion in an Adjustable Linkage?
- Q1-12 How Often Should Linkage Rods, Turnbuckles and Jack Screws Be Inspected and Lubricated, and When Do They Need Replacing?
K07
Tube Adapters & Tubing
Tube adapters, weld-in fittings and tubing for link and frame members: joint failure, diameter and wall choice.
5 articles
- Q1-01 How Should a Rod End or Clevis Be Attached to a Tube in a Machine Linkage: Weld-In Adapter, Pinned or Bolted Insert, or Threaded-In Insert?
- Q1-02 How Do I Size a Tube Adapter to a Real Tube: Inside-Diameter Tolerance, Weld Seam, Seating Shoulder, Thread Size Limits and Which Tube Standard Controls the Fit?
- Q1-04 Where Does a Tube-Adapter Joint Fail First: Rod-End Thread, Adapter Thread, Weld or Tube, and How Do I Check Each Under Tension, Compression and Cyclic Load?
- Q1-08 A Welded-In Tube Adapter Is Cracked, Loose or Has a Stripped Thread: Re-Tap, Insert, Cut Out and Replace, or Scrap the Link?
- Q1-10 How Do I Choose Tube Diameter and Wall Thickness for a Push-Pull Link or Frame Member: Buckling, Bending and Torsion, and How Much Do the Adapter Ends Change the Answer?
K08
Polymer Bushings & Plain Bearings
Plastic and polymer bushings: material choice, clearance and heat, press fit, wear, dust and failure diagnosis.
13 articles
- Q1-01 How Do You Choose Between Acetal (Delrin), UHMW, Nylon and Polyurethane Bushings for an Industrial Machine?
- Q1-02 How Do You Calculate the PV Limit and Load Capacity of a Plastic Plain Bearing?
- Q1-03 What Running Clearance Should a Plastic Bushing Have, and Why Does Heat Make a Pressed-In Bushing Tighter, Not Looser?
- Q1-04 How Do You Press-Fit and Retain a Plastic Bushing Without Cracking It, and What Interference Does It Need?
- Q1-05 What Shaft Material, Hardness and Surface Finish Should You Use With Plastic Plain Bearings?
- Q1-06 Do Plastic Bushings Need Lubrication, or Can They Run Dry, and What Lubricant Is Compatible?
- Q1-07 Which Polymer Suits Washdown, Water and Chemical Exposure, and What Do Caustic Cleaners and Moisture Do to It?
- Q1-08 What Compliance Documents Should I Ask for When a Plastic Bushing Is Used in a Food Plant?
- Q1-09 Why Does a Plastic Bushing Wear, Seize, Squeak, Swell, Crack or Walk Out of Its Housing?
- Q1-10 How Do I Measure Wear on a Plastic Bushing, and When Should I Replace or Take It Out of Service?
- Q1-12 When Should I Use a Plastic Bushing Instead of a Bronze or Steel One, and What Changes If I Swap?
- Q1-13 Sleeve, Flanged, Split or Thrust Washer: Which Plastic Bushing Form Do I Need, How Long and Thick Should It Be, and How Do I Avoid Edge Loading?
- Q1-16 What Is the Maximum Operating Temperature of a Plastic Bushing, and What Happens as It Heats Up?
K09
Weld-on Ball Joints & Pivots
Weld-on ball joints and three-point hitch pivots: sizing, alignment, welding practice and replacement.
7 articles
- Q1-01 What Is the Difference Between a Weld-On Ball Joint, a Weld-On Ball Socket and a Weld-On Ball End, and What Do Shouldered and Non-Shouldered Mean?
- Q1-02 How Do You Choose a Three-Point Hitch Ball and Pin for the Implement Category (Category 0 to 4)?
- Q1-03 How Do You Size a Weld-On Ball Joint for Working Load, Shock and Cyclic Loads, and Combined Radial and Axial Loads?
- Q1-04 What Should You Know Before Welding a Ball Socket In: Material, Heat, Distortion and Alignment?
- Q1-06 Why Do Three-Point Hitch and Implement Pivot Ball Sockets Wear Loose, and How Do You Check the Play?
- Q1-07 How Do I Inspect the Welds Around a Ball Socket for Fatigue Cracks, and Can It Be Repaired?
- Q1-08 How Do I Replace a Worn Lift-Arm Ball Socket: Measure the Old One, Choose a Weld-On End, and Fit It Square?
K11
Rod End Accessories
Spacers, jam nuts and studs: what each does, how long it should be, locking and single-shear stud loading.
3 articles
- Q1-01 What Does a Plain, Cone or High-Misalignment Spacer Do, How Long Should It Be, and How Much Extra Tilt Does It Really Give?
- Q1-05 What Is the Difference Between a Jam Nut, a Regular Hex Nut and a Lock Nut, and Which One Should Lock a Rod End Thread?
- Q1-07 When Should a Rod End Be Mounted on a Stud Instead of a Through-Bolt, and How Do You Check the Stud for Bending at the Shoulder, Thread Engagement and Locking?
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1 article
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