Which Pin Retention Method Should You Use for a Clevis: Clip, Split Pin, Circlip or Locking Pin?
Use a split (cotter) pin for a joint you rarely open, and a reusable clip such as an R-clip for one you open often. A circlip works where the pin has a groove for it. A bolt with a self-locking nut also works if the thread is outside the shear plane. Every method is a […]
Which Clevis Material and Finish Suits Wet, Corrosive or Washdown Service, and How Do You Avoid Galvanic Corrosion?
For ordinary dry service, galvanised or zinc-plated steel is the usual choice. For continuous water, salt or washdown, use stainless steel, and choose the grade for the chemicals. Where two different metals touch in the presence of water, one of them can corrode faster than it would alone. Keep the joint dry, keep the metals […]
What Do DIN 71752 and ISO 8140 Cover for Clevis Rod Ends, and Which Dimensions Should You Check When You Order?
DIN 71752 is a German standard for clevises (fork joints). ISO 8140 gives the mounting dimensions of rod-end clevises for pneumatic cylinders. Both fix geometry, meaning where the pin, the fork opening and the thread sit, so that parts fit. Neither gives a load rating you can design to, and material and finish are left […]
What Pin Diameter, Length, Fit and Hardness Should a Clevis Pin Have?
Take the diameter from the shear and bearing check for your load, make the pin a close but free fit in the holes, make it long enough to reach the retainer, and make the pin harder than the part you want to keep. Diameter and length alone do not specify a pin: retention, shear capacity […]
What Is a Clevis Rod End, Fork Head or Yoke End, and How Do the Types Differ?
A clevis rod end is a U-shaped fork with a cross-hole, screwed on the end of a rod. A pin passes through the fork and the part it joins, so the joint turns in one plane. “Fork head”, “rod clevis” and “yoke end” are names for the same family of part. The types differ in […]
How Do You Choose a Clevis Size and Thread for a Cylinder, Set How Far It Screws On, and Lock It?
Start from the cylinder, not the clevis. Read the thread on the end of the piston rod (diameter, pitch, length and hand) and choose a clevis whose thread matches it. Then match the clevis to the bracket: pin diameter, inside width of the fork and pin centre distance. Screw the clevis on far enough that […]
When Should You Use a Clevis Instead of a Spherical Rod End or Rod Eye, and How Much Misalignment Can a Clevis Take?
Use a clevis when the load and the swing stay in one plane and the mounting points are well aligned. It is simple, strong in shear and quick to assemble. Use a spherical rod end when the link moves in more than one plane or the mounting cannot be lined up exactly. A clevis takes […]
Why Does a Cylinder Clevis Wear, Rattle or Crack at the Pin, and When Should the Fork Head, Pin or Bracket Be Replaced?
Most pin-joint trouble starts as clearance. The pin, its bushing or the bore wears, the joint begins to rattle, and the play then turns a steady load into repeated hammering until a fork ear or the thread cracks. The usual causes are a pin that is too soft, too small or overloaded, grease that is […]
What Limits the Load of a Clevis Joint, and How Do You Check Pin Shear?
A clevis joint is only as strong as its weakest part, and there are four to look at: the pin (shear, bending and bearing pressure), the lugs and fork around the pin holes, the thread that joins the clevis to the rod, and the rod itself. For the pin, the average shear stress in double […]