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Grooved pin

Grooved pins are cylindrical fasteners fitted with a series of longitudinal grooves, which cause the pin to flow (swell and upset) as it passes through the groove. Most often, we find 3 splines at 120°. 

Unlike a ground pin, a splined pin does not require a specific fit tolerance, because the elasticity of the splines matches the diameter of the hole in which it is inserted. The bulge diameter is slightly larger than the nominal diameter, ensuring a perfect fit and therefore optimized hold.

When the pin is pressed into the assembly hole, the splines are designed to partially close elastically under pressure, to achieve a perfect fit between the pin and the assembly material. The resultant high-strength elastic clamping ensures that the pin remains securely in place, even when subjected to violent vibrations.

They are often used in applications where a high holding force is required, such as in the powertrain of automotive applications.

Grooved pin iso 8739 to iso 8745 - Cylindrical pin

What is a fluted part?

A fluted part is one that has grooves all over its surface. The flutes are grooves that run parallel on the part.

Used in a wide range of industrial sectors, splined pins ensure the reliability and strength of their intended application.

Grooved parts have different functions: 

  • Solidarization: immobilizing one part in relation to another, since the splines create a rough surface that prevents any play between the parts by clinging to them.
  • Positioning: splines are also used to position one part in relation to another. They can be used to position a shaft in a housing.
  • Rotation: splines help create an axis of rotation within an assembly.
  • Securing the part: the splined part serves as a safety part in an assembly, preventing parts from coming loose from an assembly.

What is a spline pin?

A splined pin is a cylindrical cylindrical pin with grooves cut into its surface.

A splined pin can have 1, 2, 3 or 6 splines.

It's more common to find a splined pin with 3 splines at 120° to distribute forces evenly around the assembly. 

The splines provide stability for the pin and the housing into which it is inserted.

The splines close when the pin is inserted into its seat, offering a degree of stability to the pin and to the parts it loads. When the splines partially close, the pin creates an adjustment between the pin and the hole, making the clamping "elastic".

A splined pin has the same functions as a splined part, i.e. :

  • Solidarity
  • Positioning
  • Rotation
  • Securing parts.

How is an LGC spline pin made?

The LGC method for manufacturing a splined pin involves cutting a bar from the desired material to the required dimensions.

Once the bar has been cut, we submit the parts to one of our 30 splining machines, which have been custom-designed to optimize the quality of our splined parts.

The machine precisely splines the workpieces using two types of tools called "nails" and "rollers".

What are the different types of spline pin?

There are many different types of spline pins, each with its own special features:

  • The ISO 8739 splined pin: longitudinal splines along the entire length, non-through-going.
  • The ISO 8740 splined pin: progressive splines over half the length, non-through-going.
  • The ISO 8741 splined pin: progressive splines reversed over half the length, non-through hole.
  • The ISO 8742 splined pin: longitudinal splines running the full length of the pin.
  • The ISO 8743 splined pin: longitudinal splines along the entire length, opening with a tapered tip
  • The ISO 8744 splined pin: longitudinal splines running the full length of the pin, with a tapered tip.
  • The ISO 8745 splined pin: longitudinal splines running the full length of the pin, with a flat tip.

PS: Unbolted means that the pin protrudes from the parts it secures, making them easier to assemble and disassemble.

The particularity of these pins defines their characteristic as well as their specificity, but overall, grooved pins all have the same advantages.

The advantages of splined pins in general are as follows:

  • Ease of installation: the splines of a splined pin allow the part to fit into its housing without constraint, the advantage being that it can be inserted even if there is a slight difference in diameter.
  • Vibration absorption: splines have the advantage of reducing and distributing the vibration the part can receive.
  • Virtually non-existent risk of cracking and breakage: the splines ensure uniform stress distribution on the parts, which greatly reduces the risk of cracking and breakage.

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