IKO NAST25ZZ Separable Roller Follower, 25 mm bore, 52 mm OD, Shield, Cylindrical

This page covers 12 IKO NAST Series separable roller followers (track rollers) with inner ring (NAST8ZZ to NAST50ZZ, 8 to 50 mm bore): needle rollers in a cage, shield type construction and a cylindrical outer ring. Choose the size in the options above; each variant has its own dimensions and ratings in the Model Details.

The NAST series is the separable roller follower with inner ring: the outer ring, inner ring and needle roller cage can be separated from one another, which makes handling easy, and oil lubrication is easy, so it suits high speed rotations. A roller follower (track roller) is a bearing designed for outer ring rotation, with rollers inside a thick-walled outer ring. The outer ring runs directly on the mating cam guide surface, and roller followers are widely used in cam mechanisms and in linear motions of conveying equipment.

In the part number, ZZ is the shield type and ZZUU the sealed type, and R marks the crowned outer ring (no R is cylindrical). Every model on this page is shield type with a cylindrical outer ring.

Where this product is used

• Cam mechanisms, with the outer ring running directly on the cam guide surface
• Linear motions of conveying equipment
• Follower and track roller positions on a shaft

Features

• Separable roller follower with inner ring: outer ring, inner ring and needle roller cage can be separated, which makes handling easy
• Needle rollers in a cage: a small coefficient of friction and suited to high speed rotations
• Shield type: narrow clearances between the side plates and the outer ring form labyrinths
• Cylindrical outer ring: a large contact area on the mating guide surface, suited to large loads or a low hardness guide surface
• Basic dynamic load rating C 5,650 to 38,900 N and static load rating C0 5,890 to 71,700 N (each size in the Model Details)
• Track capacity 4,490 to 34,000 N on a 40 HRC mating surface

Key specifications

Available sizes

C is the basic dynamic load rating and C0 the basic static load rating; a is the mating seating dimension.

Selecting the right option

Pick the outside diameter (D, in mm) in the options above: the bore (shaft diameter), widths and ratings follow from the model number shown in the Model Details. Match the bore to the shaft you will fit.

This page is the cylindrical outer ring type. A cylindrical ring has a large contact area with the mating guide surface and suits applications where the applied load is large or the guide surface hardness is low.

Every model here has a cage, which gives a small coefficient of friction and suits high speed rotations.

Fitting and use

For the shield type, match the side surface correctly to the mating seating surface given by dimension a in the Model Details and fix it. The mounting part should make even contact with the entire side plate surface: uneven contact may increase rotational torque and shorten the service life.

Keep the oil hole of the inner ring out of the loading zone, which can lead to a short bearing life.

Recommended shaft tolerance for the metric series is g6 or h6.

Lubrication: the models on this page are not prepacked with grease, so supply grease or oil through the oil hole of the inner ring before use, because running without lubrication can wear the rolling contact surfaces.

Track capacity is the load that can be applied continuously on a steel cam guide surface of 40 HRC without deforming or indenting it.

Related products

Other IKO NAST series pages (other outer ring, rolling element, seal or material types): NAST series separable roller followers, with cage, sealed (ZZUU), cylindrical, 6 to 50 mm bore and NAST series separable roller followers, with cage, sealed (ZZUU), crowned, 6 to 50 mm bore. Related roller followers: NART series roller followers, with cage, sealed, crowned, 5 to 50 mm bore and NURT series cylindrical roller followers, full complement, shield type, cylindrical, 15 to 50 mm bore.