PaperAge Magazine

Paper Mill Eliminates Downtime on Calendar Roll with High Speed, High Temperature Spherical Roller Bearings from NSK

A major paper mill saves $480,000 over a five-year period after replacing standard spherical bearings with NSK's TL (Tough and Long Life) Series of spherical roller bearings.

NSK - Spherical Roller Bearings - TL Series NSK’s TL Series of Spherical Roller Bearings are specifically designed for longer bearing life while operating under extremely high temperatures in paper machine dryer and calender applications.


Calender rolls are subject to heavy loads and high speeds which can rapidly cause fatigue in spherical roller bearings. High heat of the application causes expansion of the bearing inner ring leading to cracks, ultimately resulting in bearing failure.

Success Story

Key Facts

  • A major paper mill was experiencing multiple inner ring crack on their calendar roll bearings
  • Standard spherical bearing was being used without carburized inner rings
  • 12 failures annually
  • Excessive downtime and maintenance

Value Proposals

  • NSK investigated the failed competitor's bearings
  • Application review was conducted by NSK engineers
  • It was determined that the high heat in the application was causing the bearing's inner rings to crack


  • Replace standard spherical bearing with NSK TL Series spherical roller bearing

Product Features

  • Innovative chemical steel composition
  • Special heat treatment process
  • High strength inner and outer rings
  • Heat resistant to cracks
  • Greater resistance to hoop stress
  • Longer service life — more than twice that of conventional bearings operating under contaminated conditions
  • Greater dimensional stability under high temperatures (to 200O C).

Cost Savings Breakdown


Bearings: 12 @ $10,000

Downtime: 4 hrs @ $1,500/hr x 6




NSK Solution

Bearings: 6 @ $10,000

Downtime: Eliminated





  • Before NSK Solution: Total Costs: $156,000 x 5 years = $780,000
  • After NSK Solution: $60,000 x 5 years = $300,000

About NSK's TL Series of Spherical Roller Bearings

NSK Tough and Long Life (TL) Series of Spherical Roller Bearings are ideally designed for the high temperature and high speed conditions of paper machine dryer and calender applications. With an innovative steel composition and special heat-treatment that offers superior dimensional stability and resistance to inner ring fractures, TL Spherical Roller Bearings provide utmost performance reliability, bearing life, and critically important machine up-time.

To learn more about NSK and its line of bearings specifically designed for the paper industry, visit: