Ball bearing unit data

Boundary dimensions in accordance with:
  • ISO 3228
    • FY .. U and FYTB .. M series
    • FY .. U series, except for the attachment bolt hole distance (J), total width (A), and the bearing position relative to the support surface
    • FYK and FYTBK series
    • PFT, PF and PFD series
  • JIS B 1559
    • FYJ, FYTJ and FYC series
  •  no standard (neither national nor international), but common in the marketplace
    • F4BC, F2BC and F3BBC series
    • F4BSS and F2BSS series
Bearing data
TolerancesTolerance for the total width T (fig. 1) of units, except for the SKF Food Line:
  • d ≤ 50 mm
    → ±0,5 mm
  • d > 50 mm
    → ±0,6 mm

The outside diameter of the bearing is matched to its seat in the housing so that the outer ring is prevented from turning, but is still able to compensate for misalignment.

For tolerances of the SKF Food Line units, contact the SKF application engineering service.

Bearing data
Radial internal clearanceBearing data

Cast iron

  • FY(J), FYT(J), FYTB and FYC series
    • grey cast iron EN-GJL-HB235 in accordance with EN 1561


  • FYK and FYTBK series
    • glass fibre reinforced PA6
    • "moulded in" steel coil reinforcement

Pressed steel

  • PFT, PF and PFD series
    • cold-rolled sheet steel, chromium6+ free zinc-coated

Composite for the SKF Food Line

  • F4BC, F2BC and F3BBC series
    • glass fibre reinforced PP

Stainless steel

  • F4BSS and F2BSS series
    • cast austenitic stainless steel (AISI 300 series)
Components and materials

Bearing data

For units with a back seal (designation suffix DFH), the permissible static initial misalignment of the bearing is 1°.

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