Mechanical Design Data and Machine-Element Reference: Pulley Groove Geometry

Pulley Groove Geometry — Key Dimensions

flowchart LR
    A[Belt Section Identified] --> B[Determine PCD Range]
    B --> C{PCD ≤ Threshold?}
    C -->|Yes| D["Single Groove Angle: 34°"]
    C -->|No| E["Dual Groove Angle: 38°"]
    D --> F[Apply Standard Groove Dimensions]
    E --> F
    F --> G["Key Dimensions:
    A' = Groove Angle
    D = Groove Depth
    e = Groove Pitch
    l = Belt Seat Width
    b = Tolerance Band
    lp = Datum Length
    W = Top Width
    R = Nominal Radius"]

Key Terms Glossary

• Wedge Belt: A V-shaped belt with a trapezoidal cross-section that wedges into the pulley groove for friction-based power transmission
• Narrow-Section Wedge Belt: An optimised V-belt profile (SPB, SPC) with a higher power-to-width ratio compared to classical sections
• CRE Belt: A classical/conventional wedge belt cross-section (SPZ, SPA, SPB) — smaller and less power-dense than narrow-section equivalents
• Pitch Diameter (PCD): The effective working diameter of the pulley at the belt's neutral axis — used for all speed and power calculations
• Outside Diameter (O): The overall outer diameter of the pulley including the groove lands
• Taper Lock Bush: A split, tapered sleeve that locks a pulley concentrically onto a shaft using clamping bolts — allows keyless or keyed mounting
• Bush Number: A standardised code identifying the taper lock bush dimensions, bore range, and bolt pattern
• Speed Ratio: The ratio of driven pulley PCD to driver pulley PCD — determines the torque multiplication and speed reduction
• Belt Speed (m/s): The linear speed of the belt, calculated as π × PCD × RPM / 60,000 — critical for power rating selection and centrifugal load limits
• Groove Angle (A'): The included angle of the V-groove — typically 34° for smaller pulleys and 38° for larger pulleys within the same belt section
• Groove Pitch (e): The centre-to-centre distance between adjacent grooves on a multi-groove pulley
• Face Width (F): The total width across the pulley face, encompassing all grooves and edge margins
• Non-Preferred Pulley Size: A catalogue entry marked with an asterisk (*) indicating it is not the standard/recommended size — may have longer lead times or limited availability
• Type 6NR: A pulley construction variant using a non-standard retaining method — typically found in older or transitional designs

Quick Revision

• SPB wedge belts cover PCDs from 140–315 mm and can transmit up to approximately 31 kW per belt — used for medium-to-heavy industrial drives
• SPC wedge belts cover PCDs from 224–560 mm and can transmit up to approximately 60 kW per belt — the largest standard narrow-section profile
• CRE belts (SPZ, SPA, SPB) are smaller classical profiles suited for light to medium duty — max power per belt ranges from ~5 kW (SPZ) to ~13 kW (SPB CRE)
• Belt speed must not exceed 40 m/s — for speeds between 30–40 m/s, confirm pulley suitability with the manufacturer
• Additional power is added per belt when the speed ratio exceeds 1.0 — this accounts for improved belt wrap on the smaller pulley
• Taper lock pulleys use a split taper bush for shaft mounting — bush number determines max bore and shaft compatibility
• Groove angles change with pulley PCD: 34° for smaller pulleys, 38° for larger pulleys within each belt section
• Minimum groove counts vary by belt section: SPZ/Z = 1, SPA/A = 1, SPB/B = 2, SPC/C = 3
• Pulley types progress from solid/plate construction at small diameters to spoked construction at large diameters for weight reduction
• Non-preferred sizes (marked with *) should be avoided in new designs — use standard catalogue entries for availability and cost efficiency
• Always verify: belt section → power rating → pulley PCD → number of grooves → bush size → bore compatibility → groove dimensions

SHAFTS, KEYS, BEARINGS & SEALS

Shafts, Keys, Circlips, Seals & Rolled Steel Sections

Overview

• This chapter covers the mechanical design of shafts — rotating members supported by bearings that transmit torque and power
• Topics include shaft load classification, failure modes, design approaches, stress formulas, load estimation methods, and design procedures for determining minimum shaft diameter
• Also covered: circlip and seal sizing (metric long-life series), and rolled steel section selection for beams and columns
• Key design philosophy: calculate equivalent torque and moment from combined loading, apply shock/fatigue factors, then determine shaft diameter using strength-of-materials formulas
• Two primary design approaches are presented — one based on endurance limit and another based on basic strength of materials with generous safety factors

Key Concepts

• Shaft: A rotating member supported by bearings that transmits torque and power
• Steady Loads: Torsional, bending, and axial loads that occur continuously during operation
• Shock Loads: Intermittent, sudden increases in load (e.g., initial engagement in rolling or pressing operations)
• Inertia Loads: Loads arising from acceleration or deceleration of the shaft and attached equipment
• Equivalent Torque (T_E): A combined measure incorporating both torque and bending moment — used to find shaft diameter from shear stress
• Equivalent Moment (M_E): A combined measure used to find shaft diameter from bending stress
• Shock/Fatigue Factors (K_T, K_M): Multipliers applied to steady torque and moment to account for dynamic loading effects
• Stress Concentration: Localised increase in stress at geometric discontinuities such as keyways, shoulders, grooves, or holes
• Endurance Limit: The stress level below which a material can theoretically sustain an infinite number of load cycles without fatigue failure
• Drive Application Factor (f): A multiplier used to account for the difference between actual transverse shaft load and the simplified calculated value

Shaft Definition and Characteristics

• Definition: A rotating member supported by bearings that transmits torque and power
• Rotation may be continuous, intermittent, uni-directional, or reversing
• Shafts attached to wheels are often called axles
• Usually circular in cross-section — solid or hollow; sometimes square for specific applications
• Typically rigid; flexible shafts (cables) exist for specialised applications but are not covered here
• Usually long relative to diameter
• Commonly made from steel or other metals; non-metallic shafts are sometimes used
• Torque and power are transmitted from an input location (e.g., a prime mover) to an output location (e.g., a driven load)
• Input may come from a motor, engine, or intermediate shaft via gears, belts, or chains
• Output may be transmitted directly to a load or via power transmission devices

Shaft Loads and Stresses

Steady Loads

• Primary design loads that occur relatively continuously during operation
• Three types act on shafts, often simultaneously:

Shock Loads

• Intermittent in nature, causing sudden increases in load
• Common in rolling mills, punching/cropping presses, and similar applications
• Shafts must be designed to withstand shock loads even if they occur only momentarily
• Load-limiting devices (shear pins, overload protection) are often fitted to protect the shaft

Inertia Loads

• Occur during acceleration or deceleration (speed changes)
• Magnitude depends on:
  • Rate of acceleration/deceleration (magnitude)
  • Mass moment of inertia of the shaft and coupled equipment/transmission devices
• Typically occur during start-up and shut-down phases
• For electric motors:
  • Soft-start (current-limiting device fitted): starting torque ≤ 1.5–2× rated load torque
  • Hard-start (no current limiter): starting torque can be 3–5× rated load torque

Shaft Failure Modes

Failure Due to Excessive Load

• Occurs when shaft stress exceeds the yield stress
• Relatively rare due to load-limiting devices (shear pins, overload protection) in most systems
• If overload causes yielding without fracture, the shaft may remain serviceable
• Design goal: prevent stress from exceeding yield stress; permanent deformation = failure

Failure Due to Fatigue

• Most common failure mode for shafts with high revolution counts
• Can occur even when stresses are well below yield point
• Most likely when loads continually fluctuate, especially with stress reversal
• Two mechanisms of stress reversal:
  • Change in load direction: Most common for torsional stress reversal (e.g., vehicle transmission shafts reversing between drive and braking)
  • Rotation of the shaft: Most common for bending stress reversal (e.g., a horizontal shaft with a downward load — top and bottom alternate between tension and compression each half-revolution)

Shaft Design Approaches

Approach 1: Endurance-Based

• Calculate peak loads (including inertia and shock) and stress concentrations as accurately as possible
• Allowable shaft stresses include an allowance for shaft size — larger diameter = lower allowable stress
• For shafts with many revolutions: design to prevent fatigue failure using the endurance limit
• Endurance limit is determined from standardised fatigue tests on polished specimens (typically 8–10 mm diameter)
• A small factor of safety (typically ~1.2) is applied, based on the endurance limit
• Based on relevant national rotating shaft design standards

Approach 2: Strength-of-Materials-Based (Recommended)

• Calculate the maximum design load likely under operating conditions
• Apply shock/fatigue factors and a relatively generous factor of safety
• Account for inertia loads and non-uniformity of material properties
• Use basic strength of materials formulas to calculate shaft stresses or diameter
• More fundamental approach; provides better understanding of stresses involved
• Avoids complex formulas with unstated assumptions
• Based on recognised engineering code methodology

Core Stress Formulas

Combined Shear Stress (Formula 1)

$$f_s = \frac{16 \, T_E}{\pi \, d^3}$$

• Used to find shaft diameter from torsional shear stress

Combined Axial Stress (Formula 2)

$$f_s = \frac{32 \, T_E}{\pi \, d^3}$$

• Used to find shaft diameter from bending (axial) stress

Equivalent Torque (Formula 3)

$$T_E = \sqrt{T^2 + M^2}$$

• Combines torque (T) and bending moment (M) into a single equivalent value

Equivalent Moment (Formula 4)

$$M_E = 0.5 \, (T_E + M)$$

• Used for bending stress calculations

Design Torque and Moment (with shock/fatigue factors)

$$T = K_T \cdot T_S \qquad M = K_M \cdot M_S$$

• Where T_S and M_S are the steady torque and moment
• K_T = shock/fatigue factor in torsion
• K_M = shock/fatigue factor in bending

Shock/Fatigue Factor Values

• K_M = 1.5 minimum even for static loads — accounts for bending stress reversal due to shaft rotation (constant load direction and magnitude)
• These factors apply to bending, torsion, or combined bending and torsion (the most common loading)
• For significant axial loads, more complex formulas (e.g., from relevant engineering codes) should be used, including column effects for compression

Allowable Stresses and Factors of Safety

• For steel shafts using the fundamental design approach:
  • Bending (tension or compression): the smaller of 40% f_y or 24% f_ult
  • Torsion (shear): the smaller of 30% f_y or 18% f_ult
• Where:
  • f_y = yield strength
  • f_ult = ultimate tensile strength
• The allowable shear stress is based on the assumption that shear strength ≈ 75% of tensile strength

Stress Concentration at Keyways

• Keyways are one of the most important sources of stress concentration in shafts
• Located where gears, sprockets, or pulleys are fitted — usually the most highly stressed locations
• Design rule of thumb: allowable stresses with a keyway are 75% of allowable stresses without the keyway
• For other stress concentrations (steps, holes), consult relevant engineering design standards and handbooks

Estimating Shaft Loads

1. Weight (Gravitational Load)

• Applies when a heavy pulley, flywheel, or similar component is mounted on a non-vertical shaft
• Causes a transverse bending force:

$$F = m \cdot g$$

• Assumed: shaft supported by low-friction bearings (frictional torque negligible)

2. Chain Drive

• Chain tension creates a transverse force on the shaft at the sprocket
• Force at sprocket: $F = T_2 + T_1$ — (Formula 5) — tight side + slack side tension
• Torque at sprocket: $T = (T_2 - T_1) \cdot d/2$ — (Formula 6)
• Where d = pitch circle diameter (PCD) of the sprocket (in metres)
• When transmitting power, slack side tension is usually negligible → T_1 ≈ 0

3. Belt Drive (Vee or Wedge)

• Same approach as chain drive, but slack side tension is NOT zero (friction-dependent)
• Formulas 5 and 6 apply for belt drives as well
• For parallel belts: F = T_2 + T_1 (correct); for non-parallel belts: use vector sum (but scalar sum errs on the safe side)
• When both T_2 and T_1 are unknown, use one of three methods:

Method (a): Assume Slack Side Tension

• Based on mid-load power at 1000 rev/min, tension ratio 12:1, smallest recommended PCD for belt size

Method (b): Assume Belt Tension Ratio

• Based on 90% of tension ratio at slip point on smaller pulley; wedge angle 38°, friction coefficient 0.3, centre distance = sum of pulley PCDs; centrifugal effects excluded
• Linear interpolation can be used for intermediate values

Method (c): Assume a Drive Application Factor

• If slack side tension were zero: $F = 2T/d$
• Actual force is greater because T_1 ≠ 0 → apply factor f:

$$F = \frac{2 \, f \, T}{d}$$

• For vee or wedge belt drives, f is typically taken as 1.5
• For chain drives: if T_1 = 0, then f = 1
• Note: f = 1.5 gives a result ~20% higher than other methods; f = 1.25 gives closer correlation

4. Gear Drive

• Force on the shaft = resultant transverse force at the gear tooth contact point
• Three force components:
  • F_t (tangential force): produces the torque; $F_t = 2T/d$ — (Formula 8)
  • F_s (separating/radial force): keeps gears in mesh; acts through gear centrelines
  • F (resultant transverse force): vector sum of F_t and F_s
• Pressure angle (θ): angle between F and F_t — typically 20° unless stated otherwise

Spur Gear Formulas

$$F_s = F_t \cdot \tan\theta \qquad \text{(Formula 9)}$$

$$F = \sqrt{F_t^2 + F_s^2} \qquad \text{(Formula 10)}$$

Helical Gear Formulas

• Helical gears have teeth cut at an angle (helix angle α) to the shaft axis
• Stronger and quieter than spur gears, but produce an additional axial force

$$F_s = \frac{F_t \cdot \tan\theta}{\cos\alpha} \qquad \text{(Formula 11 — separating force)}$$

$$F_a = F_t \cdot \tan\alpha \qquad \text{(Formula 12 — axial force)}$$

• The resultant transverse force is still $F = \sqrt{F_t^2 + F_s^2}$

Design Procedure

1. Estimate all loads acting on the shaft (weight, drive forces, gear forces, etc.)
2. Draw torque, shear force, and bending moment diagrams
   • Shear force diagram is optional but useful to draw before the bending moment diagram
3. Identify the critical location — position of maximum combined stress (usually where torque and bending moment are both at maximum, typically at gear/sprocket/pulley locations)
4. Determine the design torque and moment by applying shock/fatigue factors (K_T, K_M)
5. Calculate equivalent torque (T_E) and equivalent moment (M_E)
6. Calculate allowable stresses (with keyway reduction if applicable)
7. Determine minimum shaft diameter using Formulas 1 and 2
8. Select the closest standard shaft size (round up)

Single-Plane vs Multi-Plane Bending

• Single-plane: all resultant transverse forces act in the same plane → one bending moment diagram needed
• Multi-plane: transverse forces act in different planes (e.g., horizontal and vertical) → draw bending moment diagrams for each plane, then combine:

$$M = \sqrt{M_v^2 + M_h^2} \qquad \text{(Formula 13 — resultant bending moment)}$$

• Where M_v = vertical plane moment, M_h = horizontal plane moment

Design Notes

• Treatment excludes significant axial loads — in most shafts, direct axial stress is small relative to bending and torsional stresses
• Examples use single-diameter shafts; the same principles apply to stepped shafts — each step diameter is determined from the maximum stress at that section
• For stepped shafts: apply a stress-concentration factor at each step (depends on ratio of diameters and internal radius)

Rolled Steel Sections

Overview

• Hot rolled sections are available in standard profiles: universal beams, universal columns, parallel flange channels, equal/unequal angles, and merchant bar (rounds, squares, flats)
• Hot rolled sections have a commercial finish — not suitable for rotating shafts (use bright steel for shafts)
• Available in several grades:

Beam Selection Procedure

1. Determine the maximum bending moment (M) from loading and span
2. Calculate the allowable bending stress using the design factor:
   • e.g., for a design factor of 2 on yield: $f_b = f_y / 2$
3. Calculate the required section modulus: $Z = M / f_b$
4. Select the smallest standard section with Z ≥ required Z from beam tables
5. Check self-weight: recalculate reactions, moment, and Z including beam self-weight
6. Verify the selected section is still adequate

Column Selection Procedure

1. Determine the effective length (L_e) based on end conditions:
   • Both ends pinned: L_e = L
   • One fixed, one free (cantilever): L_e = 2L
   • One fixed, one pinned: L_e = 0.7L
   • Both ends fixed: L_e = 0.5L
2. Calculate the design critical load = applied load × design factor
3. Calculate the limiting slenderness ratio:

$$\left(\frac{L_e}{r}\right)_{lim} = \sqrt{\frac{2\pi^2 E}{f_y}}$$

4. Select a trial section from column tables; use the smaller radius of gyration (r_y) for buckling analysis
5. Calculate actual $L_e/r$ and compare with limiting value
6. If $L_e/r$ > limiting value → slender column → use Euler formula:

$$F_{cr} = \frac{\pi^2 E A}{(L_e/r)^2}$$

7. Check that $F_{cr}$ ≥ design critical load; iterate if necessary

Shaft Design Approaches Compared

Shaft Failure Modes Compared

Belt Load Estimation Methods Compared

Spur vs Helical Gear Forces

Shaft Design Process

flowchart TD
    A[Identify All Shaft Loads] --> B[Estimate Load Magnitudes]
    B --> C{Load Type?}
    C -->|Weight| D[F = mg]
    C -->|Chain Drive| E["F = T₂ + T₁ <br/> T = (T₂ - T₁) · d/2"]
    C -->|Belt Drive| F[Use Method a, b, or c]
    C -->|Gear Drive| G["F_t = 2T/d <br/> F_s = F_t · tan θ <br/> F = √(F_t² + F_s²)"]
    D --> H[Draw Shear Force & Bending Moment Diagrams]
    E --> H
    F --> H
    G --> H
    H --> I[Identify Critical Location]
    I --> J["Apply Shock/Fatigue Factors <br/> T = K_T · T_S <br/> M = K_M · M_S"]
    J --> K["Calculate T_E = √(T² + M²) <br/> M_E = 0.5(T_E + M)"]
    K --> L["Calculate Allowable Stresses <br/> Bending: min(0.4·f_y, 0.24·f_ult) <br/> Shear: min(0.3·f_y, 0.18·f_ult)"]
    L --> M{Keyway Present?}
    M -->|Yes| N[Multiply Allowable Stresses × 0.75]
    M -->|No| O[Use Full Allowable Stresses]
    N --> P["Solve for d from: <br/> f_s = 16·T_E / (π·d³) <br/> f = 32·M_E / (π·d³)"]
    O --> P
    P --> Q[Select Larger Diameter <br/> Round Up to Standard Size]

Shaft Load Classification

flowchart LR
    A[Shaft Loads] --> B[Steady Loads]
    A --> C[Shock Loads]
    A --> D[Inertia Loads]
    B --> B1[Torsional]
    B --> B2[Bending]
    B --> B3[Axial]
    C --> C1[Intermittent <br/> Sudden Increase]
    D --> D1[Start-Up / Shut-Down]
    D1 --> D2["Soft-Start: 1.5–2× rated"]
    D1 --> D3["Hard-Start: 3–5× rated"]

Shaft Failure Decision Tree

flowchart TD
    A[Shaft Under Load] --> B{Stress > Yield?}
    B -->|Yes| C[Excessive Load Failure]
    C --> C1[Permanent Deformation]
    C1 --> C2{Shaft Broken?}
    C2 -->|No| C3[May Still Be Serviceable]
    C2 -->|Yes| C4[Replace Shaft]
    B -->|No| D{Cyclic Stress Reversal?}
    D -->|Yes| E{Stress > Endurance Limit?}
    E -->|Yes| F[Fatigue Failure Over Time]
    E -->|No| G[Infinite Life — No Failure]
    D -->|No| G

Multi-Plane Bending Resolution

flowchart TD
    A[Forces on Shaft in Multiple Planes] --> B[Resolve into Vertical & Horizontal Components]
    B --> C[Draw Vertical Plane BM Diagram → M_v]
    B --> D[Draw Horizontal Plane BM Diagram → M_h]
    C --> E["Resultant: M = √(M_v² + M_h²)"]
    D --> E
    E --> F[Proceed with Design Using Resultant M]

Beam Selection Flowchart

flowchart TD
    A[Given: Span, Loading, Grade, Design Factor] --> B[Calculate Max Bending Moment M]
    B --> C["Allowable Stress f_b = f_y / Design Factor"]
    C --> D["Required Z = M / f_b"]
    D --> E[Select Smallest Section with Z ≥ Required]
    E --> F[Check Self-Weight]
    F --> G{Z Still Adequate?}
    G -->|Yes| H[Section Confirmed]
    G -->|No| I[Select Next Larger Section]
    I --> F

Key Terms Glossary

Shaft Design — Must-Know Formulas

• Combined shear stress: $f_s = 16 T_E / (\pi d^3)$
• Combined bending stress: $f = 32 M_E / (\pi d^3)$
• Equivalent torque: $T_E = \sqrt{T^2 + M^2}$
• Equivalent moment: $M_E = 0.5(T_E + M)$
• Design torque: $T = K_T \cdot T_S$
• Design moment: $M = K_M \cdot M_S$

Allowable Stresses (Steel Shafts)

• Bending: smaller of 40% f_y or 24% f_ult
• Shear: smaller of 30% f_y or 18% f_ult
• With keyway: multiply both by 0.75

Shock/Fatigue Factors — Quick Reference

• Static/gradual: K_T = 1.0, K_M = 1.5
• Sudden + minor shock: K_T = 1.0–1.5, K_M = 1.5–2.0
• Sudden + heavy shock: K_T = 1.5–3.0, K_M = 2.0–3.0

Shaft Load Formulas

• Weight: F = mg
• Chain/belt drive force: F = T_2 + T_1
• Chain/belt torque: T = (T_2 - T_1) · d/2
• Belt drive with factor: F = 2fT/d (f ≈ 1.5 for belt drives)
• Gear tangential force: F_t = 2T/d
• Spur gear separating force: F_s = F_t · tan θ
• Helical gear separating force: F_s = F_t · tan θ / cos α
• Helical gear axial force: F_a = F_t · tan α
• Resultant gear force: F = √(F_t² + F_s²)
• Multi-plane resultant moment: M = √(M_v² + M_h²)

Column Design — Quick Reference

• Limiting slenderness ratio: $(L_e/r)_{lim} = \sqrt{2\pi^2 E / f_y}$
• Euler critical load: $F_{cr} = \pi^2 E A / (L_e/r)^2$
• Use the smaller radius of gyration for buckling checks
• If $L_e/r$ > limiting value → slender → Euler applies

Key Design Reminders

• K_M is never less than 1.5 (even for static loads) due to bending stress reversal from rotation
• Fatigue is the most common shaft failure mode — not overload
• Soft-start motors: 1.5–2× rated torque; hard-start: 3–5× rated torque
• Shaft diameter is determined by the more critical of shear stress and bending stress — check both
• For stepped shafts: apply stress concentration factors at each step
• Hot rolled sections → not for rotating shafts; use bright steel instead

Rolling Element Bearings

Overview

• Topic: Rolling element bearing selection, life calculation, and design methodology
• Scope: Covers bearing types, load rating systems, life prediction methods (basic, adjusted, and advanced), bearing selection procedures for multiple bearing categories, and supporting reference data
• Core Principle: Bearing life is a statistical estimate influenced by load, lubrication, cleanliness, and material — the more factors accounted for, the more accurate the prediction
• Key Takeaway: Three progressively refined methods exist for calculating bearing life, each incorporating additional real-world factors beyond basic load capacity

Dynamic Load Rating and Bearing Life

• Basic Dynamic Load Rating (C): The constant radial load under which a group of identical bearings will achieve a basic rating life of 1 million revolutions
• L₁₀ Life: The life that 90% of a sufficiently large group of identical bearings can be expected to attain or exceed under given operating loads
• The average life of a bearing is approximately 5 times the L₁₀ life
• L₁₀ life is expressed in millions of revolutions

Three Methods for Determining Bearing Life

• Method 1 — Basic L₁₀ Life: Accounts only for the loads on the bearing; simplest and most conservative
• Method 2 — Adjusted Rating Life (Lna): Extends Method 1 by incorporating reliability, material type, and lubricant viscosity
• Method 3 — New Life Theory (Lnaa): Further extends Method 2 by adding the concept of a fatigue load limit and contamination factor, enabling infinite life prediction under ideal conditions

Factors Affecting Bearing Life

• Steel type: Standard bearing steels meet international specifications; premium steels can exceed standard life properties
• Lubrication: Encompasses lubricant type (oil/grease), additives, viscosity, temperature, circulation method, and change intervals
• Cleanliness: Encompasses environmental contaminants, particulate ingress, water contamination, lubricant filtration, and sealing method

Bearing Types Overview

• 37 common types of rolling element bearings exist, categorised into radial and thrust families
• Selection depends on factors such as: load direction, shaft speed, accuracy, noise, friction, self-alignment capability

Radial Bearings

• Deep groove ball bearings — Single row, double row, with shields or seals, with snap ring groove in outer ring
• Self-aligning ball bearings — Cylindrical or tapered bore, with seals, with extended inner ring
• Angular contact ball bearings — Single row, paired mounting, precision, double row, four-point contact
• Cylindrical roller bearings — Multiple sub-types (NJ, NJP, NNU, NN), single/double/four row, full complement
• Needle roller bearings — Drawn cup, open/closed ends, with flanges, with/without inner ring, with seals
• Spherical roller bearings — Cylindrical or tapered bore
• Taper roller bearings — Single row, four row, crossed

Thrust Bearings

• Thrust ball bearings — Single/double direction, with flat/spherical housing washers, with sealing rings
• Angular contact thrust ball bearings — Single/double direction
• Cylindrical roller thrust bearings
• Needle roller thrust bearings
• Spherical roller thrust bearings
• Taper roller thrust bearings — Single/double direction