Bearing housing bore: Roundness Tolerance IT6-IT7 grade

Component Specifications

Definition

A bearing housing bore is a precisely machined cylindrical opening within a bearing block or housing that accommodates and supports rolling element bearings (ball, roller, or tapered bearings). Its primary function is to provide accurate radial and axial positioning of the bearing outer ring, ensuring proper shaft alignment, load distribution, and rotational stability in mechanical systems. The bore's dimensional accuracy, surface finish, and geometric tolerances directly impact bearing performance, lifespan, and system reliability.

Working Principle

The bearing housing bore operates on the principle of interference or clearance fit with the bearing outer ring. It constrains the bearing radially and axially while transferring operational loads (radial, axial, and moment loads) from the rotating shaft through the bearing to the stationary machine structure. Proper bore geometry ensures even load distribution across the bearing raceway, minimizes stress concentrations, and maintains lubrication integrity within the bearing assembly.

Materials

Typically manufactured from cast iron (GGG40, GGG50), ductile iron, cast steel (GS-52, G20Mn5), or aluminum alloys (AlSi10Mg, A356). Material selection depends on load capacity, thermal expansion requirements, corrosion resistance, and machining characteristics.

Technical Parameters

Parameter	Typical range	Notes & selection driver
Hardness	160-240 HB for cast iron, 140-190 HB for aluminum
Cylindricity	0.01-0.03 mm per 100 mm length
Surface Roughness	Ra 1.6-3.2 μm (63-125 μin)
Roundness Tolerance	IT6-IT7 grade
Bore Diameter Tolerance	H7 (ISO) or H6 for precision applications

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Standards

ISO 286-2, ISO 1101, DIN 7190, DIN 3760

Parent Products

This component is used in the following industrial products

Bearing block

A housing component that supports and aligns linear bearings within a guide system.

View Product Details

Engineering Analysis

Risks & Mitigation

Bore ovality causing uneven load distribution
Thermal expansion mismatch leading to bearing seizure
Corrosion pitting reducing fatigue life
Improper fit causing bearing creep or fretting

FMEA Triads

Trigger: Inadequate machining accuracy
Failure: Bore ovality exceeding tolerance
Mitigation: Implement statistical process control (SPC) for bore machining, use CMM verification, and apply corrective honing processes

Trigger: Thermal expansion coefficient mismatch
Failure: Bearing seizure during operation
Mitigation: Select housing materials with compatible thermal expansion, incorporate thermal analysis in design, and use appropriate fit selection based on temperature range

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance

ISO 286-2:2010 for bore diameter tolerances, ISO 1101:2017 for geometric tolerancing

Test Method

Coordinate measuring machine (CMM) verification per ISO 10360-2, surface roughness testing per ISO 4287, hardness testing per ISO 6506-1

Procurement Evaluation Criteria

A practical evidence checklist for RFQ preparation and supplier evaluation.

Technical documentation

Request current drawings, revision history, and a signed specification sheet.

Manufacturing capability

Verify equipment lists, process limits, capacity, and representative production evidence.

Inspection readiness

Confirm test methods, calibrated equipment, sampling plans, and traceable reports.

Supplier transparency

Check the legal entity, factory address, ownership, certifications, and direct contacts.

CNFX does not score or rank suppliers. Buyers must verify all claims and documents with the legal manufacturer before ordering.

Manufacturers of Bearing housing bore

Manufacturer profiles associated with Bearing housing bore.

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Compiled and source-reviewed by the CNFX editorial team. Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review

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Frequently Asked Questions

What is the difference between clearance fit and interference fit for bearing housing bores?

Clearance fit (e.g., H7/g6) allows easy bearing installation and accommodates thermal expansion but may cause bearing creep under load. Interference fit (e.g., H7/p6) prevents bearing rotation in the housing, improves load transfer, but requires precise temperature control during assembly.

How does bore surface finish affect bearing performance?

Poor surface finish (Ra > 3.2 μm) can cause micro-welding, increased friction, and premature bearing wear. Optimal finish (Ra 1.6-3.2 μm) ensures proper seating, reduces stress concentrations, and maintains lubrication film integrity.

Data Basis

Editorial classification, named public sources where available, and source-reviewed manufacturer records. See the editorial policy.

Preliminary Technical Classification

This page supports structured research, RFQ preparation, and supplier evaluation. It does not replace buyer-led supplier qualification, standards review, or technical approval.

Bearing housing bore