Dimension finder
Find a Needle Bearing by Size
Enter two or three measured dimensions to rank the closest included radial drawn-cup bearing sizes.
For HK/BK bearings without an inner ring, Fw is the diameter under the needle rollers. It is not a conventional inner-ring bore.
- A dimensional match is a candidate only. Verify construction, shaft/housing tolerances, raceway requirements, clearance, load, speed, sealing, and lubrication before substitution.
- Designation
- HK 2020
- Family
- HK · open ends
- Fw
- 20 mm
- Outside diameter D
- 26 mm
- Width C/B
- 20 mm
Bounded dimensional reference
Needle Bearing Size Chart
Representative common HK/BK radial drawn-cup dimensions verified against current manufacturer references.
Search by designation or filter the included family. Click View to load a row into the dimension diagram.
No included needle bearing matches these filters. Clear the filters or use the dimensional finder; the required size may be outside this bounded reference.
Scroll horizontally to view additional columns and vertically to view additional rows. Column headers remain visible while scrolling.
| Nominal dimensions | Inner ring | Action | |||||
|---|---|---|---|---|---|---|---|
| HK 0408 | HK | Drawn cup, open ends | 4 mm | 8 mm | 8 mm | No | |
| BK 0408 | BK | Drawn cup, closed end | 4 mm | 8 mm | 8 mm | No | |
| HK 0608 | HK | Drawn cup, open ends | 6 mm | 10 mm | 8 mm | No | |
| HK 0810 | HK | Drawn cup, open ends | 8 mm | 12 mm | 10 mm | No | |
| HK 1010 E | HK | Drawn cup, open ends | 10 mm | 14 mm | 10 mm | No | |
| HK 1210 E | HK | Drawn cup, open ends | 12 mm | 16 mm | 10 mm | No | |
| HK 1512 | HK | Drawn cup, open ends | 15 mm | 21 mm | 12 mm | No | |
| HK 2020 | HK | Drawn cup, open ends | 20 mm | 26 mm | 20 mm | No | |
| BK 2016 | BK | Drawn cup, closed end | 20 mm | 26 mm | 16 mm | No | |
| BK 2212 | BK | Drawn cup, closed end | 22 mm | 28 mm | 12 mm | No | |
| HK 2516 | HK | Drawn cup, open ends | 25 mm | 32 mm | 16 mm | No | |
| HK 3020 | HK | Drawn cup, open ends | 30 mm | 37 mm | 20 mm | No | |
Canonical values are stored in millimetres. The initial release intentionally uses a limited educational subset rather than reproducing a complete ISO or manufacturer catalogue. Bulk CSV export is disabled.
How to Read and Measure Needle Bearing Sizes
A needle bearing size is not fully described by a single “bore” value. For the common HK and BK drawn-cup bearings shown here, the useful replacement dimensions are the diameter under the rollers Fw, outside diameter D, and bearing width C/B.
- Fw
- Diameter under the needle roller complement. For these bearings without an inner ring, the shaft normally forms the inner raceway.
- D
- Nominal outside diameter of the drawn cup.
- C/B
- Nominal bearing width. Manufacturer notation can vary by product family.
Which needle bearing family are you measuring?
HK · open ends
Drawn-cup radial needle bearing open at both axial ends. This is the primary family represented by the chart.
BK · closed end
Drawn-cup radial needle bearing with a closed end. Keep it separate from an otherwise similar HK candidate because the construction is different.
Other needle bearing types
Machined-ring bearings, cage-only assemblies, and thrust needle bearings use different geometry or standards and should not be forced into this HK/BK lookup.
Practical replacement measurement
- Clean the bearing and inspect the designation before measuring; a readable marking is stronger evidence than dimensions alone.
- Measure outside diameter D and overall width with a suitable caliper or micrometer.
- For a drawn-cup bearing without an inner ring, measure the internal roller-complement diameter carefully and treat it as Fw rather than a conventional inner-ring bore.
- Identify whether the cup is open-ended or closed-ended before running the finder.
- Use the closest-size result as a candidate, then confirm the full current manufacturer specification for the application.
Needle Bearing Size Examples
Example 1: exact HK 2020 lookup
Measured: Fw = 20 mm, D = 26 mm, width = 20 mm, open-ended cup.
The finder returns HK 2020 as an exact dimensional candidate in this bounded reference because all three nominal dimensions match.
Sanity check: exact dimensions still do not prove interchangeability; verify the current product’s tolerances, raceway requirements, load, speed, and lubrication.
Example 2: imperfect field measurement
Measured: 19.98 mm × 26.04 mm × 20.02 mm for an open-ended cup.
The nominal HK 2020 row is only 0.02 mm, 0.04 mm, and 0.02 mm away on the three entered dimensions. The tool reports those individual deviations instead of calling the bearing “confirmed.”
Limitation: measurement error, wear, cup distortion, and installed versus uninstalled condition can affect what you measure.
Why Matching Dimensions Do Not Prove Interchangeability
Needle bearings with the same nominal envelope can differ in internal design and application limits. Treat this chart as an identification aid, not a project approval or interchange list.
Verify before substitution
Confirm shaft and housing tolerances, shaft raceway hardness and finish where applicable, radial internal clearance, cage or full-complement construction, seals, dynamic/static load ratings, limiting speed, lubrication, operating temperature, and mounting requirements.
For design selection beyond dimensions, continue to the Turn2Engineering Bearing Selection Guide.
Standards, Sources, and Dataset Scope
Dataset: Turn2Engineering Needle Bearing Dimensional Reference — Common Radial Sizes · v1.0.0 · 12 representative HK/BK rows · canonical unit: mm.
The standards below define scope and dimensional terminology for major needle-bearing families. This page does not reproduce complete ISO dimensional tables. The published reference rows are a bounded educational selection checked against current manufacturer product information, with inch values calculated from canonical millimetres using exactly 25.4 mm/in.
- ISO 3245:2023 — Needle roller bearings with drawn cup and without inner ring Primary standards scope for the HK/BK-style drawn-cup bearing geometry used on this page; complete ISO tables are not reproduced.
- ISO 1206:2023 — Rolling bearings — Needle roller bearings with machined rings Used to distinguish machined-ring scope from the drawn-cup HK/BK reference presented here. ISO publications remain copyright-protected.
- ISO 3030:2022 — Radial needle roller and cage assemblies Used to distinguish cage-only assemblies from complete drawn-cup bearings.
- ISO copyright and permissions Controls the decision not to reproduce complete ISO tables or enable a standards-derived bulk download.
- SKF — Drawn cup needle roller bearings Manufacturer product reference for HK/BK geometry, terminology, and representative dimensional checks.
- SKF — HK 2020 product data Direct product-level checkpoint for the default 20 × 26 × 20 mm example; released rows retain their own SKF product URL as machine-readable provenance.
Dataset and Source-Check Details
- Publisher
- Turn2Engineering
- Source checked
- August 16, 2026
- Source-controlled fields
- Designation, family, Fw, D, width, construction
- Calculated fields
- Inch display and dimensional deviations only
- Rights decision
- Limited transformed educational reference; no complete ISO/manufacturer table reproduction
- Download decision
- Bulk CSV disabled; selected-result copying only
- Missing values
- Shown as an em dash; never converted to zero
- Maintenance trigger
- Recheck on relevant ISO revision or material manufacturer range changes
Needle Bearing Size Chart FAQ
Designation conventions vary by family and manufacturer, so use the marking to find the official product record rather than assuming every digit directly encodes a dimension.
Measure Fw or the relevant inner dimension, outside diameter, and width, identify the bearing construction, then use the finder to locate a candidate and verify it against current manufacturer data.
For the drawn-cup bearings shown here without an inner ring, Fw is the diameter under the needle roller complement, so it should not be treated as the bore of a conventional inner ring.
No. Dimensions are only one part of compatibility; construction, tolerances, raceway requirements, load and speed ratings, sealing, lubrication, and operating conditions must also be checked.
Major needle-bearing families have standardized dimensional frameworks, but actual designations, constructions, and available products still depend on the bearing family and manufacturer.
Use Dimensions to Identify a Candidate, Then Verify the Bearing
Start with the bearing construction and three nominal dimensions: Fw, outside diameter D, and width C/B. Use the finder to narrow the included reference to the closest candidate, then confirm the complete current manufacturer specification before treating it as a replacement.