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Mechanical engineering · radial shaft seals

Oil Seal Size Chart

Find a radial oil-seal candidate by shaft diameter, nominal housing bore, and seal width, then compare a bounded metric and inch reference with live unit conversion.

Dimensions
d × D × b
Units
mm canonical · inch display
Default
20 × 35 × 7 mm
Scope
Dimensional identification only

Reverse dimension finder

Find an Oil Seal by Size

Enter one, two, or three measured dimensions. Exact listed triplets rank first; otherwise the tool reports the closest included dimensional candidate and its deviation.

Use d for shaft diameter, D for nominal housing bore, and b for axial seal width. The default 20 × 35 × 7 mm example is verified in the Timken small-bore metric seal table.

Oil seal shaft, housing bore, and width dimensions Schematic radial shaft lip seal showing shaft diameter d, nominal housing bore D, and axial seal width b for the default 20 by 35 by 7 millimetre candidate. d = 20 mm D = 35 mm b = 7 mm Shaft Housing Sealing lip
Original schematic for identification only. The geometry explains d, D, and b; it is not a manufacturing drawing or installation template.
Candidate
20 × 35 × 7 mm
Shaft diameter d
20 mm
Housing bore D
35 mm
Seal width b
7 mm

Dimensional candidate only

A matching d × D × b triplet does not prove interchangeability. Verify lip construction, seal material, actual seal OD/interference, speed, pressure, temperature, shaft and housing tolerances, lubricant compatibility, and the current manufacturer specification.

Bounded dimensional reference

Oil Seal Size Chart

36 representative radial oil-seal dimensional triplets from Timken metric and inch product references, deduplicated by nominal shaft, housing bore, and width.

Search a size such as 20 35 7, filter the native unit family, or choose View to load a row into the finder. Display units can be switched in the finder above.

Scroll horizontally to view additional columns and vertically to view additional rows. Column headers remain visible while scrolling.

Bounded radial oil-seal dimensional reference. Size identifies a candidate only; verify the complete current manufacturer specification before replacement or design use.
Displayed dimensions Alternate-unit size Actions
5 × 16 × 6 mm Metric-native 5 mm 16 mm 6 mm 0.197 × 0.63 × 0.236 in
6 × 16 × 7 mm Metric-native 6 mm 16 mm 7 mm 0.236 × 0.63 × 0.276 in
7 × 22 × 7 mm Metric-native 7 mm 22 mm 7 mm 0.276 × 0.866 × 0.276 in
8 × 17 × 5 mm Metric-native 8 mm 17 mm 5 mm 0.315 × 0.669 × 0.197 in
8 × 24 × 7 mm Metric-native 8 mm 24 mm 7 mm 0.315 × 0.945 × 0.276 in
9 × 18 × 7 mm Metric-native 9 mm 18 mm 7 mm 0.354 × 0.709 × 0.276 in
10 × 17 × 3 mm Metric-native 10 mm 17 mm 3 mm 0.394 × 0.669 × 0.118 in
10 × 20 × 7 mm Metric-native 10 mm 20 mm 7 mm 0.394 × 0.787 × 0.276 in
10 × 30 × 7 mm Metric-native 10 mm 30 mm 7 mm 0.394 × 1.181 × 0.276 in
11 × 22 × 7 mm Metric-native 11 mm 22 mm 7 mm 0.433 × 0.866 × 0.276 in
12 × 18 × 3 mm Metric-native 12 mm 18 mm 3 mm 0.472 × 0.709 × 0.118 in
12 × 22 × 7 mm Metric-native 12 mm 22 mm 7 mm 0.472 × 0.866 × 0.276 in
12 × 25 × 5 mm Metric-native 12 mm 25 mm 5 mm 0.472 × 0.984 × 0.197 in
12 × 28 × 7 mm Metric-native 12 mm 28 mm 7 mm 0.472 × 1.102 × 0.276 in
14 × 22 × 5 mm Metric-native 14 mm 22 mm 5 mm 0.551 × 0.866 × 0.197 in
14 × 25 × 7 mm Metric-native 14 mm 25 mm 7 mm 0.551 × 0.984 × 0.276 in
14 × 35 × 7 mm Metric-native 14 mm 35 mm 7 mm 0.551 × 1.378 × 0.276 in
20 × 30 × 7 mm Metric-native 20 mm 30 mm 7 mm 0.787 × 1.181 × 0.276 in
20 × 32 × 7 mm Metric-native 20 mm 32 mm 7 mm 0.787 × 1.26 × 0.276 in
20 × 35 × 7 mm Metric-native 20 mm 35 mm 7 mm 0.787 × 1.378 × 0.276 in
20 × 40 × 7 mm Metric-native 20 mm 40 mm 7 mm 0.787 × 1.575 × 0.276 in
22 × 32 × 7 mm Metric-native 22 mm 32 mm 7 mm 0.866 × 1.26 × 0.276 in
22 × 35 × 7 mm Metric-native 22 mm 35 mm 7 mm 0.866 × 1.378 × 0.276 in
25 × 37 × 7 mm Metric-native 25 mm 37 mm 7 mm 0.984 × 1.457 × 0.276 in
32 × 50 × 10 mm Metric-native 32 mm 50 mm 10 mm 1.26 × 1.969 × 0.394 in
38 × 62 × 7 mm Metric-native 38 mm 62 mm 7 mm 1.496 × 2.441 × 0.276 in
40 × 50 × 8 mm Metric-native 40 mm 50 mm 8 mm 1.575 × 1.969 × 0.315 in
50 × 110 × 10 mm Metric-native 50 mm 110 mm 10 mm 1.969 × 4.331 × 0.394 in
68 × 90 × 12 mm Metric-native 68 mm 90 mm 12 mm 2.677 × 3.543 × 0.472 in
75 × 90 × 8 mm Metric-native 75 mm 90 mm 8 mm 2.953 × 3.543 × 0.315 in
80 × 110 × 12 mm Metric-native 80 mm 110 mm 12 mm 3.15 × 4.331 × 0.472 in
120 × 150 × 12 mm Metric-native 120 mm 150 mm 12 mm 4.724 × 5.906 × 0.472 in
0.375 × 0.75 × 0.25 in Inch-native 9.53 mm 19.05 mm 6.35 mm 0.375 × 0.75 × 0.25 in
1.75 × 2.75 × 0.5 in Inch-native 44.45 mm 69.85 mm 12.7 mm 1.75 × 2.75 × 0.5 in
2.375 × 3.601 × 0.437 in Inch-native 60.33 mm 91.47 mm 11.1 mm 2.375 × 3.601 × 0.437 in
4.625 × 5.875 × 0.625 in Inch-native 117.47 mm 149.22 mm 15.88 mm 4.625 × 5.875 × 0.625 in

Canonical matching values are stored in millimetres. Metric rows come from a deliberately bounded subset of Timken’s small-bore metric product table/current metric catalog; inch rows use Timken’s nominal housing-bore field rather than actual seal OD. Full catalog CSV export is disabled.

How to Read Oil Seal Sizes

For the dimensional lookup on this page, a seal is written as d × D × b: shaft diameter, nominal housing bore, and axial seal width. A 20 × 35 × 7 mm seal therefore fits a 20 mm shaft-size family, a nominal 35 mm housing bore, and a 7 mm axial width.

d — Shaft diameter
The nominal diameter of the shaft at the sealing surface.
D — Housing bore
The nominal bore into which the seal is installed. It is not always numerically identical to the manufactured seal outside diameter because the OD may incorporate installation interference.
b — Seal width
The nominal axial width of the seal envelope.

How to Measure an Oil Seal for Replacement

  1. Read any legible markings before measuring; a manufacturer designation can identify details that dimensions cannot.
  2. Measure the shaft at the seal running surface to establish d. Check more than one location if wear is visible.
  3. Measure the clean housing bore for D when practical rather than assuming a worn or elastomer-covered seal OD equals the bore.
  4. Measure the seal’s axial width b across the body without compressing flexible lips or flanges.
  5. Keep the measured unit system as recorded, enter all three values, and use the reported dimensional differences to judge whether the candidate is plausibly the intended nominal size.
  6. Confirm the complete current manufacturer specification before ordering or installing the replacement.

What a Dimensional Match Does — and Does Not — Prove

A d × D × b match is useful for narrowing the search, but it is not an interchange approval. Manufacturer seal tables distinguish construction features beyond the three nominal dimensions.

Matched here

Nominal shaft diameter, nominal housing bore, axial width, native unit family, and dimensional difference from your measurements.

Still verify

Lip count and geometry, spring arrangement, OD construction, elastomer, pressure capability, rotation, temperature, speed, lubricant, shaft finish, runout, and installation requirements.

Do not treat “closest” as compatible

The closest included row is simply the lowest dimensional-distance candidate in this bounded dataset. The tool never interpolates a nonexistent size or certifies substitution.

Shaft and Housing Requirements Matter

Even a correctly sized radial lip seal can leak or wear rapidly when the running surface, bore, alignment, or installation geometry is wrong. Check the current seal manufacturer’s limits for shaft and bore tolerances, surface finish, lead, eccentricity/runout, chamfers, installation tools, and damage criteria.

The distinction between housing bore and actual seal OD is especially important on some inch products. Timken’s individual inch records can list an OD slightly larger than the nominal housing bore to provide the intended interference; this page matches on the nominal housing-bore field.

For the surrounding rotating component, see the Turn2Engineering Shaft Design Guide.

Metric vs Inch Oil Seals

Metric and inch-native seals should retain their original size identity. This page converts dimensions with the exact relationship 1 in = 25.4 mm so you can compare measurements, but a calculated conversion does not create a standard nominal size in the other family.

For example, the inch-native Timken 330385 record uses a 0.375 in shaft, 0.750 in nominal housing bore, and 0.250 in width. Those are 9.525 mm, 19.05 mm, and 6.35 mm when converted; they should not be rounded into a different metric designation.

Oil Seal Lip Types and Materials

The Timken metric source distinguishes single-lip and multiple-lip constructions, spring details, OD types, and elastomers such as NBR and FKM. Those fields are deliberately not converted into an automatic recommendation because suitability depends on the application.

Primary sealing lip
Maintains contact with the rotating shaft to retain lubricant or exclude media according to the seal design.
Auxiliary or multiple lip
Can add exclusion or secondary sealing functions, but geometry and orientation are manufacturer-specific.
NBR / FKM examples
Common elastomer families shown in manufacturer catalogs; temperature and fluid compatibility must be checked against the exact material and service.

Oil Seal Size Lookup Examples

Example 1: exact metric triplet

Measured: d = 20.00 mm, D = 35.00 mm, b = 7.00 mm.

The finder returns 20 × 35 × 7 mm as an exact included dimensional candidate because all three canonical values match a source-verified Timken metric row.

Sanity check: the result still does not specify lip design, elastomer, pressure or speed capability, so the exact replacement must be verified.

Example 2: an inch-native housing-bore match

Measured: d = 0.375 in, D = 0.750 in, b = 0.250 in.

The bounded inch reference includes this triplet from Timken part 330385. Timken also lists the actual seal OD as 0.754 in, illustrating why housing bore and manufactured seal OD should not be treated as the same field.

Sanity check: use the manufacturer record to verify construction and material before substitution.

Standards, Dataset Scope, and Source Method

Dataset: T2E-OIL-SEAL-DIM-1 · bounded radial oil-seal dimension reference · 36 deduplicated triplets · canonical unit: mm.

ISO 6194-1:2007 provides standards context for rotary shaft lip-type seal nominal dimensions and tolerances. Its copyrighted tables and figures are not reproduced here. The published rows are a limited transformed reference acquired from official Timken product information; the default 20 × 35 × 7 mm triplet was also cross-checked against current SKF product information.

Dataset and Source-Check Details

Publisher
Turn2Engineering
Source checked
August 19, 2026
Source-controlled fields
Native size family, shaft diameter, nominal housing bore, seal width
Calculated fields
Alternate-unit display and dimensional deviations only
Conversion
1 in = exactly 25.4 mm
Matching
Discrete exact/nearest lookup; no interpolation or extrapolation
Rights decision
Limited transformed educational reference; no complete ISO or manufacturer catalog reproduction
Download decision
Full CSV disabled; visible row/result copying only
Missing values
Shown as an em dash and excluded from matching; never converted to zero
Maintenance trigger
Recheck source status, catalog revisions, rights terms, and regression rows at least annually or when a source changes

Oil Seal Size Chart FAQ

They commonly identify shaft diameter × nominal housing bore × axial width for dimensional lookup, but the exact notation should still be confirmed against the manufacturer.

Identify the Size, Then Verify the Application

Use d × D × b to identify the closest dimensional candidate, preserve whether the source size is metric- or inch-native, and then confirm the exact seal construction and operating limits with the current manufacturer before replacement or design use.

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