Side-by-Side Comparison
O-Rings & Rotary Seals
AS568 O-Ring Sizes vs. Rotary Shaft Oil Seals
Comparing 2 standards across 17 specifications. 17 key differences identified.
Comparing:
AS568 O-Ring Sizes
Rotary Shaft Oil Seals
Aerospace Standard AS568 (SAE AS568 / ISO 3601-1) classifies inch-series elastomeric O-rings into five cross-section diameter series: 000 (1/16" / 1.78 mm), 100 (3/32" / 2.62 mm), 200 (1/8" / 3.53 mm), 300 (3/16" / 5.33 mm), and 400 (1/4" / 6.99 mm).
Radial rotary shaft oil seals retain lubricating grease/oil and exclude contaminants along rotating shafts, standardized under DIN 3760 / ISO 6194 by three boundary dimensions: Shaft Diameter (d_1), Housing Bore Diameter (d_2), and Seal Width (b).
Specification Comparison Table
17 Parameters| Parameter / Spec | ||
|---|---|---|
|
Governing Standards
|
SAE AS568D / ISO 3601-1 Class A / MIL-STD-120 | DIN 3760 / ISO 6194-1 / RMA OS-1 |
|
000 Series Cross-Section (1/16")
|
CS: 0.070 in ± 0.003 in (1.78 mm ± 0.08 mm) | Dash -001 to -050 | — |
|
100 Series Cross-Section (3/32")
|
CS: 0.103 in ± 0.003 in (2.62 mm ± 0.08 mm) | Dash -102 to -178 | — |
|
200 Series Cross-Section (1/8")
|
CS: 0.139 in ± 0.004 in (3.53 mm ± 0.10 mm) | Dash -201 to -284 | — |
|
300 Series Cross-Section (3/16")
|
CS: 0.210 in ± 0.005 in (5.33 mm ± 0.13 mm) | Dash -309 to -395 | — |
|
400 Series Cross-Section (1/4")
|
CS: 0.275 in ± 0.006 in (6.99 mm ± 0.15 mm) | Dash -425 to -475 | — |
|
900 Series (Straight Thread Tube Fitting)
|
Boss seals for SAE J1926/MS33649 (Dash -901 to -932) | — |
|
Standard Static Gland Squeeze
|
15% to 30% radial or axial compression | — |
|
Standard Dynamic Gland Squeeze
|
10% to 20% radial compression (reduces friction and seal wear) | — |
|
Common Elastomer Polymers
|
NBR (Buna-N 70/90A), FKM (Viton), EPDM, Silicone (VMQ), FFKM (Kalrez) | — |
|
Dimension Format
|
— | [Shaft Diameter d₁] × [Bore Diameter d₂] × [Width b] in mm (e.g. 25 × 40 × 7) |
|
DIN 3760 Type A (ISO Form SC)
|
— | Elastomer-encased outer metal case, single sealing lip with garter spring |
|
DIN 3760 Type AS (ISO Form TC)
|
— | Elastomer-encased outer metal case, primary sprung lip + auxiliary dust wiper lip |
|
DIN 3760 Type B (ISO Form SB)
|
— | Exposed precision-ground metal outer diameter, pressed into cast iron housings |
|
Garter Spring Material
|
— | Carbon spring steel (Standard) or AISI 302/316 Stainless Steel (Corrosion/Marine) |
|
Shaft Surface Finish Requirement
|
— | Ra 0.2 to 0.8 µm (Rz 1.0 to 4.0 µm) plunge-ground without spiral machining lead |
|
Shaft Hardness at Seal Track
|
— | 45 to 60 HRC minimum (prevents grooving under seal lip) |