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D2475-22 – Standard Test Method Technical Guide
ASTM D2475-22 establishes specifications for felt rolls and sheets used in mechanical applications. It outlines dimensional tolerances, mass requirements, and references related standards to ensure quality and consistency in felt manufacturing.
📐 Scope and Referenced Documents
This specification covers all standard felt types suitable for mechanical use, excluding woven, knitted, or bonded felts. It references ASTM D123 for terminology, D461 for test methods, Federal Standard C-F-206, and SAE J314b.
📏 Terminology and Material Classification
Felt is defined as a textile structure with interlocking fibers. The standard includes classes like 26S1 (white) and 26S4 (gray), each with specific thickness and mass properties as detailed in Table 1.
⚙️ Dimensional Specifications and Tolerances
Table 1 provides nominal thickness and mass values with tolerances. For instance, class 26S1 felt has a nominal thickness of 0.125 in. with a tolerance of ±0.014 in., and a mass of 1.50 lb/yd² with a tolerance of ±0.10 lb/yd².
| 🟦 Class | 📏 Thickness (in.) | 📐 Thickness Tol. (in.) | 🎯 Mass (lb/yd²) | ⚡ Mass Tol. (lb/yd²) |
|---|---|---|---|---|
| 26S1 | 0.125 | ±0.014 | 1.50 | ±0.10 |
| 26S4 | 0.188 | ±0.016 | 2.25 | ±0.15 |
| 26S4 | 0.250 | ±0.020 | 3.00 | ±0.20 |
| 26S4 | 0.375 | ±0.024 | 4.50 | ±0.30 |
| 26S4 | 0.500 | ±0.030 | 6.00 | ±0.40 |
| 26S4 | 0.750 | ±0.040 | 9.00 | ±0.50 |
| 26S4 | 1.000 | ±0.051 | 12.00 | ±0.60 |
Remember that tolerances for cut parts may be slightly different from sheets; always verify specific requirements for your application.
This standard uses inch-pound units as standard; SI units are for reference only. Ensure compatibility with your measurement systems.
❓ Frequently Asked Questions
🔍 What does ASTM D2475-22 cover?
It covers standard felt types in rolls and sheets for mechanical use, including special-purpose felts, but excludes woven or bonded felts.
💡 What are the basic units of measurement?
Inch-pound units are the standard, with SI units provided as informational only.
⚡ How are tolerances defined for thickness and mass?
For example, class 26S1 white felt has thickness tolerance ±0.014 in. and mass tolerance ±0.10 lb/yd² for sheets.
📌 Which standards are referenced in this specification?
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