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D2208-16 – Standard Test Method Technical Guide
ASTM D2208-16 (Reapproved 2023) is a standard test method for determining the breaking strength of leather using the grab method. It is designed for light, soft leathers, boarded, sueded, embossed leathers, and narrow strap, welt, lace, and round belt leathers where Test Method D2209 is not suitable. The test method uses inch-pound units as the standard, with metric values in parentheses.
📐 Specimen Geometry and Types
As specified in Section 7 of the standard, the specimen preparation depends on the leather type:
| 🟦 Specimen Category | 📏 Length | 📐 Width |
|---|---|---|
| Wide, flat leathers | 6 in (152 mm) | 3 in (76 mm) |
| Narrow strap, welting, lace, round belt leathers | 6 in (152 mm) | As supplied |
The direction of the long dimension relative to the backbone should be recorded.
⚙️ Test Procedure and Speed Selection
The test is conducted using a testing machine as described in Test Method D2209. The key settings are summarized below:
| 📊 Parameter | 🎯 Specification |
|---|---|
| Jaw separation speed | 10 in./min ± 2 in./min |
| Jaw face dimensions (one jaw) | 1 in. × 1 in. (25.4 mm × 25.4 mm) |
| Jaw face dimensions (other jaw) | 1 in. × 1½ in. (25.4 mm × 38 mm) or more |
| Thickness gauge | Dead-mass type per Test Method D1813 |
| Steel scale | Graduated to 0.02 in (0.5 mm) |
The specimen is clamped in the jaws, and the force required to rupture the leather is measured, along with percent elongation at rupture.
⚠️ This test method is not recommended for breaking loads over 500 lbf (2200 N) due to the risk of specimen slippage in the jaws.
📊 Key Measured Properties
The breaking load is measured in pound-force (lbf) or newtons (N), with a maximum recommended load of 500 lbf (2200 N). The percent elongation at rupture is calculated at the specified jaw separation speed. Conditioning of specimens according to Practice D1610 is recommended for accuracy.
💡 For accurate results, condition the leather specimens according to Practice D1610 before testing.
❓ Frequently Asked Questions
🔍 What is the scope of this test method?
This test method covers the breaking strength of leather by the grab method for light, soft leathers, boarded, sueded, embossed leathers, and narrow strap, welt, lace, and round belt leathers. It does not apply to wet blue.
💡 How are specimens prepared for this test?
For wide, flat leathers, the specimen is 6 in. by 3 in. For narrow leathers, it is 6 in. long with the width as supplied. The orientation relative to the backbone must be noted.
⚡ What is the jaw separation speed?
The jaw separation speed is 10 in./min ± 2 in./min as specified in the standard.
📌 What are the limitations of this test method?
The test method is not recommended for breaking loads over 500 lbf (2200 N) due to specimen slippage. It also does not apply to wet blue.