Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
ASME B107.25-2002 — Pliers: Performance Test Methods
🧪 ASME B107.25-2002 is the B107-series standard devoted to performance test methods for pliers, replacing ASME B107.25M-1996. It details the purpose, apparatus, procedures, and performance specifications for the functional testing of pliers, serving as the bridge between the product standards (such as B107.22M, B107.23, B107.24, and B107.27) and product inspection. Manufacturers, purchasers, and third-party laboratories use this Standard to evaluate whether pliers conform to the performance requirements defined in the applicable product standards. The principal changes in this edition are updated references and the elimination of test methods not referenced in other standards.
💡 While standards like B107.22M answer “what a plier should look like and what performance it should deliver,” B107.25 answers “how to verify that performance objectively and repeatably.” Together they close the quality-evaluation loop.
1. Scope and Safety Requirements 📌
This Standard details the purpose, apparatus, procedures, and performance specifications for the functional testing of pliers, and is intended for use by manufacturers, purchasers, and other persons involved in evaluating pliers products. Section 2 (Safety) stresses that many of the tests described are inherently hazardous, so adequate safeguards for persons and property shall be employed, referring also to the HTI “Guide for Hand Tools — Selection, Safety Tips, Proper Use and Care” for additional information.
🚨 In handle load tests the pliers can fracture suddenly and eject fragments. Test personnel must wear eye protection and gloves, shield the test rig with guards or screens, and control loading and unloading at all times. Never hold the specimen by hand across the fold zone under load.
2. Apparatus and Definitions 🔬
Section 4 defines the key terms used in the tests so that all parties understand them consistently:
| Term | Definition |
|---|---|
| deflection | movement under load |
| force | the action of one body on another that changes, or tends to change, the motion of the body acted on |
| initial load | a small force applied to the handles before the major load during the handle load test |
| major load | the force applied to the handles during the handle load test to deflect the handles |
| moment | a measure of the tendency of a force to rotate a body about an axis |
| permanent set | the difference in distance, measured at a right angle to the centerline, between handles before and after application and removal of the major load (plastic deformation) |
| room temperature | 60°F to 80°F |
| scored surface | serrated or crosshatched surface to enhance gripping ability |
3. Typical Test Procedures 🧪
Section 5 specifies the test procedures. The most characteristic is the handle load test (Fig. 1): the pliers are clamped in the specified orientation, an initial load is applied at the defined point on the handles through a load cell, then the major load is gradually applied to the specified value while deflection is measured; after unloading, permanent set is measured. The test evaluates both overall strength under load and elastic recovery. A jaw opening and closing test (Fig. 2, concept design) evaluates the smoothness and consistency of jaw opening and closing across the rated range. Each product standard references these test methods with its own load positions, load values, and acceptance limits.
| Test Item | Apparatus Focus | Primary Measurement/Criterion |
|---|---|---|
| Handle load test | Test fixture + load cell (Fig. 1) | Deflection, permanent set, no cracking or breaking |
| Jaw opening/closing test | Opening/closing actuator (Fig. 2 concept) | Smooth travel, reliable indexing |
| Grip/clamping tests | Standard specimens and grips | Gripping force and slip resistance (referenced by product standards) |
| Hardness tests | Rockwell/indentation apparatus (ASTM E18/E384) | Handle and jaw hardness ranges |
4. Relationship with Product Standards 📚
B107.25 defines no product construction or dimensions; it provides the “performance test toolbox” for the plier product standards (e.g., B107.22M slip joint pliers, B107.23 multiple position adjustable pliers, B107.24 locking pliers, B107.27 electrical connector pliers). Each product standard references this Standard in its Tests section and supplies product-specific parameters (e.g., Table 7 Test Parameters, Table 8 wire sizes). This “product standard + method standard” architecture keeps test judgments uniform and comparable across the whole B107 plier family.
⚠️ Watch the edition correspondence when referencing B107.25: a product standard (e.g., B107.27-2003) may reference the earlier B107.25M-1996 or this B107.25-2002 edition. Agree on one edition between buyer and seller and execute the tests to that edition’s parameters; mixing editions makes results incomparable.
5. Engineering Practice Essentials 🛠️
- 🔍 Test planning: identify the applicable product standard and the test methods/parameters it references, then prepare a load cell and fixture of adequate capacity.
- 🔧 Execution: control loading rate and temperature (room temperature, 60°F–80°F); record initial load, major load, deflection, and post-unload permanent set.
- 📋 Safety: isolate the test area, wear personal protective equipment, and verify the fixture is tightly secured — the minimum protection for test personnel.
- 📊 Reporting: the report should state the standard edition, test parameters, specimen identification, and conclusions for full traceability.
6. Frequently Asked Questions ❓
❓ Q: What is the relationship between B107.25 and the plier product standards?
A: B107.25 is a method standard that says how to test; the product standards (e.g., B107.24) say what performance is required and reference B107.25 to verify it. The two are used together.
A: B107.25 is a method standard that says how to test; the product standards (e.g., B107.24) say what performance is required and reference B107.25 to verify it. The two are used together.
❓ Q: Why does the Standard stress that the tests are hazardous?
A: Handle load tests apply loads near or beyond the tool’s design limit, so the body can fracture without warning and eject fragments; test specimens can also fly out of the grips. Isolation and guards are therefore mandatory.
A: Handle load tests apply loads near or beyond the tool’s design limit, so the body can fracture without warning and eject fragments; test specimens can also fly out of the grips. Isolation and guards are therefore mandatory.
🔍 Q: Why measure permanent set only after unloading?
A: The residual handle-spacing difference after unloading represents unrecoverable plastic deformation. Excessive permanent set means the pliers will gradually “open up” in service with degraded gripping — an indication of poor quality.
A: The residual handle-spacing difference after unloading represents unrecoverable plastic deformation. Excessive permanent set means the pliers will gradually “open up” in service with degraded gripping — an indication of poor quality.
❓ Q: How are the initial load and major load values chosen?
A: Values are specified by each product standard for its sizes (e.g., Table 7 in B107.23). Typically the initial load removes assembly slack and the major load represents a set proportion of rated capacity; follow the cited edition’s parameters.
A: Values are specified by each product standard for its sizes (e.g., Table 7 in B107.23). Typically the initial load removes assembly slack and the major load represents a set proportion of rated capacity; follow the cited edition’s parameters.
