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ASME B107.38M-1998 (2004) — Electronic Pliers
🔧 ASME B107.38M-1998 (2004) is the first American National Standard dedicated to pliers used in the electronics industry within the ASME B107 Hand Tools and Accessories series. It establishes the dimensional and functional characteristics of electronic pliers suitable for gripping, holding, and/or manipulating small objects; some pliers are also provided with cutting edges suitable for cutting small-diameter wire. Developed by the ASME B107 Standards Committee with major technical contributions from the Plier Standards Committee of the Hand Tools Institute (HTI), the standard was approved by the American National Standards Institute (ANSI) in July 1998 and reaffirmed without technical changes in 2004.
💡 In electronics assembly, instrument repair, and precision mechanics, jaw shape, overall length, and cutting-edge quality directly determine working accuracy. B107.38M turns “electronic pliers” into a standardized product family that can be specified, verified, and compared across manufacturers.
1. Scope and Product Positioning 📌
The scope of this Standard is precise: it covers the dimensional and functional characteristics of electronic pliers suitable for gripping, holding, and/or manipulating small objects in the electronics industry and similar precision work; certain models may also carry cutting edges for shearing small-diameter wire. The Standard explicitly states that the inclusion of dimensional and functional data does not imply that all products described are stock production sizes — consumers should consult manufacturers for the list of stock sizes.
⚠️ B107.38M is a dimensional/functional specification, not a safety standard. It is designed to be used together with ASME B107.25M (Pliers — Performance Test Methods), which defines the strength and functional test procedures. Quote both standards in your specification and acceptance documents.
2. Classification System: Type, Class, and Style 🔩
The Standard organizes electronic pliers into five Types by jaw shape; the Chain Nose type is further divided into five Classes. Each type/class may be supplied in either of two jaw styles. This three-level “Type–Class–Style” scheme is the first step in selection:
| Type / Class | Jaw Characteristics | Typical Use |
|---|---|---|
| Type I Flat Nose | Straight, wide flat jaws with large gripping area | Bending leads, holding flat parts, forming |
| Type II Class 1 Chain Nose, Long Nose Without Side Cutter | Long tapered jaws, no side cutting edge | Reaching into deep cavities, twisting, fine work |
| Type II Class 2 Chain Nose, Long Nose With Side Cutter | Long tapered jaws plus side cutting edge | Holding and cutting small wire in one operation |
| Type II Class 3 Chain Nose, Curved Nose | Jaws curved near the tip | Angled access in confined spaces, retaining rings |
| Type II Class 4 Chain Nose, Short Nose | Short, stout jaws with high grip force | Pulling, twisting short leads, tight fits |
| Type II Class 5 Chain Nose, Subminiature | Miniature pin-like jaws | Watchmaking and micro-instrument work |
| Type III Long Nose With Tip Cutter | Long nose with cutting edge at the tip | Trimming solder points, cutting fine leads |
| Type IV Needle Nose | Very fine needle-like jaws, no cutting edge | Threading through PCB holes, tensioning rings |
| Type V Round Nose | Tapered circular-section jaws | Forming wire loops and terminal wrap forms |
All types and classes above shall be available with one of the following jaw styles per Section 6: Style A — Smooth Jaw or Style B — Serrated Jaw. Smooth jaws avoid marring coated leads and finished surfaces; serrated jaws provide positive, slip-resistant gripping.
3. Dimensional and Functional Requirements 📏
The body of the Standard presents figures and tables giving the governing dimensions for each of the five plier types: overall length, jaw length and width, closed-jaw gap, effective cutting-edge length, and pivot location. Dimension tables are organized by the combination of type, class, and style — for example, the jaw width of the Type I flat-nose pliers and the nose taper of each Class of the Type II series. The Standard notes that the illustrations are descriptive and not restrictive, and are not intended to preclude the manufacture of pliers that otherwise conform to the Standard.
Functional characteristics
- Cutting capability: cutting models shall shear small-diameter wire cleanly within the rated size range; after closing, the edges shall not show significant gaps or chipping.
- Gripping function: closed jaws shall hold small parts securely; serrated jaws must not damage plated leads and delicate components.
- Operating feel: handles shall open and close smoothly without binding, and the tool body shall be free of burrs and sharp edges that impair use.
4. Testing Methods and Surface Quality 🧪
Testing requirements are incorporated by normative reference: ASME B107.25M-1996, Pliers — Performance Test Methods, governs strength, jaw deformation, and cutting-edge performance test procedures and acceptance criteria; ASME B46.1-1995, Surface Texture (Surface Roughness, Waviness, and Lay), provides the basis for specifying critical surface finish. Manufacturing and inspection should follow these methods on a sampling basis and keep records.
⚠️ Cutting edges wear with use. Rejection criteria should be based on the test conditions of B107.25M rather than subjective feel; repeatedly cutting hard steel wire accelerates edge damage — electronic pliers should be used only within their rated soft-wire range.
5. Engineering Practice Essentials 🛠️
- 🔍 Match the tool to the task: pick Type IV needle-nose or Type II Class 5 subminiature for tiny parts; Type II Class 2 or Type III for wire cutting; Type V round-nose for forming loops.
- 🔧 ESD considerations: in electronics assembly, choose models with electrostatic-discharge-safe (ESD) handles and use a grounded wrist strap. The Standard itself does not mandate handle materials — the manufacturer declares suitability for the intended environment.
- 📊 Edge care: cut only soft wire within the rated range; clean the pivot regularly and lubricate with a suitable light oil to keep the action smooth.
- 📋 Procurement and acceptance: request inspection reports and dimensional conformance statements referencing B107.38M and B107.25M, and verify that the type/class/style designation is marked on the product or packaging.
6. Frequently Asked Questions ❓
❓ Q: How does B107.38M differ from a general-purpose long-nose plier standard?
A: B107.38M targets small-object manipulation in the electronics industry with specific jaw sizes, closure accuracy, and fine-wire cutting requirements; general-purpose pliers in the B107.25M system need not meet such refined dimensional characteristics.
A: B107.38M targets small-object manipulation in the electronics industry with specific jaw sizes, closure accuracy, and fine-wire cutting requirements; general-purpose pliers in the B107.25M system need not meet such refined dimensional characteristics.
❓ Q: Style A smooth jaw or Style B serrated jaw — which should I choose?
A: Choose Style B when slip resistance and higher grip are needed; choose Style A when surfaces such as plated leads and precision terminals must not be scratched, optionally with rubber jaw protectors.
A: Choose Style B when slip resistance and higher grip are needed; choose Style A when surfaces such as plated leads and precision terminals must not be scratched, optionally with rubber jaw protectors.
❓ Q: Are all sizes in the dimensional tables stock items?
A: No. The Standard explicitly states that the listed dimensions do not imply stock production sizes; confirm the actual catalog sizes with the manufacturer in writing before purchase.
A: No. The Standard explicitly states that the listed dimensions do not imply stock production sizes; confirm the actual catalog sizes with the manufacturer in writing before purchase.
🔍 Q: What does the 2004 reaffirmation mean?
A: Reaffirmation means the committee reviewed the 1998 edition and found it still valid without technical changes; for users, this version remains the current effective edition.
A: Reaffirmation means the committee reviewed the 1998 edition and found it still valid without technical changes; for users, this version remains the current effective edition.
