How is grip of wrench numbered in India?
In India, wrenches (spanners) are generally numbered according to the size of the nut or bolt they are meant to fit, which is based on the width across flats (AF)—the distance between the two opposite flat sides of a bolt head or nut. Here's how it works:
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🔧 Grip Numbering of Wrenches in India
Metric Sizes (most common in India)- Wrenches are labeled in millimeters (mm).
- For example: 8mm, 10mm, 12mm, 14mm, 17mm, 19mm, etc.
- This refers to the size of the nut/bolt the wrench fits (across flats).
- These are standardized under IS (Indian Standards) and compatible with ISO/metric system.
- Marked in fractions of inches: 1/4", 3/8", 7/16", 1/2", 9/16", etc.
- Still used in some legacy equipment or automobiles.
- Some older Indian wrench sets use numbers like 6, 8, 10, 12, 14, 17, 19, etc.
- These numbers often match the metric size in mm.
🔩 Double-Ended Spanners:
Often, these spanners have two different sizes on each end and may be marked like:
- 10x11, 12x13, 17x19, etc.
- These denote two different metric grip sizes.
🛠 Example from an Indian wrench set:
| Wrench Number | Grip Size (Across Flats) |
|---|---|
| 6 | 6 mm |
| 10 | 10 mm |
| 17 | 17 mm |
| 19 | 19 mm |
Summary:
- In India, "grip size" = metric size in mm, commonly printed directly on the wrench.
- The "number" on a wrench is essentially the same as the size of nut/bolt head in mm.
- IS standards follow the mtric system for most hand tools.
- Explain types of wrenches
Wrenches (or spanners, as they're also called in India and the UK) come in various types, each designed for specific applications, shapes of fasteners, and working conditions. Here's a detailed breakdown:
🔧 Types of Wrenches (Spanners)
1. Open-End Wrench
- Design: U-shaped open jaw on one or both ends.
- Use: Quick tightening or loosening of nuts/bolts with good access.
- Common Sizes: 6mm to 32mm (metric) or 1/4" to 1-1/4" (inch).
- ✅ Pros: Fast to use.
- ❌ Cons: Slips more easily, not suitable for high torque.
2. Box-End Wrench
- Design: Enclosed ring at the end (6-point or 12-point).
- Use: Full grip around nut/bolt head; better for tight spaces.
- ✅ Pros: Less slipping, more torque.
- ❌ Cons: Slower, needs more clearance.
3. Combination Wrench
- Design: One open end + one box end (same size).
- Use: Most versatile; open end for speed, box end for torque.
- ✅ Pros: Two functions in one tool.
- ❌ Cons: Fixed size per wrench.
4. Adjustable Wrench (Crescent Wrench)
- Design: Movable jaw, fits various sizes.
- Use: General purpose; fits both metric and imperial nuts.
- ✅ Pros: One tool for many sizes.
- ❌ Cons: Can slip if not adjusted tightly.
5. Socket Wrench (Ratchet Wrench)
- Design: Uses detachable sockets with ratchet handle.
- Use: Fast tightening/loosening without removing tool from nut.
- ✅ Pros: High speed + torque.
- ❌ Cons: Needs space for ratchet motion.
6. Allen Wrench (Hex Key)
- Design: L-shaped bar with hexagonal cross-section.
- Use: Screws with hex sockets (commonly in furniture, bikes).
- ✅ Pros: Compact, precise.
- ❌ Cons: Low torque, small sizes.
7. Torque Wrench
- Design: Looks like a socket wrench but with a torque gauge or setting.
- Use: To apply exact torque (e.g., engine bolts, mechanical assemblies).
- ✅ Pros: Prevents overtightening.
- ❌ Cons: Expensive, needs calibration.
8. Pipe Wrench (Stillson Wrench)
- Design: Heavy-duty wrench with serrated jaws.
- Use: Plumbing work—grips round pipes.
- ✅ Pros: Strong grip on round objects.
- ❌ Cons: Can damage soft materials.
9. Strap Wrench / Chain Wrench
- Design: Uses a strap or chain to grip irregular/round objects.
- Use: For polished or sensitive surfaces (e.g., water filters, PVC pipes).
- ✅ Pros: No scratches.
- ❌ Cons: Limited torque.
10. Spoke Wrench
- Design: Small tool with slotted edges.
- Use: Adjusting tension of bicycle wheel spokes.
- ✅ Pros: Specific and compact.
- ❌ Cons: Not universal.
11. Crowfoot Wrench
- Design: Open-end wrench head without handle; used with a ratchet.
- Use: For tight spaces where standard wrenches can’t reach.
- ✅ Pros: Great for engine work or under dashboards.
- ❌ Cons: Less torque than box-end.
🛠 Common Wrench Sets in India
- Double-ended Open Spanners
- Ring Spanners (Box-end)
- Combination Sets
- Adjustable Wrench (Shifting Spanner)
- Socket Sets (ratchets + sockets in mm)
- Allen Key Sets (mm and inch)
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