# BCK21-8MM-5/16"-A

**Manufacturer:** Ruland  
**MPN:** `BCK21-8MM-5/16"-A`

## Specifications

| Attribute | Value |
| --- | --- |
| Brand name | Ruland |
| Manufacturer name | Ruland |
| Manufacturer | Ruland |
| moq | 1 |
| MPN | BCK21-8MM-5/16"-A |
| multiple | 1 |
| qtyInStock | 0 |
| SKU | BCK21-8MM-5/16"-A |
| tierMinQty1 | 1 |
| tierMinQty2 | 10 |
| tierMinQty3 | 25 |
| tierMinQty4 | 50 |
| tierPrice1 | 193.02 |
| tierPrice2 | 115.81 |
| tierPrice3 | 96.51 |
| tierPrice4 | 86.86 |
| Large Bore B1 | 8 mm |
| Small Bore B2 | 0.313 in |
| Keyway K1 | 2 mm |
| Keyway K2 | NK |
| B1 Shaft Penetration | 0.804 in, 20.4 mm |
| B2 Shaft Penetration | 0.804 in, 20.4 mm |
| Outer Diameter OD | 1.313 in, 33.3 mm |
| Bore Tolerance | +.001 in / -.000 , +.03 mm / -.00 mm |
| Length L | 1.688 in / 42.9 mm |
| Hub Width LH | 0.590 in, 15.00 mm |
| Forged Clamp Screw | M3 |
| Screw Material | Alloy Steel |
| Hex Wrench Size | 2.5 mm |
| Screw Finish | Black Oxide |
| Seating Torque | 2.1 Nm |
| Number of Screws | 2 ea |
| Static Torque | 120 lb-in, 13.6 Nm |
| Angular Misalignment | 1.5° |
| Dynamic Torque Non-Reversing | 60 lb-in, 6.80 Nm |
| Parallel Misalignment | 0.006 in, 0.15 mm |
| Dynamic Torque Reversing | 30 lb-in, 3.40 Nm |
| Axial Motion | 0.016 in, 0.40 mm |
| Torsional Stiffness | 400 lb-in/Deg, 45 Nm/Deg |
| Maximum Speed | 10,000 RPM |
| Material Specification | Hubs: 2024-T351 Aluminum Bar |
| Temperature | -40°F to 200°F |
| Finish Specification | Sulfuric Anodized MIL-A-8625 Type II, Class 2 and ASTM B580 Type B Black Anodize |
| Country of Origin | USA |
| Weight (lbs ) | 0.1650 |
| UPC | 63452916512 |
| Note 1 | Stainless steel hubs are available upon request. |
| Note 2 | Torque ratings are at maximum misalignment. |
| Note 3 | Performance ratings are for guidance only. The user must determine suitability for a particular application. |

## Distributor availability

| Distributor | SKU | Price (USD) | Qty | Stock | MOQ |
| --- | --- | --- | --- | --- | --- |
| Ruland | BCK21-8MM-5/16"-A | 193.02 | 1 | None | 1 |

---
Structured data: `/python/html6/product/500/17000000/17457500/part_--BCK218MM5X2F16QUOTA---Ruland--40ca7b3be3.json`  
Search API: https://www.dataalchemy.com/api/  
MCP server: https://www.dataalchemy.com/mcp