Find a Service Center
- 12B-3 Chain Number
- 3 Strands
- 21 Teeth
- Without Hardened Teeth
- B Sprocket Style
description
- Maximum bores shown will accommodate standard keyseat and setscrew over keyseat. Slightly larger bores are possible with no keyseat, shallow keyseat, or setscrew at an angle to keyseat.
features
- Manufactured of high carbon steel
- Precise machining and processes ensure consistent finish and high quality
- Bores are concentric to pitch line, minimizing run out
- Chain rows are parallel and precisely spaced to increase longevity of sprocket and chain
| Hardened Teeth | Without Hardened Teeth |
| Hub Dia. | 100 mm |
| Bore Type | Reborable |
| Pitch Root Diameter | 115.8 mm |
| Root Diameter | 115.8 mm |
| Outside Dia. | 139.56 mm |
| Pin Diameter | 12.065 mm |
| Pitch Diameter [Min] | 127.8 mm |
| Hub Length Thru | 59.13 mm |
| Inch/Metric | Metric |
| Martin No. | 12B21 |
| Bore Style | Minimum Bore |
| Outside Dia. [Min] | 139.56 mm |
| Series | B |
| Pitch Diameter | 127.8 mm |
| No. of Strands Across | 3 |
| Sprocket Style | B |
| Chain Pitch | 19.05 mm |
| Length Through Bore | 69.98 mm |
| Bore Range [Min] | 20 mm |
| Bore Range [Max] | 70 mm |
| Material | Steel |
| No. of Teeth | 21 |
| Family Name | No. 12 - 19.050 mm Pitch - Triple - Type B & C |
| Caliper Diameter | 115.39 mm |
| Width Across Teeth | 49.78 mm |
| Single Strand Tooth Thickness | 10.87 mm |
| Chain No. | 12B, 12B-3 |
| Weight | 11.72 LB |
| EAN or UPC | 697950401768 |
