Description
21H100-6FS8 Timing Pulley, 21 Teeth, H Pitch
The 21H100-6FS8 is a 21-tooth H (0.500 in trapezoidal) timing pulley with a 3/4 in minimum plain bore, machined from ductile iron with a black oxide finish, built for 1 in wide belts. Machined from solid stock, never sintered or powdered metal.
Specifications

Dimension key for this construction type. Values for this part number are in the table below.
| Specification | Value |
|---|---|
| Part Number | 21H100-6FS8 |
| Teeth | 21 |
| Pitch | H (0.500 in trapezoidal) |
| For Belt Width | 1 in |
| Pitch Diameter | 3.3423 in |
| Outside Diameter | 3.2883 in |
| Flange Diameter | 3.574 in |
| Bore | 3/4 in minimum plain bore |
| Face Width | 1.312 in |
| Overall Length | 2.125 in |
| Hub Diameter | 2.625 in |
| Construction | Standard Hub |
| Flange Material | Steel |
| Material | Ductile Iron (no sintered or powdered metal) |
| Finish | Black Oxide |
| Weight | 3.77 lb |
| Country of Origin | United States. ISO 9001:2015 certified manufacturing. |
Applications
- Instrumentation, office equipment, and precision positioning drives
- 3D printers and desktop CNC equipment
- Robotics, medical devices, and packaging machinery
Belt Compatibility
The 21H100-6FS8 runs H (0.500 in trapezoidal) belts in 1 in width. The pitch is standardized, so belt and pulley brands can be mixed.
Cross Reference
The 21H100-6FS8 interchanges with these equivalent part numbers, per published manufacturer interchange data:
| Manufacturer | Equivalent Part Number |
|---|---|
| Dodge® | 21H100-MPB |
| Martin | 21H100 |
| TB Woods® | 21H100MPB |
| Regal Rexnord (Browning®) | 21HB100 |
| Mitsuboshi | 21H100-6FS8 |
| McMaster-Carr | 6495K91 |
| Grainger | 809V65 |
| Powerdrive | 21H100-6FS8 |
Always verify dimensions and bore size before substituting part numbers across manufacturers.
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Multi-unit and OEM quantities qualify for volume discounts. Call or email for a quantity quote.
Frequently Asked Questions
What belts fit the 21H100-6FS8 pulley?
H (0.500 in trapezoidal) timing belts in 1 in width from any manufacturer. The pitch is standardized, so belt and pulley brands can be mixed.
Does the 21H100-6FS8 replace the Dodge 21H100-MPB?
Yes. Published interchange data crosses the 21H100-6FS8 directly to the Dodge 21H100-MPB, as well as Martin 21H100, TB Woods 21H100MPB, Regal Rexnord 21HB100. Verify dimensions and bore before ordering.
Does the 21H100-6FS8 ship from Houston?
Yes. Stock items ship same day from our Houston, Texas warehouse. Call (888) 203-2358 to confirm availability.
Need a quote on 21H100-6FS8?
Houston warehouse, same-day shipping on stock items.
Call (888) 203-2358All third-party part numbers and trademarks referenced are the property of their respective owners. References are for compatibility identification only and do not imply affiliation or endorsement.
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