Description
QD21H100 Timing Pulley, 21 Teeth, H Pitch
The QD21H100 is a 21-tooth H (0.500 in trapezoidal) timing pulley. It mounts with an industry-standard bushing, sold separately, 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 | QD21H100 |
| 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 | Accepts SH bushing (not included) |
| Face Width | 1.312 in |
| Overall Length | 1.312 in |
| Construction | Quick Disconnect Hub |
| Flange Material | Steel |
| Material | Ductile Iron (no sintered or powdered metal) |
| Finish | Black Oxide |
| Weight | 1.459 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 QD21H100 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 QD21H100 interchanges with these equivalent part numbers, per published manufacturer interchange data:
| Manufacturer | Equivalent Part Number |
|---|---|
| Martin | 21H100 SH |
| TB Woods® | 21H100 |
| Regal Rexnord (Browning®) | 21H100SH |
| Mitsuboshi | QD21H100 |
| Jason Industrial | 21H100SH |
| Ametric | 21H100.SH |
| Powerdrive | QD21H100 |
| Continental (ContiTech) | 21H100-SH |
Always verify dimensions and bore size before substituting part numbers across manufacturers.
Buying in bulk? Save on volume.
Multi-unit and OEM quantities qualify for volume discounts. Call or email for a quantity quote.
Frequently Asked Questions
What belts fit the QD21H100 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 QD21H100 replace the Martin 21H100 SH?
Yes. Published interchange data crosses the QD21H100 directly to the Martin 21H100 SH, as well as TB Woods 21H100, Regal Rexnord 21H100SH, Mitsuboshi QD21H100. Verify dimensions and bore before ordering.
Does the QD21H100 ship from Houston?
Yes. Stock items ship same day from our Houston, Texas warehouse. Call (888) 203-2358 to confirm availability.
All 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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