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When your motion-control build demands repeatable, slip-free power transfer, a loose-fitting or poorly machined pulley becomes the weakest link in the chain. Engineers, makers, and small-batch manufacturers who run 5M pitch belt drives need a pulley that locks firmly to the shaft, seats the belt cleanly, and holds tolerance across thousands of cycles. These 5M timing belt pulleys with integrated step and keyway are machined to meet that standard.
Each pulley is precision-machined from aluminum alloy, featuring a stepped hub with a milled keyway slot for positive shaft engagement. Tooth count ranges from 15T to 80T, bore diameter from 8 mm (0.31 in) to 25 mm (0.98 in), and keyway width from 3 mm to 8 mm depending on variant. The belt-contact face is sized for standard 20 mm wide 5M synchronous belts.
Typical applications include CNC router X/Y axis drives, 3D printer extruder and gantry assemblies, robotic arm joint actuators, conveyor indexing systems, and laser engraver carriage drives — anywhere a 5M pitch synchronous belt pulley with keyway is required for a stepper motor or servo shaft.
The stepped hub with milled keyway slot locks the pulley to the shaft without slipping — critical for closed-loop positioning in CNC and robotics applications.
Choose from 15T to 80T to dial in your drive ratio. Standard and K-Type (extended hub) variants available for deeper shaft engagement on larger bore sizes.
Bore diameters from 8 mm to 25 mm (0.31"–0.98") cover common stepper motor, servo, and gearbox output shaft sizes. Each bore is matched to an appropriate keyway width.
Lightweight aluminum alloy body reduces rotational inertia for faster acceleration and deceleration — ideal for high-cycle automation and rapid-traverse CNC axes.
Tooth profile and flange geometry are matched to standard 20 mm wide 5M synchronous belts, ensuring full tooth engagement and even load distribution across the belt width.
Each variant ships as a single pulley. Order the quantity you need for your drive system — mix tooth counts and bore sizes in a single order to build complete drive pairs.
| Belt Pitch | 5M (5 mm tooth pitch) |
|---|---|
| Belt Width Compatibility | 20 mm |
| Tooth Count (Types) | 15T, 16T, 18T, 19T, 20T, 22T, 24T, 25T, 26T, 28T, 30T, 32T, 36T, 38T, 40T, 42T, 44T, 48T, 50T, 60T, 65T, 70T, 72T, 80T (incl. K-Type variants) |
| Bore Diameter Range | 8 mm – 25 mm (0.31" – 0.98") |
| Keyway Width × Height | 3×1.4 mm / 4×1.8 mm / 5×2.3 mm / 6×2.8 mm / 8×3.3 mm (see variant options) |
| Hub Style | Stepped hub with milled keyway |
| Material | Aluminum alloy |
| Quantity per Order | 1 pc |
| Flange | See variant options |
| Outside Diameter | See variant options |
| Hub Length | See variant options |
The tooth count determines your drive ratio. Divide the driven pulley tooth count by the driver pulley tooth count to get the ratio. For example, a 15T driver paired with a 30T driven pulley gives a 2:1 reduction. Smaller tooth counts (15T–20T) are common on motor shafts for speed reduction; larger counts (40T–80T) are used on driven shafts or where higher torque is needed at lower speed.
Match the bore diameter to your motor or gearbox output shaft. Common stepper motor shaft diameters are 5 mm, 6.35 mm (1/4"), 8 mm, 10 mm, and 12 mm. This product offers bores from 8 mm to 25 mm — if your shaft is smaller than 8 mm, this pulley is not suitable. Always verify the shaft diameter with calipers before ordering.
The keyway slot accepts a standard parallel key (sold separately) that fits between the pulley bore and a matching keyway cut into the shaft. This provides positive rotational locking and prevents the pulley from spinning on the shaft under load. For additional axial retention, a set screw through the hub is recommended — check whether your application requires one and tap the hub accordingly if needed.
K-Type variants feature a longer hub extension compared to the standard step hub. The extended hub provides more shaft contact length, which improves stability and torque transfer on longer shaft overhangs or where the pulley must be positioned further from a bearing. Select K-Type when your shaft engagement length is a design constraint.
These pulleys are designed and flanged specifically for 20 mm wide 5M pitch synchronous belts. Using a narrower belt (e.g., 15 mm) may work mechanically but will reduce load capacity and may cause belt tracking issues. Using a wider belt is not recommended as the belt will overhang the tooth face. For other belt widths, please check our other 5M pulley listings.
The pulleys are machined from aluminum alloy, which offers a good strength-to-weight ratio and natural oxidation resistance in typical indoor environments. For applications involving moisture, cutting fluids, or outdoor exposure, consider applying a light coating of corrosion-inhibiting lubricant to the bore and keyway surfaces. Aluminum is not suitable for highly corrosive chemical environments.
Yes. 5M pitch pulleys with keyway bores are commonly used in larger-format 3D printers, laser engravers, and CNC routers where higher torque and belt tension are required compared to smaller GT2 systems. Verify that your belt pitch is 5M (5 mm tooth pitch) and that your belt width is 20 mm before ordering. The keyway design is particularly useful when the pulley must transmit significant torque without slipping.
