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When your motion system slips, skips, or loses steps, the culprit is often an undersized or poorly machined synchronous pulley. Engineers, makers, and 3D printer builders who demand repeatable, backlash-free motion need a timing pulley that holds tolerance across thousands of cycles — not one that wears out after a few weeks of continuous use.
These S2M timing pulleys are machined from aluminum alloy with an anodized finish, covering tooth counts from 28T to 50T and a 10mm belt width (S2M pitch: 2mm). Bore options span 4mm to 15mm (approximately 0.157" to 0.591"), including metric keyway variants (3mm and 4mm keyways) and imperial 6.35mm / 12.7mm bores for compatibility with North American motor shafts. Hub flange width is approximately 11mm.
Typical use cases include FDM 3D printer X/Y axis drives (S2M-28T to S2M-40T range), compact CNC router feed axes, robotic arm joint actuators, and light-duty conveyor synchronization systems where a 2mm pitch belt provides the right balance of speed and torque transmission.
Available in 14 sizes from 28T to 50T (28, 30, 32, 34, 35, 36, 38, 40, 42, 44, 45, 46, 48, 50 teeth), covering a broad gear ratio selection for single-stage drive design.
Bore options from 4mm to 15mm including 6.35mm and 12.7mm imperial sizes. Keyway variants (3mm and 4mm) available for positive shaft locking without set-screw slip.
Machined aluminum body keeps rotating mass low — critical for 3D printer acceleration performance and responsive CNC axis movement.
2mm pitch tooth profile conforms to S2M belt standard. Hub flange width approximately 11mm keeps the belt tracked without additional guides on most applications.
Plain bore variants include a set screw for shaft retention. Keyway variants provide additional torque capacity for higher-load drive stages.
Tooth geometry and bore range match common NEMA 17 / NEMA 23 motor shaft diameters (5mm, 6.35mm, 8mm), making these a direct fit for CoreXY, Cartesian, and delta printer architectures.
| Belt Standard | S2M (2mm pitch) |
|---|---|
| Belt Width | 10mm |
| Tooth Count | 28T / 30T / 32T / 34T / 35T / 36T / 38T / 40T / 42T / 44T / 45T / 46T / 48T / 50T |
| Bore Diameter | 4 / 5 / 6 / 6.35 / 8 / 10 / 12 / 12.7 / 14 / 15mm (see variant options) |
| Keyway Options | 3mm keyway (8mm, 10mm bore) / 4mm keyway (10mm, 12mm bore) / 5mm keyway (12.7mm, 14mm, 15mm bore) |
| Hub Flange Width | Approximately 11mm |
| Material | Aluminum alloy |
| Finish | Anodized (natural / silver) |
| Pitch Diameter (28T) | Approximately 17.83mm (0.702") |
| Pitch Diameter (50T) | Approximately 31.83mm (1.253") |
| Weight | See variant options |
| Quantity | 1 piece per order |
Tooth count determines your drive ratio and pitch diameter. A smaller pulley (e.g., 28T) on the motor paired with a larger pulley on the driven shaft reduces speed and increases torque. For 3D printers, 20T–40T on the motor is typical; this 28–50T range suits both motor-side and idler/driven-side roles. Calculate pitch diameter as: PD = (Teeth × Pitch) / π. For S2M: PD(mm) = Teeth × 2 / π.
Standard NEMA 17 motors have a 5mm output shaft. Select the 5mm bore variant. If your motor has a D-cut shaft, the set screw in the plain bore variant will engage the flat. For NEMA 23 motors, the shaft is typically 6.35mm (1/4") — select the 6.35mm bore variant.
For light-duty applications like 3D printer axes, a set screw on a plain bore is generally sufficient. For higher-torque applications — CNC feed drives, conveyor systems, or any axis subject to reversing loads — a keyway variant provides positive mechanical engagement and prevents rotational slip under load spikes.
No. S2M and GT2 both use a 2mm pitch, but the tooth profile geometry differs. S2M uses a trapezoidal tooth form while GT2 uses a curvilinear profile. Mixing S2M pulleys with GT2 belts (or vice versa) will cause accelerated belt wear and potential skipping. Always match pulley and belt to the same standard.
The aluminum alloy body with anodized finish provides good resistance to oxidation and light moisture exposure, suitable for indoor workshop and printer enclosure environments. These pulleys are not rated for continuous outdoor exposure or chemically aggressive environments. For such conditions, consider stainless steel alternatives.
For a two-pulley open drive: Belt Length ≈ 2C + π(D₁ + D₂)/2 + (D₁ − D₂)²/(4C), where C is center distance and D₁, D₂ are pitch diameters. For closed-loop (toothed) belts, the tooth count must be a whole number. Use an online belt length calculator with S2M parameters, or contact us with your center distance and pulley sizes for a recommendation.
These pulleys are designed as driven or driving pulleys with a through-bore for shaft mounting. They are not configured as flanged idlers with bearings. If you need a belt idler, you would need to mount this pulley on a shaft with appropriate bearings. Smooth-face idler pulleys are a separate product category.
