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When your CNC router, 3D printer, or automation rig demands slip-free, low-backlash power transmission, a mismatched or worn pulley becomes the weakest link in the entire drive train. Engineers and makers who work with 3M pitch synchronous belts need a pulley that holds tight tolerances on tooth profile and bore concentricity — every time. These 3M Timing Belt Pulleys in AF-Type configuration are designed for exactly that demand.
Each pulley is machined from aluminum alloy, offering a balance of light weight and structural rigidity. The AF-Type flange design keeps the belt tracking reliably on the pulley face. Available in three tooth counts — 40T, 45T, and 48T — with bore diameters ranging from 5 mm (0.20 in) to 25 mm (0.98 in), and a fixed applicable belt width of 15 mm (0.59 in). Keyway bore options (e.g., 8mm 3×1.4mm, 10mm 4×1.8mm, 12mm 5×2.3mm) are available for shaft-locking applications.
Typical use cases include desktop CNC milling machines requiring 3M synchronous drive pulleys with AF-type flanges, RepRap-style 3D printers upgrading to wider 15mm belt systems, and light industrial conveyor or indexing table builds where a 40-tooth or 48-tooth 3M pulley with a specific bore-to-shaft fit is critical.
| Belt Pitch | 3M (3 mm) |
|---|---|
| Pulley Type | AF-Type (double-flanged) |
| Number of Teeth | 40T / 45T / 48T (see variant options) |
| Applicable Belt Width | 15 mm (0.59 in) |
| Bore Diameter | 5 mm – 25 mm (see variant options) |
| Keyway Bore Options | 8mm (3×1.4mm), 10mm (4×1.8mm), 12mm (4×1.8mm / 5×2.3mm), 12.7mm (5×2.3mm), 14mm (5×2.3mm), 15mm (5×2.3mm), 19mm (5×2.3mm) |
| Material | Aluminum alloy |
| Flange Configuration | Double-flanged (AF-Type) |
| Weight | See variant options |
| Surface Finish | See variant options |
The tooth count determines your drive ratio and pitch diameter. A 40T pulley has a smaller pitch diameter than a 48T, so it produces a higher belt speed for the same shaft RPM when paired with a smaller driven pulley. Choose 40T for compact, faster-moving axes; 45T or 48T for slightly larger pitch diameters or when you need a specific gear ratio with your driven pulley. Calculate pitch diameter as: PD = (Teeth × Pitch) ÷ π.
Measure your motor or drive shaft diameter precisely with calipers. Select the bore that matches your shaft — a bore that is too large will cause runout and vibration. For shafts requiring positive locking, choose a keyway bore variant (e.g., 8mm 3×1.4mm) that matches your shaft's keyway dimensions. Standard round bores are typically secured with a set screw.
These pulleys are machined to the standard 3M pitch tooth profile (3 mm pitch, trapezoidal tooth form), so they are compatible with any 3M synchronous timing belt from any manufacturer that conforms to the 3M standard. Confirm your belt is 15 mm wide to match the applicable belt width of this pulley.
Aluminum alloy pulleys are well-suited for light-to-medium duty motion control applications such as 3D printers, CNC routers, laser cutters, and small conveyor systems. For heavy industrial loads with high shock or continuous high-torque operation, contact us to confirm suitability. The AF-type flanges add lateral belt retention, which reduces edge wear under moderate side loads.
Yes. The AF-Type designation means the pulley has flanges on both sides of the belt contact face. These flanges act as guides that keep the 15 mm belt centered on the pulley, preventing it from walking off the edge during operation — particularly important in vertical or angled drive configurations.
Keyway dimensions are listed in the variant name in the format: bore diameter (key width × key depth), e.g., "12mm (5×2.3mm)" means a 12 mm bore with a 5 mm wide × 2.3 mm deep keyway. Measure your shaft's keyway with a caliper or refer to your motor's datasheet. The key and keyway must match for a proper interference-free fit.
Yes. These pulleys can be used on either the driving (motor) shaft or the driven (load) shaft. When used as a pair, the ratio of teeth between the two pulleys determines your speed and torque multiplication. Ensure both pulleys share the same 3M pitch and that the belt width matches the 15 mm specification of both pulleys.
