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When a stripped or undersized gear brings your CNC router, 3D printer, or custom drive system to a halt, finding a replacement with the exact bore and tooth count is frustrating. This 1.5 Module 65-tooth spur gear is designed for makers, engineers, and hobbyists who need a dimensionally accurate, drop-in mechanical component without custom machining.
Each gear is machined from 45# medium-carbon steel, offering a solid balance of hardness and machinability. The module is 1.5 (Mod 1.5), tooth count is 65T, and the stepped bore ranges from 8 mm (0.31 in) to 25 mm (0.98 in) depending on the variant selected. Teeth thickness options span 12 mm (0.47 in) and 15 mm (0.59 in), with step hub depths of 30 mm, 40 mm, or 50 mm to accommodate different shaft and motor configurations.
Typical use cases include NEMA stepper motor pinion assemblies for DIY CNC machines, rack-and-pinion linear actuators in automation rigs, and gear-reduction drive trains in robotics and custom mechanical projects requiring a 1.5 mod gear ratio stage.
| Module (Mod) | 1.5 |
|---|---|
| Number of Teeth | 65T |
| Material | 45# Medium-Carbon Steel |
| Pressure Angle | 20° |
| Pitch Diameter | 97.5 mm (3.84 in) |
| Outside Diameter (approx.) | 100.5 mm (3.96 in) |
| Teeth Thickness | 12 mm or 15 mm (see variant options) |
| Bore Diameter | 8 mm – 25 mm (see variant options) |
| Step Hub Depth | 30 mm, 40 mm, or 50 mm (see variant options) |
| Finish | Natural machined steel (uncoated) |
| Weight | See variant options |
Measure your motor or drive shaft outer diameter (OD) with calipers. Select the bore variant that matches your shaft OD exactly — for example, if your NEMA 23 motor shaft is 8 mm, choose the 8 mm bore option. If you plan to add a keyway or set screw, choose the bore that matches the shaft before modification.
The Step dimension (e.g., Step 40mm) refers to the total hub depth — the length of the cylindrical boss that extends behind the gear face. A longer step hub provides more shaft engagement and is useful when you need the gear to sit further from a motor face or bearing plate.
Yes. This gear is machined to standard Mod 1.5 involute tooth geometry with a 20° pressure angle, which is the standard for Mod 1.5 gear racks and mating pinions. Always verify that your rack is also Mod 1.5 before assembling.
45# steel spur gears of this size are suited for moderate-to-high torque applications typical of CNC drives, robotics, and automation equipment. Exact load capacity depends on operating speed, lubrication, and duty cycle. For continuous heavy-duty industrial use, consult a mechanical engineer to verify the gear's rated torque for your specific application.
45# carbon steel is not inherently corrosion-resistant. For indoor or dry environments, the natural machined finish is adequate with periodic light oiling. For humid or outdoor environments, apply a rust-inhibiting grease or consider a zinc-phosphate coating after purchase to extend service life.
NEMA 17 motors typically have a 5 mm shaft. This gear's smallest bore option is 8 mm, so it will not directly fit a standard NEMA 17 shaft without a sleeve adapter. It is better suited for NEMA 23 (6.35 mm or 8 mm shaft) and NEMA 34 (12.7 mm shaft) motors, or custom shafts in the 8–25 mm range.
The bore is supplied as a plain finished bore. If your application requires a keyway or radial set screw for positive shaft locking, you will need to machine or drill these features yourself or have them done by a local machine shop. The 45# steel machines cleanly with standard HSS or carbide tooling.
