NEMA 17 42-48 Stepper Motor, 0.9° – 1.7 A – 5 mm D Shaft

Bipolar hybrid 0.9° NEMA 17 stepper motor, reference 42HS48-0.9 / 17HS8401S-09, with a 48 mm body and 5 mm D shaft. It provides 400 full steps per revolution and a declared minimum holding torque of 52 N·cm, offering a balanced combination for 3D-printer, CNC, laser, plotter and custom mechanism axes.

The 0.9° step angle doubles nominal angular command resolution compared with 1.8°, but does not guarantee twice the final accuracy: backlash, flex, microstepping, load and missed steps still affect motion.

Nominal specifications

Dimensions

• Face: 42.3 mm maximum.
• Body: 48 mm.
• Pattern: 31 ±0.1 mm; 4 × M3, 4 mm minimum depth.
• Pilot: Ø22 × 2 mm.
• Shaft: Ø5 × 24 ±0.5 mm, D profile.
• Approximately 1 m detachable cable included.

Installation and firmware

Use a current-regulated bipolar driver. With a configurable TMC, 0.8-1.0 A RMS is a cautious starting range; increase only after checking load, missed steps and temperatures. There is no universal VREF for A4988 or DRV8825 modules. Identify coil pairs by continuity and never connect the motor while the driver is powered.

• Marlin: use DEFAULT_AXIS_STEPS_PER_UNIT or M92. At 16 microsteps: GT2 20T = 160 steps/mm; TR8×8 = 800 steps/mm.
• Klipper: set full_steps_per_rotation: 400; use rotation_distance: 40 for GT2 20T or 8 for TR8×8 without reduction.
• RepRapFirmware: use M92 for steps/mm and M906 for current when supported by the driver.

Always confirm the transmission, microsteps and gearing. Replacing a 1.8° motor with all other factors unchanged doubles steps/mm and the required step-pulse frequency at the same speed.

Compatibility and comparison

It is not a universal replacement merely because it is NEMA 17. Space for the 48 mm body, shaft, pattern, current, torque, connector, pinout and configuration must all match. Compare it with the more compact 0.9° 42-40 and the higher-static-torque 0.9° 42-60.

It is for you if

• You want a balance of size, mass and torque.
• You need 400 full steps/rev and can configure the firmware.
• Your mount accepts a 48 mm body and 5 mm D shaft.

It is not for you if

• You need a drop-in replacement without checking wiring and current.
• The moving axis needs the lowest possible mass.
• Your application requires a certified torque curve at a specific speed.

Dimension-dependent accessories include the NEMA 17 bracket, 20T GT2 pulley for a 5 mm shaft and configurable TMC2209 driver.

Contents: 1 motor and an approximately 1 m cable. Other accessories are not included.