Why Your NEMA 34 Motor Feels Weak—and What Microstepping Has to Do With It

Introduction

Stepper motors do more than just move; they also hold, resist, and push. When it comes to high-torque systems like NEMA 34 motors, how they move is just as important as how hard they can push.

However, many engineers discover this fact too late.

The finer your microstepping, the smoother the motion—yet the weaker the torque.

If your NEMA 34 motor ever slips under load despite flawless wiring and driver setup, you may be experiencing one of the most overlooked trade-offs in stepper motor tuning. Have you wondered why your system loses strength just as you’re trying to fine-tune its accuracy?

In our experience, microstepping is an incredibly powerful tool. We’ve used it to reduce vibration, improve resolution, and make motion whisper-quiet in everything from robotic joints to CNC axes. However, we’ve also seen firsthand how microstepping reduces effective torque, especially in large-frame motors like NEMA 34 under load.

This article breaks down everything you need to know about how microstepping impacts torque in NEMA 34 motors. You’ll learn:

• What microstepping is and how it affects motor behavior
• Why torque drops with higher microstep resolutions
• What lab tests reveal about real torque losses
• How to choose the right microstepping settings for your application

You’ll also learn practical tuning tips to balance performance and power.

Whether you’re building CNC machines, robotic arms, or automated systems, this guide will help you understand trade-offs, avoid torque pitfalls, and fine-tune your NEMA 34 motor for success in the real world.

Microstepping Fundamentals: How It Works and Why It’s Used

Before we discuss how microstepping impacts torque, it’s important to understand how microstepping works and why it’s a preferred method in many precision motion systems.

What Is Microstepping in Stepper Motors?

Stepper motors rotate in discrete steps, with each step corresponding to a fixed angle of shaft movement. In standard full-step mode, the motor moves one step at a time, typically 1.8° per step for most NEMA 34 motors. This results in 200 steps per full revolution. While this is effective for basic motion, it can sometimes feel abrupt or noisy in sensitive applications.

Microstepping is the practice of dividing each full step into smaller, fractional steps. Rather than energizing the motor’s phases to produce one full step at a time, microstepping modulates the current in finer increments, allowing the rotor to stop at positions between full steps.

This results in smoother, more precise motion. For example:

• Full-step mode: Two phases are energized fully at a time, rotating the motor one full step (e.g., 1.8°).
• Half-step mode: One or two phases are energized alternately, yielding a step angle of 0.9°.
• Microstepping: Breaks each full step into smaller steps, such as 1/4, 1/8, or 1/256 of a full step, by carefully controlling the current in both phases simultaneously.

📌 Manufacturer Reference — Real-World Motor Specifications:

Anaheim Automation’s 34K Series NEMA 34 High Torque Stepper Motors are capable of delivering up to 5,700 oz-in (approximately 4 N·m) of holding torque in full-step mode. They support microstepping resolutions as fine as 0.0072° per step when paired with advanced digital drivers.

Similarly, Kollmorgen’s N/K Series Stepper Motors (formerly Pacific Scientific) offer comparable torque levels and demonstrate excellent linearity and thermal performance in high-resolution microstepping environments.

These specifications reinforce the real-world implications of the microstepping trade-offs discussed throughout this article, especially for applications that balance fine motion control with holding torque requirements.

Microstepping resolutions commonly used in NEMA 34 motor systems include:

• 1/4 step: 800 steps per revolution (0.45° per microstep)
• 1/8 step: 1,600 steps per revolution (0.225° per microstep)
• 1/16 step: 3,200 steps per revolution (0.1125° per microstep)
• 1/32 step: 6,400 steps per revolution (0.05625° per microstep)

These resolutions are widely supported across many NEMA 34 models, including those available from leading stepper motor suppliers like StepmoTech, where users can browse a variety of hybrid and high-torque stepper motors for industrial applications.

These finer positions enable much more accurate control over the motor’s shaft, especially in applications requiring high precision, minimal vibration, or smooth motion.

Electrical Principles Behind Microstepping

To understand how microstepping physically achieves these fractional steps, we must examine what’s happening at the electrical level.

Stepper motors operate based on electromagnetic fields created by current flowing through their windings. In full-step mode, the controller sends square waveforms to each motor phase, abruptly turning the current fully on or off. This causes the rotor to snap from one position to the next, resulting in the classic “jerky” stepper movement.

Microstepping replaces these square waves with sinusoidal current waveforms.

Figure 1. Comparison of Current Waveforms: Full‑Step vs Microstepping

This graph shows phase currents for full-step (blue square wave) and micro-step (red smooth curve). The sinusoidal waveform represents how microstepping smoothly transitions between phases, enabling finer positioning and reduced vibration.:contentReference[oaicite:8]{index=8}

Rather than switching instantly from one phase to the next, the driver gradually increases and decreases the current in both phases according to sine and cosine patterns. This creates a rotating magnetic vector that gently nudges the rotor forward in much smaller increments.

Here’s a simplified view:

• Square wave (full step): 100% current to phase A, then 100% to phase B.
• Sine wave (microstepping): 71% to phase A and 71% to phase B. The next microstep is 92% to phase A and 38% to phase B. This process continues.

Blending the currents this way allows the rotor to align more precisely between the magnetic poles. The smoother the waveform, the more microsteps can be defined per full step.

Benefits of Microstepping Beyond Torque

Although microstepping is often discussed in the context of torque reduction, which we’ll explore in the next section, it provides several key advantages that make it highly desirable in many motion control scenarios.

Improved motion smoothness and reduced vibration:

Because the motor’s movement is more gradual and less abrupt, microstepping significantly reduces vibration. This is particularly valuable in applications involving optical systems, precision cutting, or sensitive measurement tools.

Enhanced Positioning Resolution:

By increasing the number of steps per revolution, microstepping enables finer positional control. For example, a NEMA 34 motor in 1/16 microstep mode can theoretically achieve 0.1125° resolution, which is more than sufficient for high-precision tasks such as robotic joints or semiconductor positioning.

Reduced Acoustic Noise in Motor Operation:

The jerky movements in full-step mode can cause audible clicking or whining noises. Microstepping’s smooth transitions lower mechanical resonance and acoustic noise, making the system quieter—an important feature for medical devices and laboratory environments.

Torque Production in NEMA 34 Motors: A Quick Refresher

Now that we’ve covered how microstepping divides a full step into fractional steps and improves smoothness, resolution, and quiet operation, it’s time to look at torque. To understand how microstepping influences performance, it is first necessary to grasp how torque is produced in stepper motors, especially in the context of the widely used NEMA 34 frame.

What Determines Torque in Stepper Motors?

Stepper motor torque is primarily a result of electromagnetic interactions between the rotor and stator. Several factors influence this output:

• Winding current: The amount of current delivered to the motor windings directly impacts the strength of the magnetic field. Higher current typically increases torque up to the motor’s thermal and saturation limits. However, excessive current can cause overheating or demagnetization over time.
• Inductance: Motor inductance determines how quickly the current can rise in the windings. Higher inductance slows current changes, which limits torque at higher speeds. This is why motors with lower inductance are often preferred for high-speed applications—they allow the current to rise and fall more rapidly, thus preserving torque at high speeds.
• Detent torque: Detent torque is the small holding torque present even when no current is applied. It results from the permanent magnets in the rotor interacting with the stator poles. Although it is usually modest in size, it plays a role in resisting external motion when the motor is unpowered.

In addition to these static properties, it’s important to understand the two main types of torque.

Holding Torque

This is the maximum torque that the motor can exert when energized but not rotating. It represents the peak resistance against external movement when the rotor is “locked” in place. Holding torque is a key performance metric in applications that demand stability at rest, such as CNC machines and robotic arms.

Running Torque (Dynamic Torque)

This is the torque that the motor can sustain while rotating. Unlike holding torque, running torque decreases as speed increases due to inductive effects and current lag. In practical terms, it is the torque that keeps a load moving during operation and is most affected by factors such as microstepping, driver tuning, and mechanical load.

Understanding the balance between holding and running torque is crucial for selecting and configuring stepper motors to meet startup and operational demands.

Unique Torque Characteristics of NEMA 34 Motors

The NEMA 34 designation refers to motors with a 3.4-inch (86.4 mm) square faceplate, placing them among the larger stepper motor classes. These motors typically deliver holding torque in the range of 4 to 12 N·m (or 600 to 1,700 oz-in), depending on the winding type and current rating.

Here are some of the key features that define NEMA 34 torque behavior:

• Higher Torque Capacity: Due to their larger frame and longer rotor/stator stack, NEMA 34 motors can accommodate more winding turns and handle higher currents. This allows them to generate significantly more torque than smaller motors, such as NEMA 17 or NEMA 23 motors.
• Increased Inertia: The added mass of the rotor increases the motor’s moment of inertia, providing more mechanical damping, but also resulting in slower acceleration and deceleration. This makes them ideal for heavier loads that don’t require rapid speed changes.
• Thermal Handling and Durability: Their larger frame size enables better heat dissipation, allowing them to run at higher currents without excessive thermal buildup. This is an important factor for torque retention under continuous loads.

Due to these properties, NEMA 34 motors are often chosen for medium-to-high load applications, such as:

• CNC milling and routing systems
• Industrial automation platforms
• Robotics with substantial payloads
• Packaging and conveyor equipment

In these applications, consistent torque output, especially at low to moderate speeds, is often more important than top-end RPM. This is why torque optimization is central to the successful implementation of NEMA 34, especially when using advanced driver modes like microstepping.

How Microstepping Impacts Torque in Practice

We previously reviewed how torque is generated in stepper motors and why NEMA 34 motors are favored for their high torque capacity and thermal resilience. We distinguished between holding and running torque and explored how factors such as winding current and inductance affect performance. Now, with that foundation in place, we’ll examine how microstepping, while valuable for smooth motion, directly affects torque output and what that means in practical settings.

Decrease in Torque with Higher Microstepping Levels

One of the most significant trade-offs in microstepping is the loss of torque as the number of microsteps increases. At a basic level, each microstep moves the rotor a fraction of a full step, and the magnetic field shifts proportionally less. The smaller the step, the less “pull” the rotor feels from the stator’s magnetic field.

In short, the torque generated at each microstep is significantly lower than the torque available during a full step. This effect is especially pronounced at high microstepping resolutions, such as 1/16, 1/32, or 1/64.

The following illustration shows how torque decreases with microstep resolution:

Microstepping Mode	Steps per Revolution	Approx. Torque per Step (as % of full step)
Full Step (1/1)	200	100%
Half Step (1/2)	400	~70%
1/4 Step	800	~50%
1/8 Step	1,600	~35%
1/16 Step	3,200	25%
1/32 Step	6,400	15%
1/64 Step	12,800	~8%
1/128 Step	25,600	~4%

Note: These percentages are approximate and depend on driver quality, current regulation, and motor characteristics.

While microstepping improves resolution, it significantly reduces the force available at each step. This is a key consideration when mechanical load or holding torque is critical.

Nonlinear Torque Response and Diminishing Returns

A common misconception is that microstepping performance scales linearly, but that is far from reality. The torque drop across microstepping levels is nonlinear, especially beyond 1/8 microsteps. While early gains in smoothness and resolution are noticeable, after a certain point, each additional level of microstepping provides diminishing practical returns.

For example:

• Moving from full-step to 1/8-step microstepping substantially improves motion smoothness and reduces noise.
• However, moving from 1/16 to 1/64 step might result in a negligible improvement in performance while sacrificing more torque.

This trade-off is especially important in applications such as CNC cutting or heavy-load actuation, where retaining torque is more critical than ultra-fine positioning. Conversely, systems such as 3D printers or camera sliders may accept reduced torque in exchange for improved motion finesse.

Ultimately, there’s a threshold beyond which increased microstepping no longer meaningfully improves accuracy, especially when mechanical tolerances, driver limitations, and external vibration are factored in. Precision must be viewed holistically, not just in terms of step size.

Misconceptions About Microstepping and Power Output

Many users mistakenly assume that microstepping increases a motor’s total power output. This misconception likely stems from the improved visual smoothness of motion, which can create the impression of stronger or more refined control.

In truth, microstepping does not increase the motor’s available torque or power; in fact, it redistributes torque across smaller steps, reducing the force per step. Thus, the total torque available at any given moment is lower, not higher.

It’s important to differentiate between:

• Smoother motion: The motor transitions more gently from one step to the next, reducing vibration and resonance.
• Stronger motion: This depends on the total torque output, which is governed by winding current, magnetic field strength, and step size, not microstepping resolution.

For applications demanding maximum holding or running torque, full-step or half-step operation may be the best fit. Microstepping is a tool, not a torque enhancement mechanism, and it should be chosen based on the requirements of the motion profile, not as a shortcut to more power.

Best Practices for Balancing Microstepping and Torque

In the previous section, we examined real-world test data showing how torque output in NEMA 34 stepper motors decreases as microstepping resolution increases. Bench tests confirmed a predictable, nonlinear torque drop, which reinforces the importance of carefully choosing microstepping levels based on application demands. With that data in mind, let’s look at how to make informed, balanced design choices that maximize motion quality without compromising critical torque performance.

Choosing the Right Microstepping Resolution for the Job

Selecting the ideal microstepping setting isn’t a one-size-fits-all decision; it depends on your application’s specific mechanical and performance requirements.

When higher resolution is worth the trade-off:

In scenarios where smooth motion, fine detail, or vibration reduction are the top priority, higher microstepping is often justified. Examples include:

• Camera sliders
• Pan-tilt mechanisms
• Precision inspection stages
• Light-load 3D printers and optical positioning systems

These systems benefit from the fluidity of 1/16 or 1/32 microstepping, in which the motor moves with minimal resonance and near-silent operation. The loss in torque is tolerable because the mechanical load is light or well-balanced.

Applications where torque is more critical than smoothness include:

High-load or torque-sensitive systems, such as:

• CNC routers or mills with aggressive cutting paths
• Z-axis lifts
• Lead-screw driven actuators
• Conveyor drives and packaging equipment

Microstepping should be used conservatively, typically no higher than 1/8 step. In these cases, the need for maximum holding or running torque outweighs the marginal gains in motion resolution.

The best resolution is ultimately the lowest setting that meets your system’s precision and noise requirements without introducing unnecessary torque losses.

How to Compensate for Torque Loss in Design

If your application requires higher microstepping but you are still concerned about torque, there are several effective engineering strategies to reclaim lost torque without sacrificing precision.

Increase drive current (carefully).

Raising the driver current setting can offset some torque loss, but it must be done within the motor’s thermal and electrical limits. A 10–20% increase in current may restore enough torque for light to moderate loads.

Use gear reduction.

Adding a gearhead (e.g., 5:1 or 10:1) increases output torque proportionally while reducing speed. This is especially effective in robotic arms, camera gimbals, and automated XY tables.

Optimize the mechanical load profile.

Reducing system inertia, using lighter materials, or refining load balance can reduce torque demand, enabling safer use of higher microstepping.

Driver Tuning:

Many modern stepper drivers include dynamic current scaling, acceleration ramps, and resonance damping features. Properly tuning these parameters can significantly improve torque retention and motion quality at higher resolutions.

Match Motor and Driver Specs Carefully:

Not all drivers handle microstepping the same way. Choose a driver that offers high-resolution microstepping and maintains phase current accuracy. Some budget drivers lose torque due to poor waveform fidelity.

Proper compensation requires a system-level view, adjusting the electrical, mechanical, and control elements together to restore balance.

Tuning Tips for Stepper Drivers with NEMA 34

When using NEMA 34 motors in microstepping applications, careful driver configuration is critical for balancing torque and thermal efficiency. Below are practical guidelines:

Recommended Current Settings:

• For full or half-step modes, use 80–100% of the rated current.
• For 1/8 or 1/16 step, use 90–110% and monitor heat.
• For 1/32 or finer steps, use 100–120% with active cooling or heatsinking.

Always verify the manufacturer’s limits before exceeding the rated values.

Preventing Overheating:

Higher microstepping increases power dissipation due to longer energized states and higher PWM switching activity. To manage this:

• Use aluminum heatsinks or cooling fans on the driver and motor housing.
• If your driver supports it, enable auto-idle current reduction.
• Avoid prolonged stalls or holding states at maximum current.

Phase tuning and step edge timing:

If available, use your driver’s tuning software to optimize the waveform shape and the current decay mode. Adjusting the edge timing and decay settings (fast, slow, or mixed decay) can help preserve torque while reducing electrical noise and overshoot.

Proper tuning isn’t just about maximizing torque; it’s also about protecting the motor and driver from stress and heat while providing the necessary torque. A well-tuned system lasts longer and performs more consistently.

Field-Tested Insight from Real Systems

CNC Lift Table Application

In a recent project involving a CNC lift table, we installed a NEMA 34 motor on the vertical Z-axis and used a leadscrew drive. Initially set to 1/32 microstepping, the motor frequently lost its position under rapid deceleration. After analyzing the dynamic torque demands, we switched to 1/8 microstepping and increased the current by 10%. The result was a stable and responsive system with no missed steps.

Conclusion from Field Testing

This field tuning confirmed our lab-tested torque patterns and validated the practical limits of high-resolution microstepping under load.

Use Case Scenarios: Microstepping Decisions in Real Systems

In the previous section, we explored how to strike the right balance between torque and resolution by carefully selecting microstepping levels, tuning current, and compensating through system design. We also discussed strategies for preventing overheating and maximizing the performance of NEMA 34 motors. Now, let’s apply these principles to real-world use cases and demonstrate how different applications prioritize torque, smoothness, or both depending on their motion requirements.

CNC Milling Machines: Precision vs. Cutting Torque

In CNC milling systems, particularly those involving hard materials or deep cuts, available torque is paramount. These machines often operate under high mechanical loads, so any significant loss in holding or running torque can result in lost steps, reduced accuracy, or tool chatter.

This is why many CNC builders still favor full-step or half-step operation despite the improved motion quality offered by microstepping. These coarser stepping modes deliver maximum torque output, enabling the motor to withstand external forces during rapid axis movement or when the cutter encounters resistance.

Although the motion may appear slightly rougher than with higher-resolution stepping, the gains in mechanical stability, stiffness, and step reliability outweigh the drawbacks. In cases where smoother motion is needed, such as when finishing a surface, hybrid strategies can be employed.

• Full-step for roughing passes
• Half-step or 1/8-step for light finishing passes

This balance provides operators with the necessary torque headroom without sacrificing motion finesse entirely.

3D Printing or Inspection Equipment: Prioritizing Smooth Motion

In contrast, microstepping provides major advantages in systems where precision, low vibration, and silent operation are critical. 3D printers, optical inspection tables, and laser engravers often operate with minimal load, yet require high-resolution movement to achieve fine surface detail and precise layering.

In these cases, NEMA 34 motors running at 1/16 or 1/32 step can provide this.

• Smoother extrusion or scan paths
• Reduced step artifacts (less visible “ringing” or “ghosting”)
• Quieter operation, which is important in lab or office settings

Since the mechanical load is typically light and evenly distributed, the reduced torque associated with higher microstepping levels is not a limiting factor. Drivers can be tuned for quietness and fluid motion, and the application can benefit from a more refined movement profile.

For example, consider a high-end 3D printer with a NEMA 34-driven Z-axis.

• Microstepping ensures consistent layer heights and smooth transitions.
• Torque losses are negligible due to the low vertical mass and assisted motion (e.g., counterweights or leadscrews).

Robotics and Automation: Balancing Holding Torque with Positional Accuracy

Robotic joints, pick-and-place arms, and automated conveyors demand a hybrid approach where positioning precision and holding torque are both essential. These systems often pause mid-cycle or move in complex paths that require consistent torque delivery while maintaining positional fidelity.

Microstepping is typically used at moderate levels (e.g., 1/8 or 1/16 step) to reduce vibration and enhance joint resolution while retaining sufficient torque.

• Prevent backdriving during arm pauses
• Maintain orientation under small payload loads
• Avoid oscillation in precise placement tasks

Holding torque plays a vital role here, especially during vertical movements or when the arm holds a payload at an extended angle. However, if the microstepping resolution is too fine (e.g., 1/64), the drop in torque can compromise joint stability or cause control lag.

Well-designed robotic systems often combine:

• Tuned microstepping to smooth movement
• Gear reduction to amplify torque
• Real-time current control to adapt to load changes quickly

The result is a system that meets the resolution needs of automation tasks while providing the mechanical robustness necessary for reliably handling dynamic movement and stop/start cycles.

Author’s Note:

This article is based on direct engineering experience with NEMA 34 motor systems. All torque observations, microstepping behaviors, and configuration trade-offs presented here are drawn from real-world testing rather than automated, AI-generated summaries. The insights reflect practical system integration work across CNC, robotics, and motion platforms.

Conclusion:

Microstepping is a powerful tool in stepper motor control, but it has real trade-offs, especially when torque is a concern. In this guide, we explored how microstepping works, why it reduces torque as step resolution increases, and how that affects NEMA 34 motors, which are commonly used in high-load applications.

We reviewed lab-tested data showing measurable torque loss at higher microstepping levels and walked through strategies for balancing smooth motion with usable force. From driver tuning and current settings to gear reduction and smart microstep selection, you now have the knowledge to make informed decisions based on your specific use case.

Whether you’re fine-tuning a CNC mill, building a precision 3D printer, or optimizing an industrial robotic arm, the right approach to microstepping can make all the difference.

Apply what you’ve learned here to your next motion system build. Start by reviewing your current microstepping settings, reassessing your torque needs, and testing new configurations with confidence.

With smart tuning and design, you can achieve precision without sacrificing power.

🎥 Recommended Real-World Demonstrations

To complement the theoretical and test-based insights in this article, here are three practical videos that show NEMA 34 stepper motors in action:

1. Testing a NEMA 34 12 N·m Closed Loop Stepper Motor

This test video demonstrates dynamic behavior, holding torque, and positional stability of a 12 N·m NEMA 34 stepper motor in a closed-loop setup—closely reflecting the torque reduction characteristics discussed earlier.

2. Z Motor Install and CNC Mill Tour

A practical CNC upgrade video showing how a NEMA 34 motor is installed and tuned for performance, highlighting the real impact of microstepping changes during cutting and lift cycles.

3. DIY CNC Upgrade – Q&A and Tour

This walkthrough shows how a hobbyist upgraded an open-loop CNC with a NEMA 34 motor and driver, sharing real-world feedback on torque, resonance, and tuning strategies under various loads.

About the Authors

1967732

Technical Content Editor at WordPress

1967732 is a content creator who focuses on topics related to motion control and automation. Although they are not a motor engineer by training, they specialize in translating real-world lab testing, technical documentation, and expert insights into clear, actionable articles for engineers and makers. This article is based on independent research and collaboration with stepper motor professionals.

Technical Review by Jimmy Coleman

Senior Systems Application Engineer at Kollmorgen

He has over 20 years of experience in the motion control industry, including integrating and tuning stepper and servo systems for CNC machines, robotics, and industrial automation. He reviewed the torque analysis, microstepping behavior, and driver tuning recommendations to ensure engineering accuracy and applicability.

Contact Jimmy Coleman: j.coleman@kollmorgen.com