Designing and Building an Axial Flux Motor

What Is an Axial Flux Motor (and Why Build One)?

Most electric motors you see are radial flux motors - a cylinder inside a cylinder.

An axial flux motor is different: it’s more like a disc facing another disc, with magnetic fields flowing parallel to the shaft instead of radially outward.

Axial flux motors can achieve:

1. Higher torque density
2. Shorter axial length
3. Better use of magnetic material

So why aren’t they everywhere?

They’re hard to make, especially the stator laminations.

Because of this reason, you might only really see these motors in high performance electric vehicles.

I built this motor as a personal challenge in the couple of days where I didn't have class but also hadn't left campus yet for Christmas break. I also wanted to actually test it on a dynamometer and see how it performed in the real world.

This Instructable walks through the full build: the slot/pole choices, rotor + magnet layout, hand-laminated stator, coil winding, CNC machining, wiring, control setup, and the testing. I’ll also include what went wrong and what I’d change for a version two.

I recognize that most people don't have access to the manufacturing facilities that I do, so I will also detail how to make a 3D printable axial flux motor.

What You’ll Learn

This Instructable is designed to be both a hands-on build and a guided explanation of how brushless motors actually work. Even if you don’t plan to build this exact motor, you should walk away understanding why motors are designed the way they are.

By the end, you’ll understand:

1. How electric motors work at a fundamental level
2. The difference between radial flux and axial flux motors
3. What poles, slots, and winding factor actually mean
4. Why motors use steel cores (and why lamination matters
5. How to design and wind motor coils by hand
6. How brushless motor control works (without hand-waving)
7. How motors are tested in the real world
8. Common failure modes in DIY motors

This project can be built in two different ways, depending on what tools and facilities you have access to:

1. Version A: Machined axial flux motor (aluminum + steel, higher performance)
2. Version B: Fully 3D-printable axial flux motor (lower performance, much more accessible)

A good CAD software is critical

1. Fusion 360 was used for both design and manufacturing, including CNC work.

Core Components (Both Versions)

These are required no matter how you build it.

1. Neodymium magnets
2. Rectangular or square magnets work best
3. (Exact size is flexible; layout matters more than dimensions)
4. Magnet wire
5. Round or square magnet wire.
6. ~18–14 AWG range works well for hand winding
7. Epoxy (high strength & high temperature)
8. Used for:
9. Magnet retention
10. Stator lamination (metal version)
11. Structural bonding
12. High-temperature epoxy is strongly recommended
13. You can get away with just super glue for the plastic version.
14. Motor shaft
15. Steel shaft sized for your bearings
16. Shoulder bolt is the easiest.
17. You can also machine your own.
18. Bearings (2x minimum)
19. Radial ball bearings
20. Needle roller bearings + Thrust bearings
21. Fasteners
22. M3 to M5 range
23. Kapton tape or electrical insulation
24. Solder + soldering iron

Electronics & Control (Both Versions)

1. Brushless motor controller (ESC or VESC)
2. Hobby ESCs work for the 3D printed version
3. VESC recommended for proper FOC control
4. Servo Tester
5. Generates a PWM pulse to control the motor controllers
6. DC power supply or battery
7. 12–48 V depending on controller
8. Current capability matters more than voltage
9. Oscilloscope (optional but very helpful)
10. Useful for:
11. Viewing back-EMF
12. Debugging phase connections

Tools (Minimum Set)

These are realistic for most makerspaces.

1. Hex keys / screwdrivers
2. Calipers (very important)
3. Wire strippers
4. Flush cutters
5. Utility knife or razor blade

Version A: Machined / Metal Motor (Higher Performance)

Only required if you want to build the metal stator + aluminum rotor version.

Materials

1. Aluminum plate or billet (rotor + housing)
2. Electrical steel sheet (for stator laminations)

Tools

1. CNC mill or manual mill
2. Laser cutter or waterjet (for stator laminations)
3. Drill press
4. Arbor press (for bearings)

What I Used Specifically

1. 14 AWG square magnet wire (mwswire.com)
2. 0.5mm Silicone Steel sheets
3. 0.5" Aluminum Stock
4. 0.125" Aluminum Stock
5. 12x 0.75" x 0.5" x 1/16" N52 Magnet
6. 12x 0.5" x 0.5" x 1/16" N52 Magnet
7. 2x 6705 Bearings

Version B: 3D-Printable Motor (Accessible Version)

This version is designed so almost anyone can try it.

Materials

1. 3D printer (PLA works, PETG or Nylon preferred)
2. Printed stator housing
3. Printed rotor disc
4. Printed coil winding jig

What I Used Specifically

1. 18 AWG magnet wire
2. 1x 5/8" Steel shoulder bolt
3. 1x 5/8" Needle roller bearing
4. 1x 5/8" Thrust bearing
5. 2x 5/8" Thrust bearing washer
6. 1x 5/8" Shaft collar
7. 12x 20mm x 10mm x 5mm N52 Magnet

Notes

1. Lower efficiency and torque than the metal version
2. Much easier to assemble
3. Excellent for learning how motors work
4. Safer for beginners

I’ll include printable files and recommended print settings later in the Instructable.

Optional but Highly Recommended

1. Force Sensor (for Prony Brake setup)
2. Dynamometer (or DIY brake test)
3. Tachometer

Safety Note

Axial flux motors can spin fast and can be dangerous.

Magnets can:

1. Snap together unexpectedly
2. Fly off at high RPM
3. Pull bearings out of housings

Always:

1. Wear eye protection
2. Stand clear during first spin-up

Before building an axial flux motor, it’s worth understanding what a motor really is.

At the most basic level, a motor converts electrical energy into mechanical rotation using magnetic forces. Everything else - brushless control, steel cores, laminations - is just engineering layered on top of that idea.

Let's break it down.

1. Current Creates a Magnetic Field

If you pass current through a wire, it creates a magnetic field around it.

This isn’t a metaphor — it’s a physical field you can measure.

1. Direction of current -> direction of magnetic field
2. More current -> stronger field

When you wrap that wire into a coil, the magnetic field becomes much stronger and more concentrated.

This is the basis of electromagnets.

2. Magnetic Fields Create Force

When a current-carrying wire sits inside a magnetic field, it experiences a force.

That force:

1. Is perpendicular to both the current and the magnetic field
2. Can push or pull the wire

3. Turning Force into Rotation

To make rotation, we:

1. Arrange wires into coils
2. Place permanent magnets nearby
3. Energize coils in a sequence

As the magnetic fields interact, the coils continuously pull and push in a way that creates torque around a shaft.

If you keep switching which coils are energized at the right time, the motor keeps spinning.

4. Why Motors Use Steel Cores

You might wonder:

Why do motors have steel inside of them?

Steel acts like a magnetic amplifier:

1. An external magnetic field aligns the domains inside of the steel, effectively making it a magnet itself, albeit only temporarily
2. It increases the strength of the field in this way
3. Which means it allows much higher torque for the same current

However, steel saturates, AKA all the magnetic domains are aligned. Once it’s saturated, adding more current doesn’t help much - an important limitation in motor design.

5. Why Steel Is Laminated

When magnetic fields change over time (as they do in motors), solid steel develops eddy currents - circulating currents that:

1. Waste energy
2. Turn power into heat
3. Reduce efficiency

By slicing the steel into thin layers (laminations) and insulating them from each other, these currents are broken up.

That’s why nearly all high-performance motors use laminated cores.

6. Brushless Motors and Timing

In a brushed motor, physical brushes switch current for you, acting almost like switches.

In a brushless motor, like the Axial Flux motor or a drone motor, the electronics do the switching for you.

Later in this Instructable, I’ll show how this switching is handled using Field-Oriented Control (FOC).

Why This Matters for Axial Flux Motors

Axial flux motors use the same physics. The magnets and coils are just arranged differently.

Understanding:

1. Where magnetic fields flow
2. How torque is generated
3. Why steel and copper are used

…makes every design decision in later steps make some sort of sense.

The most common brushless motors are radial flux motors. Think drone motors.

In a radial flux motor:

1. The rotor and stator are arranged like a cylinder inside a cylinder
2. Magnetic flux flows radially outward from the shaft

This design is popular because it’s:

1. Easy to manufacture
2. Mechanically forgiving
3. Simple to support with bearings

That’s why radial flux motors dominate everyday applications.

An axial flux motor uses the same physics, but a different geometry.

In an axial flux motor:

1. The rotor and stator face each other like flat discs
2. Magnetic flux flows parallel to the shaft
3. Torque is produced farther from the center

You can think of it as:

1. Two discs trying to twist each other

Why Axial Flux Motors Are Interesting

Axial flux motors can achieve:

1. Higher torque density
2. Thinner shape
3. Lower amount of steel needed

This makes them attractive for high-performance applications.

Why They’re Hard to Build

Axial flux motors also come with challenges:

1. Flat stator laminations are difficult to manufacture
2. Strong axial magnetic forces stress bearings
3. Air gap and parallelism tolerances matter a lot

Because of this, axial flux motors are usually found in high-end or low-volume designs, like performance EVs.

For this project, I used a single-rotor, single-stator axial flux design to keep things simple. Later, I’ll explain how a double-rotor version would improve performance.

Before designing the motor, we need to choose how many magnets and how many coils it will have.

1. Poles are the magnets on the rotor
2. Slots are where the coils sit in the stator

These numbers control how smooth the motor runs and how hard it is to build.

Why the Numbers Matter

1. Too few poles or slots → strong “clicking” (cogging torque)
2. More poles and slots → smoother torque, but harder to manufacture
3. Some combinations use magnetic fields more efficiently than others

Rather than guessing, motor designers use known good slot/pole combinations.

My Choice: 9 Slots, 12 Poles

I chose 9 stator slots and 12 rotor poles because:

1. It has a good winding factor
2. Torque is reasonably smooth
3. It keeps the stator simpler to machine and laminate

A 12-slot version would perform slightly better, but the added complexity wasn’t worth it for a hand-built motor.

Once you choose slot and pole count, the rest of the motor geometry is mostly locked in.

bavaria-direct.co.za

You can play around with slots and poles with this calculator. The closer the winding factor is to 1, the more efficiently the coils work. The higher the cogging steps the less clicking behavior there will be.

With the slot and pole count chosen, the next step is designing the rotor - specifically, how the magnets are arranged.

Starting With the Magnets

Instead of designing the motor first and buying magnets later, I did the opposite. I already had the magnets on hand, so their size and shape set the scale of the entire motor.

The magnets I used were:

1. Rectangular and square
2. 1/16” thick
3. Arranged to approximate a triangular wedge shape

That wedge shape was then patterned in a circle to create the full rotor.

Why Magnet Shape and Placement Matter

The goal is to:

1. Maximize magnetic interaction with the stator coils
2. Keep the magnetic field as uniform as possible
3. Avoid wasting magnet material

Placing the magnets farther from the center also increases torque, since torque scales with radius.

Back Iron (Very Important)

Behind the magnets, I added a steel back iron.

The back iron:

1. Prevents magnetic flux from leaking out the back of the rotor
2. Forces more flux through the stator coils
3. Significantly improves torque

The rest of the rotor is aluminum, since it’s easier to machine and doesn’t need to carry magnetic flux. It also helps with thermals a little bit, since heat would radiate from the coils and often ends up in the rotor.

At this point, the rotor diameter, shaft size, and magnet layout are fixed. Everything else - stator size, air gap, and bearing placement - now has to work around this geometry.

With the rotor defined, the next step is designing the stator - the part that holds the coils and shapes the magnetic field.

Steel vs Copper (The Core Tradeoff)

In a motor, you’re always balancing:

1. Copper -> produces magnetic field
2. Steel -> guides and amplifies that field

Too much steel wastes space.

Too much copper starves the magnetic path.

For this motor, I targeted a copper-to-steel ratio similar to commercial motors (roughly ~30% copper by area).

Coil Choice

I used square magnet wire, which packs more efficiently than round wire. This lets more copper fit into each slot, increasing torque for the same stator size.

The coils were sized so they:

1. Fit cleanly into the stator slots
2. Could realistically be wound by hand
3. Left tolerance for imperfect lamination

Hand-built motors need a healthy amount of tolerance to actually come together at the end.

Air Gap and Tolerances

The air gap between rotor and stator is critical:

1. Smaller air gap -> more torque
2. Larger air gap -> more tolerance and safety

Because this motor was laminated and wound by hand, I intentionally left extra clearance at the cost of performance.

Why the Stator Is Laminated

The stator is made from thin steel laminations instead of solid steel.

Laminations:

1. Reduce eddy current losses
2. Improve efficiency at higher speeds
3. Are essential for real motor performance

I’ll cover how these laminations were made and assembled in the next step.

At this point, the motor’s electromagnetic geometry is fully defined. What’s left is turning these shapes into real parts.

With the stator design finalized, it’s time to turn it into a real part.

Cutting the Laminations

The stator core is made from thin steel laminations rather than solid steel. Each lamination was:

1. Laser cut from ~0.5 mm electrical steel
2. Identical in shape
3. Stacked to form the full stator thickness

Thin laminations reduce eddy current losses and improve efficiency.

Hand Laminating the Stator

Since this was a one-off build, the laminations were:

1. Aligned by hand
2. Epoxied together (3M DP420 epoxy)
3. Pressed flat while curing

This process isn’t perfect, which is why extra tolerance was designed into the air gap earlier. It's important to note that the laminations go out radially from the center of the stator, as if they were stacked vertically, they don't have the benefit of reducing eddy current losses at all.

Note on the 3D-Printable Version

The 3D-printed version of this motor does not use steel laminations.

In that version:

1. The stator is plastic
2. The coils are air-cored
3. There is no changing magnetic field inside steel

Because there’s no steel, there are no eddy currents to worry about, so laminations aren’t needed. The tradeoff is much lower torque and efficiency - but far easier manufacturing and much safer experimentation.

The stator housing does more than just hold parts together - it sets the air gap, bearing alignment, and overall rigidity of the motor. Small errors here show up immediately at speed, which is why I took a lot of time machining this part.

I started with a chunk of aluminum stock and cut it down to the rough size to fit in the CNC machine.

CAM and CNC Machining

The housing was machined on a Carvera Air desktop CNC mill.

The workflow was:

1. Model the housing in Fusion 360
2. Create CAM toolpaths in Fusion 360
3. I used a very small end mill and very small stepovers to be as precise as possible.
4. Mount the stock in the CNC
5. Machine all features in a single setup where possible

Using a desktop CNC made it easier to get those tight tolerances since the tool was much smaller and I was forced to be precise. The part took 4 hours to machine.

Learning CAM and CNC is its own beast, so I won't get into it in this Instructable. Here's a good video on it though: Fusion 360 Tutorial | CAM Basics

Bearing Bores (Very Important)

The bearing bores were:

1. Machined slightly undersize
2. Sneak-fit in small increments
3. Checked frequently with the actual bearings

This allowed me to achieve a solid press fit, which is critical. In axial flux motors, magnetic forces actively try to pull the rotor into the stator - loose bearings will pop out.

Bearing Layout

I used two deep-groove ball bearings, stacked axially.

This isn’t ideal for handling axial loads, but it worked well enough for testing using parts I already had. A better long-term design would include:

1. Controlled preload
2. Thrust or angular contact bearings

I’ll talk more about this in the “What I’d Change” section.

With the stator structure complete, it’s time to add the part that actually generates torque: the coils.

Winding the Coils

The coils were wound by hand using a simple 3D-printed winding jig. This keeps the coils consistent in shape and makes installation much easier.

Key points:

1. Square magnet wire was used to maximize copper packing
2. Each coil was wound with the same number of turns (8 turns)
3. Tension was kept consistent to avoid loose windings

Hand winding isn’t fast, but it works well for one-off motors.

Test-Fitting Before Final Assembly

Before committing anything permanently:

1. The coils were test-fit into a plastic stator mockup
2. Clearances were checked
3. Any tight spots were corrected

This prevents damaging the enamel (the protective coating on magnet wire) when installing coils into the real stator.

Installing the Coils

Once satisfied with the fit:

1. Coils were inserted into the laminated stator
2. Kapton tape was added where needed to prevent shorts
3. Leads were routed carefully to avoid rubbing or pinching

Because tolerances stack up in hand-built parts, insulation here is critical.

Sanding down the enamel

When all coils were wound, I went ahead with sanding off enamel at the end of the coils. This allows for soldering to be possible later on. This can either be done with sandpaper or carefully with a dremel.

Wiring the Coils Into Phases

This motor uses a 3-phase BLDC configuration.

1. Each phase is made by connecting multiple coils in series
2. The three phases are electrically identical, just offset in space
3. Exact phase order doesn’t matter yet — it can be swapped later in software

I wired the motor in a star (Y/wye) configuration, which:

1. Reduces current for a given torque
2. Is more forgiving for initial testing

(Delta wiring is possible, but less beginner-friendly.)

Machining the Rotor

The rotor was machined from aluminum on a Carvera Air desktop CNC mill.

Process:

1. Cut aluminum stock to size
2. Fixture it in the CNC
3. Generate CAM toolpaths in Fusion 360
4. Machine the outer profile, center bore, and back-iron pocket

Aluminum was chosen because it’s non-magnetic and easy to machine.

Epoxying the Back Iron

The steel back iron was laser cut earlier along with the stator laminations.

1. The back iron was epoxied into the recessed pocket in the rotor
2. Care was taken to keep it flat and fully seated
3. The epoxy was allowed to cure completely before installing magnets

The back iron prevents flux from leaking out the back of the rotor and significantly improves torque.

Epoxying the Magnets (With an Alignment Jig)

The rotor magnets were installed using high-strength epoxy and a 3D-printed alignment jig.

The jig:

1. Sets the angular position of each magnet
2. Keeps spacing consistent
3. Prevents magnets from snapping together during assembly

Installation steps:

1. Apply epoxy to the magnet pockets
2. Place magnets with alternating north/south orientation
3. Use the printed jig to hold everything in place
4. Allow full cure before handling
5. After full cure use flush cutters to remove the jig

Machining the Shaft

The shaft was machined on a CNC mill to set the main geometry of the hole pattern, then cleaned up on a lathe.

This allowed:

1. Fine adjustment of bearing diameters
2. Smooth surface finish
3. Controlled press-fit tolerances

Bearings were test-fit frequently to sneak up on the correct size.

Machining a Mounting Plate

It's important to mount the motor securely to the table while testing. To be able to do this a mounting plate can be machined and the motor then mounted to it.

Epoxying the Stator Core into the Housing

Before installing bearings or the rotor, the laminated silicon steel stator needs to be fixed into the housing.

Process:

1. The laminated stator stack was test-fit into the aluminum housing
2. Epoxy was applied evenly on the bottom of the stator piece
3. The stator was pressed fully into place and aligned
4. Excess epoxy was cleaned up
5. The assembly was allowed to fully cure

Once cured, the steel part of the stator behaves like a single solid part of the housing.

Pressing in the Bearings

1. Bearings were press-fit into the housing

Axial flux motors see large axial magnetic forces - a loose bearing will pop out.

Installing the Shaft

1. The shaft was pressed through the bearings
2. Rotation was checked by hand for smoothness
3. Any binding here was corrected before continuing

This step sets the motor’s concentricity.

Mounting the Rotor

1. The rotor (with magnets and back iron installed) was mounted onto the shaft
2. Fasteners were tightened evenly
3. Rotor position was checked to maintain a consistent air gap

Spin the shaft by hand:

1. Cogging is normal
2. Scraping or contact is not

Bringing Rotor and Stator Together

1. The rotor is strongly attracted to the stator
2. Bring the parts together slowly and evenly
3. Keep fingers clear

After assembly:

1. Verify the air gap around the full rotation
2. Ensure nothing rubs at any angle

Spinning the Motor by Hand

With nothing connected to a controller:

1. Spin the shaft by hand
2. The motor now acts as a generator
3. Each phase should produce a voltage as the magnets pass the coils

If nothing is generated, something is wrong electrically.

Checking with an Oscilloscope

Connect an oscilloscope across:

1. Any two motor phases, or
2. One phase and a common reference (The place where all three phases are connected on the wye configuration)

As you spin the motor by hand, you should see:

1. A smooth, repeating waveform
2. Roughly sinusoidal shape (especially with distributed windings)

This is the motor’s back EMF, and it’s a direct result of the changing magnetic field.

What You’re Looking For

1. All phases produce similar waveforms
2. No phase is completely dead
3. No obvious distortion or flat lines

Why This Matters

If the motor can generate voltage cleanly:

1. The coils are connected properly
2. The magnetic circuit is working
3. The motor is very likely to spin under power

This quick test can save a lot of debugging later.

Connecting the Controller

1. Connect the three motor phases to a brushless motor controller
2. Phase order doesn’t matter — if it spins backward, swap any two wires
3. Start with low voltage and current limits

For this build, I used a VESC, which supports Field-Oriented Control (FOC), a control system which helps get the most performance out of the motor.

1. Connect the VESC to a battery and to your computer.
2. You can use your computer to tune various parameters of the motor.
3. Click on the sections of the detect and calculate parameters and the motor should start tuning itself.
4. After the motor is fully tuned, give the VESC a PWM input from a servo tester and the motor should spin.

Once the motor spins reliably, the next question is simple:

How well does it actually perform?

Testing doesn’t need to be perfect - even rough data teaches a lot.

What We Want to Measure

At a minimum, motor performance comes down to:

1. Speed (RPM)
2. Torque (how hard it’s turning)
3. Power (torque × speed)
4. Efficiency (mechanical power out vs electrical power in)

Measuring Electrical Power

Electrical input power is easy to measure:

1. Voltage x current from the power supply or controller
2. Most modern controllers (like a VESC) report this directly

This tells you how much energy you’re putting into the motor.

Measuring Mechanical Output

For this build, I tested the motor using a dynamometer, which directly measures torque and speed under load.

The goal is simply to apply a controllable load and see how the motor responds.

What the Data Should Look Like

Even imperfect motors usually follow the same trends:

1. Torque decreases as speed increases
2. Power peaks somewhere in the middle
3. Efficiency is lowest at very low and very high speeds

If your data roughly follows these shapes, your motor is behaving like a motor.

Don’t Expect Perfect Results

Hand-built motors:

1. Have larger air gaps
2. Lose more heat
3. Have higher friction

That’s normal. The value here is understanding why performance looks the way it does.

In my case I was able to push the motor to a peak electrical power of about 900 watts, and a peak mechanical power of about 200 watts. In the best case scenario, it was 40% efficient. Overall not great, but not the worst for a hand-built electrical motor.

No first-pass motor is perfect - and this one definitely wasn’t. The most valuable part of this project was seeing where theory met reality.

1. Efficiency Was Much Lower Than Expected

The motor worked, but it was far less efficient than I hoped.

Main reasons:

1. Thick laminations -> higher eddy current losses
2. Larger air gap than designed
3. Significant bearing and friction losses
4. Poor low-speed control without an encoder

None of these are surprising for a hand-built motor - but seeing them show up in real data was eye-opening.

2. Bearings and Axial Loads Are a Big Deal

Axial flux motors generate strong axial magnetic forces.

In my design:

1. Bearing preload wasn’t well controlled
2. Bearings relied too much on press fits
3. The magnetic field itself was effectively setting preload

For a version two, I would:

1. Use thrust or angular-contact bearings
2. Add controlled, adjustable preload
3. Design the bearing stack intentionally

3. Heat Builds Up Fast

At higher speeds and power:

1. Losses quickly turned into heat
2. Epoxy and magnets suffered
3. A magnet eventually detached at high RPM

Better thermal paths, thinner laminations, and improved efficiency would all help.

4. Magnet Retention Needs Respect

Even small magnets experience huge centrifugal forces at high RPM.

Next time I would:

1. Use more epoxy and better surface prep
2. Mechanically capture the magnets
3. Lower peak RPM or improve cooling

Magnets flying off is not theoretical - it happens fast, and it happened to me a few times.

5. Control Matters More Than I Expected

Without an encoder:

1. Low-speed torque was poor
2. Startup was unreliable
3. Testing at low RPM was difficult

For version two, an encoder would be a game-changer.

While the motor in this Instructable uses machined aluminum and laminated steel, the same ideas can be applied to a fully 3D-printable version - and that’s the version most people should start with.

The goal of this project isn’t just to build one motor, but to help people understand how motors work by building one themselves.

What Changes in the 3D-Printable Version

In the 3D-printed motor:

1. The stator is plastic, not steel
2. Coils are air-cored (no laminations)
3. The rotor is printed and holds the magnets
4. The shaft can be a bolt or precision rod

Because there’s no steel:

1. Eddy currents aren’t a concern
2. Laminations aren’t needed
3. Manufacturing becomes dramatically simpler

The tradeoff is lower torque and efficiency - which is completely fine for learning.

Why This Version Is So Valuable

The 3D-printable motor still lets you:

1. Wind real coils
2. Arrange real magnets
3. Generate real back-EMF
4. See real waveforms on an oscilloscope
5. Spin a real motor you built yourself

And it does all of that:

1. Without CNC machines
2. Without laser cutters
3. Without dangerous magnetic forces

That makes it perfect for:

1. Students
2. Makerspaces
3. First-time motor builders
4. Anyone curious how motors actually work

What You’ll Still Learn by Building It

Even with a plastic stator, you’ll gain intuition for:

1. Pole and slot count
2. Coil placement and phase wiring
3. How magnetic fields create torque
4. Why air gap matters
5. Why control and timing matter

You can even:

1. Test it as a generator
2. Drive it with a hobby ESC or VESC
3. Compare it directly to the metal version

Think of It as a Motor “Sandbox”

The 3D-printed motor is intentionally forgiving.

You can:

1. Change magnet layouts
2. Try different coil turns
3. Experiment with slot counts
4. Modify the geometry and reprint

Because the 3D-printed axial flux motor is low power, it’s easy to test using simple tools.

For this version, I included images showing how to measure speed and torque with an optical tachometer and a Prony brake.

Measuring Speed

1. Place reflective tape on the rotor or shaft
2. Aim an optical tachometer at the spinning motor
3. Each reflection corresponds to one revolution

This gives a direct RPM measurement without contacting the motor.

Measuring Torque with a Prony Brake

How It Works

1. A Kevlar string is wrapped partway around the motor shaft or a small pulley
2. Each end of the string is attached to a force sensor
3. The string applies friction to the spinning shaft

As the motor spins:

1. One side of the string is pulled tighter
2. The other side is pulled less

This creates a difference in tension between the two force sensors.

Where Torque Comes From

The torque produced by the motor is proportional to the difference in force between the two sides of the string:

Torque = (F₁ − F₂) x Radius

Where:

1. F₁ and F₂ are the readings from the two force sensors
2. Radius is the shaft or pulley radius

Using two sensors automatically cancels out:

1. String pretension
2. Small alignment errors

Final Thoughts

Axial flux motors aren’t magic.

They’re just magnetic fields, geometry, and careful engineering.

By building both a high-performance version and a fully printable version, this project shows that:

1. Motors aren’t black boxes
2. You don’t need a factory to understand them
3. Making things spin is one of the best ways to learn engineering

If this Instructable inspires you to build any motor - even a small printed one - then it’s done its job.