Maybe you're planning on upgrading your existing CNC spindle or maybe you're building a new CNC router from scratch and you need a good spindle.
In this guide I have compiled a list of the best CNC spindles available in the market in 2021.
The best CNC spindle for your application will depend upon the hardness of the materials you intend to process and the speed with which you need to get it done.
If you don't have the time or patience to manually change tools, you can choose an Automatic Tool Changer (ATC) spindle but they are expensive compared to regular spindles.
The factors I considered while compiling this list are the power output, the build quality of the spindle, collet size, and the cooling system.
I have sorted them based on their power output, starting with low-power spindles and progressively moving up to a 4 kW spindle.
At the end of this article, I have talked about the factors to consider while selecting a spindle for your CNC.
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Here are the best CNC Spindles available today :
|2||Daedalus CNC Brushless Spindle Motor||0.5 kW|
|3||Huanyang Water Cooled CNC Spindle||0.8 kW|
|4||RATTMMOTOR Water-Cooled Spindle Kit||1.5 kW|
|5||MYSWEETY CNC Spindle Motor Kit||2.2 kW|
|6||Mophorn Spindle Motor ER20 Air Cooled||4 kW|
Best CNC Spindles 
If you are confused by the choices, you can learn how to choose a CNC spindle first.
Best CNC Spindles for your CNC Router (in increasing order of Power)
|Diameter, Length||1.7" (43mm), 3.54" (90mm)|
|Tool shaft diameter||0.02" - 0.276" (0.5 - 7 mm)|
Quick summary of Genmitsu GS 775M Spindle Motor
A spindle for low-power, high-speed applications is what the Genmitsu GS-775M can be.
The spindle weighs less than1 lb, with a body made of steel which provides good rigidity and is air-cooled. The diameter of this spindle is 1.7" and can be mounted using a clamp mount.
It is compatible with ER11 collet that can hold tools with 0.276" inches shaft diameter. This spindle is best suited for engraving on soft materials and aluminum.
The spindle doesn't have a collet holder, so you'll have to purchase the ER11 collet holder separately.
Genmitsu sells a compatible ER11 collet for this motor here- Genmitsu ER11 Collet Holder for GS 775M motor.
It can run at 20,000 RPM, which means the tool can cut faster, translating to faster cycle time.
I found the motor to be quieter than the other motors of similar speed and price, but there is a tiny bit of vibration.
The Genmitsu GS-775 was created as an upgrade for the 10,000 RPM motor on the Genmitsu 3018 CNC router. However, it can fit any CNC router with a 775 motor frame.
The wires need to be connected using spade connectors or soldering. Reversing the wires while connecting can cause the spindle to run in the opposite direction.
|Diameter, Length||2.16" (55mm), 7.55" (192mm)|
|Tool shaft diameter||0.02" - 0.354" (0.5 - 9 mm)|
Quick summary of Daedalus CNC Brushless Spindle Motor 500W ER16
The Daedalus CNC spindle motor is suitable for small CNCs and can carve on aluminum and soft materials. I have chosen the ER16 variant for this article.
The size of the collet determines the type of tool you can use, so consider the tools you intend to use and choose a collet accordingly.
For mounting the spindle, you will have to provide a 2.16" diameter clamp.
The ER16 collet provided can accommodate tools with shaft diameter between 0.02" - 0.354" shaft diameter tool, and the ER11 collet can hold tools with a 0.45” shaft diameter. They also have 400W and 600W models with an ER11 collet.
This spindle has a runout of 0.0004 - 0.0008 inches. Runout is the amount of deviation of the tool from the central axis of the spindle.
This spindle can spool up to 12,000 RPM at 48 V with a rated power of 500W and gives you good cutting speeds and feed rates.
It is a brushless spindle, and therefore the problems associated with brush wear are eliminated. In addition, the motor is quiet due to lack of brush.
You can also buy the spindle motor kit, which contains the spindle motor, motor driver, power supply unit, LCD speed display, 10 V-bit cutters, 11-ER16 collets, and a 2.16” clamp from Amazon.
|Diameter, Length||2.55" (65mm), 8.97" (228mm)|
|Tool shaft diameter||0.02" - 0.276" (0.5 - 7 mm)|
Quick summary of Huanyang Water Cooled CNC Spindle 800W 24000RPM
If you want long hours of operation for your projects, the Huanyang Water Cooled CNC spindle will be able to do it for you.
It weighs around 7 lbs and can be mounted on most CNC systems which can support a 2.55” diameter spindles.
The collet provided is ER 11 with a runout of 0.0004,” meaning you get good accuracy.
You can buy it on Amazon and is best suited for carving wood and engraving on metals and acrylics.
The minimum stable operating speed you can achieve is 6,000 RPM and can be spooled up to a speed of 24,000 RPM, letting you perform a wide range of operations.
When you run your spindle at high speeds for long durations, it can heat up pretty quickly.
In water-cooled spindles like this, the heat is taken away by pumping water into it. So yes, you’ll have to provide a cooling system for the spindle.
Water cooling is better than air cooling when there is dust involved. Air cooling blows down air over the spindle and can kick up dust. You won’t have such a problem with water-cooled spindles.
It follows a 4-bearing design and hence is more stable and can provide you good precision while also reducing the vibrations.
You will need to hook it up to a 110V - 400 Hz VFD (Variable Frequency Drive) to operate it, and it has a rated current of 7.2 A. It is a four-wire motor, with three wires for the 3 phases and one for earth.
The wiring is simple as it comes with an aviation plug, meaning you only have to plug in the connector and don’t have to solder or crimp any wires. In addition, aviation plugs provide good shielding from dust and liquid entering the terminal.
|Diameter||3.14" (80mm), 9.29" (236mm)|
|Tool shaft diameter||0.02" - 0.354" (0.5 - 9 mm)|
Quick summary of RATTMMotor 1.5KW ER16 spindle
A balance between quality and power is what you get with the RATTMMotor 1.5KW ER16 spindle kit.
The spindle has a diameter of 3.14" and can be mounted on to your CNC router using the clamp provided in the kit.
This spindle kit has the 1.5 KW ER16 Spindle, a 80mm clamp, and a 220V VFD.
You can ramp up the speed of this motor up to 24,000 RPM at a power of 1.5 KW using a 220 V supply. But, can only rotate in the clockwise direction. The speed can be varied using the VFD provided in the kit.
However, the lowest stable speed you can achieve using this kit is 9,000 RPM. You may use a different VFD to take the speed to lower ranges.
The spindle has a preinstalled ER16 collet and can hold tools in the range of 0.02" - 0.354" (0.5 - 9 mm) with a runout of 0.002".
It is a water-cooled spindle made out of stainless steel. The pump and pipes for cooling are included in the kit. This spindle suitable for engraving and cutting wood, aluminum stone and other soft materials.
The kit includes the spindle, a 220V 400Hz VFD drive, a 220V 80W water pump, 16 foot pipe, and can be bought from amazon.
|Tool shaft diameter||0.039" - 0.512" (1 - 13 mm)|
Quick summary of MYSWEETY CNC Spindle Motor - 2.2KW
A complete CNC spindle kit for your new CNC build that can cut soft materials is what you get with the MYSWEETY CNC spindle motor kit.
The spindle weighs 11 lbs, and the entire kit weighs around 22 lbs and contains the spindle motor, the VFD, a water pump, 16-foot water pipes, a 2.75” dust cover brush, 13 ER20 collets and 10 Drill bits.
You can also buy the spindle without the kit by contacting the seller through email.
You can mount the spindle on any frame that can accommodate a spindle diameter of 3.14”.The kit comes with ER20 collets and has a runout of 0.0002”, which is a considerably good precision.
You can vary the spindle speed between 0 and 24,000 RPM using the VFD and provides 2.2 KW of power. The VFD provided with the kit for controlling the speed of the spindle is a 220 V, 0-400 Hz unit.
The spindle is water-cooled, and the kit contains a 220 V submersible pump which makes it suitable for long hours of operation.
The spindle, VFD and the water pump together can draw currents of around 15 A, so you might have to provide proper breakers for setting this up.
The connectors used are aviation plugs and provide good waterproofing.
The well-labeled wires, along with the documentation and videos, will help you in the installation process. In addition, there are plenty of Youtube videos on setting up these spindles to get you through it.
|Length, Breadth, Height||5" (127mm), 4.5" (114mm), 13.5"(343mm)|
|Tool shaft diameter||0.039" - 0.512" (1 - 13 mm)|
Quick summary of Mophorn 4KW ER20 Air-Cooled Spindle
The Mophorn spindle motor is the only motor on this list to feature a square body. So if you have a frame that only holds square-shaped motors, the spindles from Mophorn are a good selection.
This spindle weighs around 19 lbs and is sturdy spindle is sturdy. It has a size of 4.5” x 5” x 13.5” and can be easier to mount than a cylindrical spindle.
You get an ER20 collet with this spindle that allows you to use tools with shaft diameters between 0.039” - 0.512” and has a runout of 0.004”.
Mophorn also makes 1.5KW ER11, 4KW ER25 , 7.5KW ER32 spindles all of which are available on Amazon.
You can vary the spindle speed between 1-18,000 RPM. To manipulate the speeds of the spindle, you’ll have to hook it up to a VFD.
It is rated at 220V and can produce 4KW of power, and will draw a maximum current of 10A at a frequency of 300 Hz.
The spindle is air-cooled and can be used for milling or engraving on wood, stone, and soft metals like aluminum.
These spindles are quiet and well-balanced, providing you with good stability to make use of the high speeds.
The material of construction is strong and can last for a long time.
Which Spindle to Use for Machining Steel
Typically, for machining steel you need low RPM (compared to RPM for aluminum and wood) and high power in your CNC spindle.
The capability to machine steel is also dependent on the rigidity of your machine and the tools used. For steel, it is recommended to choose a spindle with high power at low RPMs.
The forces acting on the tool, and consequently on the spindle, are more when machining hard materials such as steel.
It is advisable to choose a spindle with a steel body, rigid construction, and ceramic bearings. Ceramic bearings can hold the runout under greater force than metal ball bearings.
The power and speed of the CNC milling spindle is determined also by the type of machining operation you intend to do.
For example, drilling on steel requires more power than milling or turning steel.
Typically milling operations can have 50% more speed than drilling operations when processing steel.
In the case of turning, speed can be 100% more than drilling operations.
If you're a hobbyist looking to machine steel, then these maybe of interest to you:
Factors to consider while selecting a Spindle for your CNC router.
1. Size and weight
The size of the motor determines whether it can be properly mounted on your CNC router. It is also important to consider the shape of the spindle as there are cylindrical and square-shaped spindles available.
Check whether the frame of your CNC router is strong enough to carry the weight of the spindle. The stepper motors on the axes need to have enough torque to handle the weight of the motor.
2. Speed and Power
The spindle speed determines the range of work that you can do. For example, cutting soft materials require low speed as large chunks of material can be cut off easily.
In the case of metals, shaving off large pieces of metals is difficult, and hence the material removed in one cut is drastically reduced.
To achieve fast cutting speed, you will have to increase the spindle speed to make more cuts per minute.
The power of the spindle is another factor that limits the projects that you can undertake. A spindle with enough power can provide smooth cuts and prevent damage to the workpiece. On the other hand, a spindle without enough power can cause the spindle to stall.
3. Type of Cooling
Spindles with very high RPM tend to get heated quickly, and hence it is important to provide proper cooling to the spindle.
The most common types of cooling available for spindles are air cooling and water cooling. Water has a higher heat capacity than air, and hence it can remove more heat from the motor. It is best to use distilled water over regular water to prevent damage to the spindle.
Air-cooled spindles tend to have better torque characteristics than water-cooled spindles due to their design. But air-cooled spindles produce more noise than water-cooled spindles.
Typically, water-cooled spindles last longer and provide better accuracy than an air-cooled spindle.
A major problem in operating a water-cooled spindle is the effect of climatic conditions. As when the weather is cold, water may freeze up and prevent you from running the spindle.
Water cooling is preferred over air cooling when you have to operate the spindle for prolonged periods.
4. Speed Control
The low-powered spindle can be controlled by motor drivers with PWM (Pulse Width Modulation).
A VFD (Variable Frequency Drive) is preferred for high-powered spindles as they provide better control and stable operations.
It is necessary to choose the correct VFD for your spindle. An improper configuration can kill your spindle immediately. Check whether the voltage, current and frequency rating of the spindle matches your VFD ( if you already have a VFD).
It is also possible to control the speed of the spindle using the controller that runs your stepper motors. I talk in detail about the GRBL CNC controllers here- Best CNC GRBL Controllers for Hobbyists.
You may pay a high price for a spindle with high power and RPM, but if the high power and RPM are never used, the price you pay becomes wasted.
You’ll also be spending more on the drives for such spindles. So buy a spindle that satisfies the requirements of all the projects that you intend to undertake.
Spindle v/s Router for CNC
CNC Spindles are manufactured solely for the purpose that you bought them for, CNC machining.
Routers are consumer-grade devices suitable for intermittent use, whereas a spindle can work for hours on end.
Spindles make less noise than the router, but the sound of the tool against the workpiece still exists.
You can plug a router directly into a wall socket, and you'll be good to go, but a spindle requires a VFD or driver device to run them.
Routers are air-cooled devices, and spindles are available with air-cooled as well as water-cooled options. In addition, the range of speed in a spindle is greater than a router.
Routers tend to bog down under heavy load conditions; a spindle can take on heavier loads than a router.
The runout on the routers are significantly more than spindles, and it has a considerable effect on accuracy. Moreover, spindles run smoother than routers.
A router is easy to set up and does not require additional accessories, and is relatively simple to operate, whereas a spindle would require a VFD and water pump (for water-cooled spindles) to operate.
If your application requires good precision and long hours of use, a spindle, although expensive, would be a good choice for you. However, if your projects can have good error margins and have short runs, a router would be economical.