CNC Routers: Upgrade To A Spindle – Everything You Need To Know

So You Want To Upgrade Your CNC Router From A Trim Router To A Spindle...

If you have a CNC router with a trim router (like the Makita), you are likely tired of the almost unbearable noise it makes, and may be considering upgrading to a spindle because you justr can't stand it any more. But you’re uncertain about how to go about it. Or maybe you just don’t know enough about spindles to make the right choice.

We’re going to fix that for you in this article! I will explain everything you need to know to be fully equipped to decide whether a spindle upgrade is right for you.


I’m Garrett Fromme, a CNC expert and CEO of IDC Woodcraft. IDC Woodcraft is the most recognized CNC router bit company serving CNC creators with high-quality carving bits. I hope this articles serves you well. Please take a moment to review our line of CNC router bits for your carving needs.


As you read, we want to be clear on terminology and focus. When I use the words “CNC router”, I am referring to the entire CNC machine. When I use the word “router” by itself, I am referring to the trim router that is mounted on your CNC machine. 


This article is mainly written for CNC creators who own benchtop machines.

Longmill MK2 benchtop CNC router converted from Makita trim router to a spindle.


Consider getting a spindle instead!

Why Routers Are Used

Benchtop CNC routers, including brands like Longmill, Onefinity, Millright, Shapeoko, X-Carve, FoxAlien, OpenBuilds and others, typically come with trim routers instead of spindles. Trim routers are good little machines for carving. They are inexpensive and easily adapt to CNC routers. That is why many machines come with them. But as many find out, they do have significant drawbacks.


Interesetingly, the companies that make trim routers do not recommend them for use on CNC routers for a number of reasons, which we will dive into.

What To Consider Before Upgrading To A Spindle

Before we begin, there are several things you'll want o consider before choosing to do a spindle upgrade. They are:

  • How often will you run your CNC router to make CNC projects? - If you make projects fairly often, a spindle upgrade may be a good choice.
  • How long the machine will be carving during a project? - If most of your projects routinely carve for more than an hour, an upgrade is worth considering.
  • Do you plan on CNC routing as a hobby only, or will you do this as a business? - If you are going to do hobby work only, a spindle may not be right for you. On the other hand, of you are running, or going to run a CNC business, a spindle upgrade is an ideal move.
  • Will load noise for long periods of time be an issue? - If constant loud noises will be an issue, a spindle upgrade would be a good consideration.

Differences Between Routers And Spindles

Router Charactristics

  • Compact Design - They are portable, making them suitable for various light woodworking tasks.
  • Manual Operation - Requires hands-on control.
  • Speed (rpm) – Depending on th emake, some routers can achieve up to 30,000 rpms.
  • Brush Motor - Uses internal brushes to transfer electricity into rotary motion. Brushes wear out with use. They are inexpensive and easy to replace, but you will always find out they need replacing at the wrong time…when you are carving a project.
  • Lower power - Trim routers are not very powerful and can easily bog down during a carve.

Spindle Characteristics

  • Integrated Control - Designed to be controlled by the CNC control system. They have no manual controls you haveto manage manually.
  • Variable Frequency Drive (VFD) - A spindle is always controlled by a unit called a VFD, or variable frequency drive. This allows for speed adjustments based on the CNC’s g-code instructions. A VFD may have some manual interface but this will always be limited. Sensorless Vector Control built into the  VFD ensures the spindle is stays within a given RPM range despite the changing forces applied to it during a carve.
  • A VFD’s primary purpose is to convert single phase power to 3 phase power that the spindle motor requires
  • More power - Spindles are designed for increased workloads because they are built for CNC operations.
  • Less prone to breakdowns - They are built for long runtimes.
  • RPM’s - Depending on the unit and spindle controller, some spindles can achieve up to 60,000 rpms.
  • Motor Type - Comes in two variations - brushless motors (using DC) and the more common induction motor (using AC).

Consider a spindle upgrade kit for your benchtop CNC router

See Upgrade Kits Here

Power & Precision

Routers are designed to be manually operated tools. The user has a ‘feel’ for how it is performing during cuts. Because of this, the input power (torque) needed to do its work does not need to be very high. And considering that trim routers are compact, the windings of the motor that create the lower torque are simply limited (the number of windings determines the amount of powere the machine will have).


So, with lower torque, a router will generally pack less punch. This means the router is more prone to stalling during a carve because it is not strong enough to overcome the workload during cutting. This can break your router bit.


Even worse…a CNC router bit that is no longer spinning is no longer cutting, so it cannot move forward. That means the CNC machine stops moving. But the CNC control will not know this since there are no feedback loops. Basically, the control is thinking the machine has moved past the point where it stopped.


Bottom line…you will lose the zero reference points where everything is set on your CNC project. In cases when complex carves are being done, it becomes very difficult to recover to the exact original zero points.

In contrast, a spindle is a different motor type so it offers higher power and torque, which reduces the chance of stalling. In addition, the spindle control has a feedback loop that lets it know the spindle is stalling and is able to compensate to maintain rpm and torque.

Voltage requirements For Spindles and Routers

Almost all handheld routers will require 110 volts to run (USA) and will plug directly into a wall outlet. Spindles, which are also independently powered, are also usually plugged into an outlet just like a router. Although, in many cases, they can be hardwired to a power source.


The difference is, spindles can be purchased with either 110v or 220v (single phase) power requirements. The difference in voltage will determine the power supplied to the spindle from the VFD. 220v will deliver more power to the motor.


All homes with 110v service can have a 220v setup inexpensively.


Spindles are rated by wattage and can be purchased with different levels of power capability. This will be denoted by kilowatts (kw). For example, a spindle will be listed as a 0.8kw, 1.5kw, 2.2kw, etc. The higher the KW value, the more power that can be applied.

The Longmill MK2 converted to a plug and play spindle

See Upgrade Kits Here

Routers have manual speed adjustment knobs which can sometimes create up to 30,000 RPM’s (the RPM range is entirely dependent on the brand and what maximum RPM’s they have designed the router to achieve). When the knob is adjusted, the voltage to the motor is being changed. When the knob is dialed down, it is reducing the voltage applied to the motor. This translates to lower torque at lower speeds, increasing the likelihood of a stall during a carve.


Spindle speed is controlled by a separate control unit and some units are capable of a whopping 60,000 RPM! Spindle speed can be controlled manually via the VFD’s keypad or automatically via the CNC controller combined with g-code commands (g-code is the set of instructions that tell the CNC what to do).


A router will ramp up to the set speed swiftly (less than a second) when you turn it on. Whereas a spindle will ‘wind up’ to a preset speed set by the VFD. 


The speed ramp-up on a spindle is not an issue, as it still happens quickly...within 5 seconds (but it does give the feel of a jet engine firing up!). However, a dwell, or delay, may need to be set in the g-code cut file to account for the increased ramp-up time. However, this should be a non-issue if the post-processor is configured right.

A post-processor is a small computer program that writes the g-code that tells the CNC router how and when to move. To learn more about what a post-processor is, watch this video.

Noise Levels - Spindles vs Routers

Noise is, by far, the biggest factor that drives most creators to consider a spindle upgrade. Getting straight to the point, routers are load! Spindles not so much. Why?


Router and spindle noise depends on bearing precision and cooling methods. Let’s discuss bearings first. 

When it comes to bearings, there is a distinct difference in how much noise is generated depending on the precision of the bearings being used. Routers and spindles feel tight and precise, but spindles are built with much higher precision bearings which greatly reduces “rattling” in the ball bearings. 


“Rattle” is not the best term to use but is easier to visualize. When it comes to bearings precision vs noise, spin a router and spindle up to 20,000 rpm’s and the sound difference becomes abundantly clear. Less precise bearings have more play between the ball bearings and the ‘raceway’ they travel in. This translates to rattling within the bearing.


Now, add in the air cooling and you have a lot of noise! You might not think cooling and noise are related, but they are. Let me explain.


Both spindles and routers generate heat. This heat must be controlled to prevent overheating. There are two methods of cooling when it comes to routers and spindles. Air-cooled and water-cooled. 


Routers are always cooled by a fan built right onto the spinning part (spindles will have the same thing if they are air cooled). A fan blade whirring around that fast simply makes a lot of noise. Think of the sound a helicopter makes and you will get it.


Routers make a lot of noise because of air cooling fans and lower-precision bearings. Short bursts of noise is tolerable, but when the machine runs for a couple hours, it can be overwhelming. The biggest drawback is that the sound can be loud enough to penetrate walls, sending high-pitched sound throughout your home. It can even be loud enough to irritate neighbors. Routers are so loud, they require hearing protection. Of course, you should wear hearing protection regardless since the carving process from the router bit can be noisy.


Air cooled spindles are a bit quieter because of the tighter bearings and air cooling is managed better through the housing. But what really tones them down is when you have a water-cooled spindle. This type makes almost no sound at all except the sound of the bit cutting the material.


When it comes to the sound, routers are the worst! Air cooled spindles are a bit better. Water-cooled spindles are almost dead silent! If noise is an issue, you absolutely want a water-cooled spindle.


As an added note, if you plan on cutting dense materials (like aluminum), water-cooled is also highly recommended. These materials require a lot more force to cut/carve and will quickly heat up air-cooled spindles (which are only as efficient at cooling based on ambient temperature of the air being moved through them).

Spindle upgrade kits are available from PwnCNC

See Spindle Upgrade Kits

Router Bit Collet Compatibility

All routers and spindles have collets. A collet is the device that clamps onto the router bit shank and prevents it from slipping during carves.


The collets in routers are brand-specific. Meaning the collet is not standardized from one router brand to the next. If you need to replace a collet (because they eventually wear out), you can get the replacement from the manufacturer or resources that carry brand-specific collets, like IDC Woodcraft.


Spindle always use industry standard collets. Typically an ER-style collet, offering more versatility in shank selection and size.


ER style collets are made to industry standards, meaning all spindle manufacturers will use ER collets, regardless of who makes the spindle. ER collets are much more precise and offer far better holding power of your CNC router bit than most router collets.

Shank Size Capability

A router typically will not accommodate a shank larger than 1/4” on a benchtop CNC router. Spindles can adapt up to 1/2” shanks and higher, especially on pro-level CNC machines like the Phantom CNC router. Though you will rarely find the need for anything larger than 1/4" requirements on a benchtop units.

Ease Of Changing Router Bits

Bit changes on routers are always manual unless it is equipped with a special quick-change adapter. Any adaptor designed for fast tool change on a manual router will not be sold by the router maker, so it would be separately purchased.


If you have a router on your CNC machine and want quick-change capability, check out the Muscle Chuck website. They have high-quality quick-change adaptors you can add to your router. Keep in mind that adding and adaptor may reduce the z-travel limits on your CNC router.

For spindles, larger CNC routers will come with automatic tool changers (ATC). These are game-changers when it comes to bit changing. But an ATC is not commonly found on benchtop CNC machines so you will still need to change your bits manually.


NOTE: An pneumatic tool changer from PwnCNC is available  directly supporting Automatic Tool Changing for CNC’s equipped with the Masso Controller, and Manual Tool Changer option (with pneumatics) for other CNC controllers achieving tool changes with the push of a button.  Click here to learn more.

Size & Weight

Routers, as explained in the beginning of this article, are lightweight and compact, which makes them ideal for benchtop CNC routers. Spindles tend to be heavier and have a longer body to accommodate for the internal electronics, and allow for a wider range of mounting positions which enables you to have more Z clearance. 


Spindles, overall, are simply built better and last longer. If you're thinking of upgrading from a router to a spindle, ensure your CNC router has the structure to handle a spindle's extra weight.

Upgrading To A Spindle

When you are tired of the noise your router makes and wish you could upgrade to a spindle, you probably have 2 concerns. They are:

  • What is the cost
  • How much technical knowledge do you need

It used to require some intense technical understanding to integrate a spindle into a CNC router. Not anymore

Thanks to a company called PwnCNC, almost any benchtop CNC router owner can get a plug-n-play setup and have a spindle up and running within minutes to a couple hours from the moment they get the kit.


PwnCNC saw that home-based benchtop owners really wanted spindles on their CNC routers but most don’t have the technical knowledge to do it. So they designed systems that literally plug right into your CNC controller and it is virtually effortless. 


That is really good news for you because you can now easily upgrade. Of course, then there is the question, “How much does it cost?” 


Routers, for all intent and purposes, are simple motors that have been adapted for CNC routing. Their construction is simple, so they are easy to manufacture and affordable (generally around $100-$300). This helps keep the overall cost of the entire CNC machine down.


But it does not solve the horrible noise problem you have with your router.


Spindles do cost more…but not what you might think!


You can get a spindle kit through Amazon for as little as $250-$500. This method is not recommended if you are not willing to take on thetechnical challenge. Because these kits do not account for the different control configurations of various benchtop CNC routers.


On a personal note, I had initially considered buying an Amazon kit to do my upgrade, even though I knew PwnCNC had a plug and play setup for my Longmill CNC router, because I wanted to save a few bucks. But considering I am not technically savvy, and past experience has taught me the cost of going this route, I knew I’d run into issues that would require endless YouTube searching.


So, I went the smart route and got my setup fo my Longmill CNC router from PwnCNC for around $850. It literally is plug and play. Within about 2 hours, my Longmill had a spindle upgrade to a 1.5kw water-cooled spindle. I was back to making projects and it was so, so quiet. THE NOISE ISSUE WAS GONE!


Due to their customer service, support, and quality of equipment, PwnCNC has passed the Supplier Standards requirements of IDC Woodcraft. Due to this, PwnCNC is now an approved partner.

See PwnCNC Spindle Upgrade Kits

Should You Upgrade To A Spindle

Here are the basic factors you want to consider when thinking about upgrading to a spindle.

Stay with a router if you:

  • Do projects here and there as a hobbyist.
  • You are on a very tight budget.
  • Not worried about the noise a router makes.
  • Willing to replace the brushes on occasion.
  • Your CNC router is not sturdy enough to hold the extra weight (such as wood-frame machines).

Upgrade to a spindle if you:

  • Are tired of the noise from your router.
  • Plan to run your CNC daily.
  • Want long life out of your machine.
  • Want to use up to 1/2" shank bits.
  • Reduce the chance of stalls in the middle of projects.
  • Want more power from the machine.
  • Willing to invest in better equipment.

In wrapping up, while routers are the darling of light-duty tasks, spindles shine in power-packed CNC operations. Tailor your choice to your unique needs. And hey, whatever your CNC aspirations, remember IDC Woodcraft has your back.


Happy CNC’ing!