Choosing the spindle or router for a CNC machine

There are a few things to consider when choosing a spindle or router for a CNC machine. I’ve always thought that the word spindle doesn’t really do justice to what is operating the cutting tool. It makes it sound a bit toy-like, maybe that’s just me but in CNC terminology it refers to the thing that turns the cutting bit regardless of its size or power.

How to choose a CNC spindle

When I first started to experiment with building a CNC machine I just used my Dremel type tool. This is the actual tool I used to start with. The first problem I encountered was to mount it. You’ve got to fix it as rigidly as possible to the back board. I couldn’t find anything suitable so I had to make something. Basically I got a piece of 18mm thick wood and cut a hole in it with a hole cutting saw.

I cut a small piece out of it to make it into a clamp and drilled holes through it to clamp and fix it to the back. It held pretty well to try out the machine but to use it long term I’d probably need to upgrade this as it was possible to get it to move by pushing it with my hand. You ideally want it so solid that it won’t flex or move no matter how hard you push it.

Cheap CNC spindle

The Dremel tool is only about 130 Watts but I wanted to see if it would be able to cut and engrave plastic acrylic. The first test for engraving the acrylic was a success just using cheap engraving bits. The second test was to see if it would actually cut through acrylic.

The first bits I used didn’t work at all and the acrylic just melted on the bit. I did a bit of research and bought some different bits and to my surprise they cut pretty well although in hindsight it did take quite a while due to the slow federate and depth of cut.

I did try to increase the feed rate and depth of cut but that did result in the bits breaking. After a bit of experimenting with cutting bits and feed rates I was able to use the Dremel type tool to successfully cut, drill and engrave 3mm black acrylic plastic.

The picture above shows the spindle that was included in the pack I got with the 3018 CNC from Amazon.

Best hobby CNC router spindle

Having looked at a few videos I saw some people were cutting acrylic almost effortlessly so I decided to try a different spindle. There were a few videos of upgrades of the 3018 CNC machine. This is a machine that I own and I have an article about it here if you want more information.

The upgrade for the 3018 machine used a 500 watt spindle. This looked OK but for less money something else had caught my eye (not literally – always where eye protection) quite a few people were using the Makita hand laminator / router. This was rated at about 700 Watts with a variable speed of 10,000 to 30,000 rpm.

This was the device I went for in the end.

Here are some tips for using the device as a CNC spindle. The first worry for me was how heavy it was compared to my Dremel type tool. Would my CNC machines Y axis be strong enough to support the new Z axis that it would require and would the motors be powerful enough to drive it?

Yes was the answer to both of these question. I’m always surprised how powerful the NEMA 17 motors are.

The way I was going to mount it was to use 90 degree angles to fix a baseboard which the included router base would screw onto. The original screws in the base are M4 so I just needed to get longer ones to go through the wooden base.

This wasn’t ideal as there’s not much space between the cutting tool and the base and you can’t see what’s happening like you can with the Dremel type tool, as the base blocks what you can see when the machine is running.

The size of the base also doesn’t allow much clearance and limits how high the clamping can be. I liked using aluminium angle to clamp sheet material due to its strength over flat lengths however this would be out of the question using the router base.

What I needed was to get rid of the base and find a way to fix it like my Dremel type tool. Losing the base would mean I could see what was happening and give as much clearance as I needed. The Makita has a cylindrical body of about 65mm diameter and its shape also makes it extremely easy to fit on a CNC machine. I used these clamps that I got from Amazon.

They are solid steel and fit the router extremely firmly and you also have the option to remove it if you need to by just unbolting it. Using these solid clamps meant that there was no flex or movement no matter how much pressure you applied.

Best CNC spindle for aluminium

The extra power and stability should mean I should be able to mill aluminium when the need arises. There are plenty of people who use it regularly to mill aluminium. There doesn’t seem to be many people who have used this router have any regrets about it and at the price you can’t really complain. I also got spare brushes with mine as well as a few other accessories which should come in useful.

Then more powerful spindles seem to make the whole machine better. Just look at the YouTube videos in which spindle upgrades seem to be popular. You don’t get many people that are unhappy after a spindle upgrade.