Coming to a CNC mill from a laser cutter, it is easy to get tripped up by the physical size of the bit when making designs. Any time you want to cut out an inside angle, you need to keep in mind that you can't reach all the way into an inside angle with a rounded bit. This comes up frequently when making furniture or any type of joinery; this post was inspired by the awesome examples of CNC joinery from this Make magazine post. Let's dive into the problem with inside corners and illustrate strategies to fix it.
The problem obviously depends on the size of your bit (let's call the bit radius R). An easy way to reduce the impact of this problem without modifying your design is to simply use a smaller bit. A laser cutter suffers from this only slightly because the 'bit size' is a tiny beam of light! Fixing the inside corner problem
You can modify your design to compensate for this problem. There are actually several ways to cover the red area shown above.
If you have…
Choosing the right 3D carving bit for the job at hand can be an extremely important factor in whether a project comes out amazingly, alright, or not at all. Combine that with having more choices of bits than materials, and choosing the right bit can be quite a difficult task. However, by answering a simple set of questions, you can greatly simplify your choice of bit. Here are the things you need to ask: What material am I cutting? What is my machine capable of? What shape am I cutting?
Let’s quickly go through each of these and what they mean. What material am I cutting?
Your material is one of the most important single factors in choosing a bit. Materials have a lot of properties that matter both for your design and cutting (hardness, density, size) as well as just for cutting (how does it chip? melting point, thermal conductivity). For any combination of these properties, one thing remains constant: your bit must be sharp. A dull bit will always cut poorly, and can actually be dangero…
One of the best upgrades for the Shapeoko is to use a spindle instead of the rotary tool that many start with. The 300 Watt Quiet Cut Spindle from Inventables works great with the Shapeoko desktop CNC. It is a great upgrade for many other DIY CNC router designs as well.
To make your life a little easier, we've compiled all the parts necessary for this upgrade into a single project that can be purchased here.
The Quiet Cut Spindle has several features that make it perfect for this application. very quiet, compared to the rotary tool, you barely hear it runninggreat tool holding, with a industry standard ER11-A collet includedadditional collets availableair cooledcompact and light weightaffordable
Hooking it up to work with the gShield (previously known as grblShield) on the Shapeoko is a pretty simple procedure that only requires a few more items, and most people should be able to perform the upgrade in a few hours. When the gShield is hooked up correctly the spindle will turn on a…