Machining is one of those really impressive skills that we all wish we could develop. You can do so much with it. You could make replacement parts for your car, build incredible structures, or even recreate Aragorn’s sword Anduril. Anything is possible when you understand the process and the tools.
Machining has developed a reputation online for being pretty simple. We’re sorry to tell you that this craft involves a lot more than pushing a few buttons. That being said, we’ve put together this article to help improve your home machining experience.
Here are 10 tips and tricks that we learned the hard way, so you don’t have to:
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Don’t limit yourself to metal
This may seem like a pretty obvious comment, but many beginners don’t realize that they aren’t limited to metal. Wood and resin are other great options to make your machining projects out of.
4. Learn CNC
When you first get your CNC milling machine it can be really tempting to jump straight in and start making things.
That is not something we would recommend doing.
These machines can create some amazing things. In order to do that they need a lot of complex programming. By taking the time to learn CNC and to understand your machine you can save yourself a lot of hassle and wasted materials.
Machining is a reductive sculpting method. You can always take more away, but you can’t add more onto the metal. A cautious mindset will serve you well when doing at-home machining.
5. Always fully model your design before you begin
This is by far the most important tip on this list. And trust us you’ll be thanking us endlessly for this one.
3D modeling is a learning curve, and you won’t get everything right on the first go. However, you’ll be surprised by how fully mapping out your project will alert you to issues you hadn’t expected.
If you fully plan your project in advance you’ll find yourself having to start over a lot less frequently.
6. Make all your designs with error rates in mind
Another simple tip here: make sure that your roughing error rates are correct. If they are too small you probably won’t be able to put your project together at the end. There really isn’t such a thing as too big when it comes to error margins in machining.
5. Pseudo roughing and strategic cuts are your new best friends
More complex designs will benefit most from being fully modeled before beginning the project. If you do this you can make the most of time-saving techniques like pseudo roughing, strategic cuts, and even mill swapping.
It’s hard to incorporate these techniques into a build when you’re halfway through it. However, if you plan them out in advance you can save yourself a huge amount of time and effort.
6. Use dowels for small, thin parts
The thinner the part the more likely it is to break when the mill touches it. You will have to prepare for this when designing your piece. This is one of the most important reasons why you should map out everything in advance.
The easiest way to avoid breakages with thin pieces is to use dowels to attach them to the sacrificial block. However, to make this work correctly you will have to build dowel guides into your design.
These guides will help the piece to sit securely on the dowels and not fracture or move around under the pressure of the mill.
7. Collet tightening tricks
If you want to do any machining at home, you will inevitably spend a lot of time tightening collets.
Here is a simple trick to speed up that process:
If the top wrench is on the right, and the bottom wrench is pointing to the left: pulling these towards each other will tighten the collet.
If the top wrench is pointing towards the left, and the bottom wrench is on the right: pulling these towards each other will loosen the collet.
You’re very welcome.
8. Calipers (and why you should use them)
Calipers are one of the most important Machining tools. We recommend investing in a good pair. Getting an accurate idea of the thickness of the material you’re working with can make or break your project.
For this reason, a good pair of calipers is essential.
Many people find that the measurements they get from their calipers fluctuate or vary depending on which part of the metal they measure. This is not unusual, or anything to worry about. It simply means that the material has an uneven thickness. This can be fixed by using the surfacing program on your CNC.
9. Lubrication (and why you should use it)
Lubricating harder materials can make your life a lot easier, and give you a better end result. Before beginning work on a harder material (like aluminum) apply a coating of cutting fluid.
What are the benefits of using cutting fluid? Firstly, it allows for a smoother mill movement. Secondly, it prevents both the metal and the mill from overheating.
Too much cutting fluid can cause overheating. The excess fluid causes the chips to stick together too close to the mill, leaving no room for any of the heat created by the milling process to escape.
Cutting fluid can be easily removed using soapy hot water and a cotton cloth.
10. Learn the difference between surfacing and roughing
The three most common processes you will use whilst machining are roughing, surfacing, and finishing. People often mistake roughing and surfacing as being interchangeable activities. However, they are very different.
Here is a quick guide to roughing and surfacing:
Roughing – as the name suggests is the process of cutting out the rough shape of your piece. This process should include a finishing margin (extra material left on the piece that will be fine-tuned when you get to the finishing stage). This is a fairly quick process that allows you to work with a much smaller piece of metal.
Surfacing – this is the process of evening out the piece of metal you are working on. As mentioned about calipers will often give fluctuating readings, this is because the metal is thicker in some places than others. Surfacing will fix this.