Custom Aluminum and Brass Rings
Hi folks! My name is Owen Smithyman, and I’m a content developer at Other Machine Co. I recently got married, and to mark the occasion and what it represents, I now wear a gold ring on my finger. I did not make this ring on the Othermill, but it inspired me to try milling rings myself, since the Othermill is great at cutting metals like brass and aluminum. I was happy to discover that rings are a great CNC project. They’re very simple yet elegant. They can be easily customized to fit any size finger, and they offer a good example of hand finishing. They also don’t have any little nooks and crannies that require small tools, so you can use a 1/8" flat end mill the entire time, which is one of the easiest tools to use.
Sound like fun? Let’s get started!
Note: For people with metal allergies, look up the composition of your metal to make sure it doesn’t contain anything you’re allergic to. Nickel allergies are the most common, but all alloys of brass and alloys of aluminum are nickel-free except nickel brass (also called nickel silver). We like 360 brass and 6061 aluminum for milling. Brass is primarily copper and zinc, and aluminum is 95-99% aluminum. If you’re not sure, go with aluminum. Its alloys are much better documented, and it has very low copper content.
Step 1: Tools and Materials
- Computer running Otherplan
- Flat end mill, 1/8“
- Scotch-Brite pad or other medium-weight scouring pad
- Digital calipers
- High-Strength Double-Sided Tape
- Rubbing alcohol to remove the tape
- Autodesk Fusion 360 software
- Existing ring that fits your finger comfortably
Step 2: Measure and Calculate Your Ring Size
One of the major benefits of using the Othermill to manufacture things is that you can customize them! You’re not stuck with an off-the-shelf product that may or may not fit you.
To make sure the ring fits your finger, use digital calipers to measure the inside diameter of an existing ring that fits your finger comfortably. If you don’t have calipers, you can use a ruler. Don’t try to measure your finger directly because your skin will move out of the way when you squeeze it with a measuring device, giving you an inaccurate measurement. My ring’s inner diameter is 0.780".
From here, you can decide and calculate how thick and how tall you want your ring to be. In this case, I want my ring to be 0.040" thick and 0.250" tall. To get a thickness of 0.040", I need to have an outer diameter of 0.860". To calculate that, double the band thickness and add it to the inner diameter (desired thickness * 2 + inner diameter = outer diameter).
Here are my measurements:
- Inner diameter: 0.780"
- Outer diameter: 0.860"
- Height: 0.250"
We’ll use these in the next step.
Step 3: Set Up the Ring Parameters in Fusion 360
Learning Fusion 360 is a lot to ask for a simple tutorial, so I’m providing my ring model, which you can modify to fit your finger. If you’d like to learn Fusion 360 from the ground up, you can start here. Otherwise, download the Ring Fusion file.f3d file from this step. Here’s how to open it in Fusion 360:
- Click File > New Design From File
- Locate the downloaded file and click Open
Once the file opens, we’ll start by setting the inner and outer diameter of the ring:
- Switch to the Model workspace if you’re not already in it.
- Under the Modify menu, choose Change Parameters.
- To change the outer diameter, change the Diameter parameter under CylinderPrimitive1.
- To change the inner diameter, change the HoleDiameter parameter under Hole1.
- To change the height of the ring, change both the Height and HoleDepth parameters.
- Click OK when done.
Step 4: Measure Your Material and Set Up Your Stock
To make sure Otherplan knows where to cut, you need to set up your stock, which is another word for your material. For this project, you’ll be using brass or aluminum stock. If you bought it from our store, the brass will be 4"x4"x0.25" or 4"x5"x0.25", and the aluminum will be 4"x4"x0.25". If you have your own stock that has different dimensions (which I do in this example), you’ll need to measure those dimensions, ideally with digital calipers.
My stock dimensions are:
- Width (x): 3.00"
- Depth (y): 2.50"
- Height (z): 0.38"
Note: This is the most important dimension because if you set it too small, the tool will cut deeper than expected, which can break it, dull it, or damage your machine. If you’re not sure, err on the side of too large. You may mill some air for a bit, but it’s better than the alternative.
Once you know the dimensions of your stock, enter them into the parameters of the setup. The setup is a collection of settings that describe what will be milled and how:
- Double-click (or right-click and choose Edit) on Setup1 in the Browser panel.
- In the dialog box that opens, click the Stock tab.
- Enter your stock dimensions in the Width (x), Depth (y), and Height (z) boxes.
- Click OK.
Step 5: Generate Toolpaths
Now we’re going to generate the toolpaths that the Othermill will follow as it mills your project. I’ve already created Facing and Ramp toolpaths, but they need to be calculated again for the new stock dimensions you just entered:
- Right-click on Face1 in the browser panel and choose Generate Toolpath.
- Right-click on Ramp1 in the browser panel and choose Generate Toolpath.
Fusion will recalculate the toolpaths and display them around your model. If your ring model is the exact same height as your stock, you’ll get a little yellow warning icon next to the Face1 toolpath, but you can ignore it because you won’t be needing that toolpath.
If you’re curious about the settings, you can double-click (or right-click and choose Edit) either of the toolpaths to see all the parameters. We’re using a 1/8" flat end mill for both toolpaths. The settings are optimized for aluminum, but they’ll also work great with brass.
Step 6: Post-Process Your Toolpaths
Now that we’ve generated the toolpaths in Fusion, we need to output them in a form that we can import into Otherplan. To do this, we’ll use the Othermill post-processor that’s built into Fusion. But first you need to determine whether you need both the Facing and Ramp toolpath or just the Ramp toolpath. If your ring is the same height as your stock (i.e. the surface of the ring is even with the surface of the stock), you only need the Ramp toolpath, since the Facing toolpath is there to remove any material thicker than the ring. Here’s how to post-process your toolpaths:
- In the Browser panel, locate the two toolpaths.
- If your stock is thicker than your ring, hold down the Shift key and select both the Facing and Ramp toolpaths. If your stock and ring are the same height, just select the Ramp toolpath.
- Under the Actions menu, choose Post Process.
- In the dialog box that opens, click the Post Processor dropdown menu and select “othermill.cps - Generic Othermill (Otherplan)”.
- Uncheck the box next to Open NC file in editor.
- Click OK and navigate to the directory where you’d like to save your file.
- Type a name for your file including the .nc file extension — “awesomering.nc”, for example.
- If you didn’t include the .nc file extension, go add it now (otherwise Otherplan won’t recognize your file).
Step 7: Attach Your Material to the Bed
Now we’ll attach the stock to the bed. I like to use the alignment bracket as a fixturing aid because it braces the material on two sides, so you’ll see it attached in the project photos. If you’re not using it, just line up your material with the bottom left corner of the spoilboard.
If you have Nitto tape, cover the back of your metal stock with tape, remove the tape backing, and firmly press your stock onto the bed.
If you don’t have tape, hot glue around the edges of your stock, where it meets the bed (don’t glue under it). Using the bracket makes it so you only have to hot glue the edges that aren’t touching the bracket. Let your material sit there for a minute or two, then wiggle it back and forth. It should feel firmly anchored to the bed.
Step 8: Set Up Your Material
Remember how we set the dimensions of your stock in Fusion 360? Now we’re going to do the same thing in Otherplan. This way they’ll match. Turn on the Othermill, open Otherplan, and do the following:
- Click the Material dropdown and choose Generic.
- Under Size, enter your material dimensions.
Step 9: Set Your Tool
Now we’re going to switch to a 1/8" flat end mill, which is the tool that was selected in Fusion 360 when we created the toolpaths. Feel free to skip this step if you already have one loaded.
- Click the Change button in the upper right panel.
- Follow the prompts to remove the current tool and insert and locate the 1/8" flat end mill.
Step 10: Import Your File and Start Milling
It’s finally time to import your .nc file and start milling!
- Click the Open Files button.
- Locate the file you saved from Fusion 360.
- Click Open.
- Choose a 1/8" flat end mill in the panel for the file you just imported.
- Click Start Cutting.
- Hover your finger over the ESC key on your keyboard in case anything goes wrong as the tool touches down to the material.
Step 11: Hand-Finish the Ring
Once your ring is done being milled, you’ll need to clean off the swarf and then hand-finish it with a Scotch-Brite pad.
For the top and bottom of the ring, I like to lay the Scotch-Brite on a flat surface and then rub the ring in a circle.
For the outside, I like to rub it back and forth lengthwise. For the inside, I used a small piece of Scotch-Brite and then a Dremel with a polishing wheel because I was impatient. It’s up to you — naturally, the inside won’t be visible when you’re wearing it.
Congrats! You just made your own jewelry with the Othermill. Wear it proudly and know that you’re part of a revolution to make high-quality manufacturing available to everyone.
If you have any questions, don’t hesitate to contact us at firstname.lastname@example.org. We’re here to help! And if you do make a ring, be sure to share it with us. We’d love to see it!