Custom Aluminum and Brass Rings




About: Bantam Tools Desktop Milling Machines provide professional reliability and precision at an affordable price. (Bantam Tools was formerly Other Machine Co.)

Hi folks! My name is Owen Smithyman, and I'm a content developer at Other Machine Co. I just got married three weeks ago, 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



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 boththe 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 "", 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 Permacel tape, cover the back of your metal stock with tape, remove the tape backing, and firmly press your stock to 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 in Otherplan

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 Setup Material.
  • Click the Material dropdown and choose Anodized Aluminum.
  • Click the Size dropdown and choose Custom.
  • Enter the dimensions of your material.
  • Click Continue.
  • If you're using the bracket, click the Align to Bracket button. If you're not, align the bottom left corner of your material with the bottom left corner of the spoilboard, which will be 0 for x, y, and z.
  • Click Done.

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 Import Files button.
  • Locate the file you saved from Fusion 360.
  • Click Import.
  • 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 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!



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    33 Discussions


    3 years ago

    But those are the most brittle metals wouldn't they warp

    1 reply

    Nope, aluminum and brass are actually pretty stable. Otherwise airplanes, MacBooks, doorknobs, and pipe fittings would all be warping.


    3 years ago

    I don't have any fancy machines, but I do have a set of hand tools, and a dremel. This is one of the aluminium rings I made.
    It has an agate stone that I cut and shaped.

    3 replies

    3 years ago on Introduction

    Ignore all of the armchair safety inspectors. They tend to be the type that believe table saws should come with training wheels and love to tell you about it in great detail. Fantastic work, indeed. I've been looking for someone that's equipped to work titanium carbide to make custom rings for my wife and I since I don't really care for traditional metals like gold and silver. I do love the look of your aluminum ring tho.


    3 years ago

    good idea, but remember that brass probably has nikkel in it.
    not sure about aluminium has it as well.

    12 replies

    Brass generally doesn't have nickle in it, unless it's "Nickel Brass." Brass does have lead in it, unless otherwise indicated. Aluminum is chock full of aluminum, unless it's "Aluminum Nickel Bronze."

    @tnetcenter: Unfortunately, lead concentrations are reported by weight overall. That doesn't reflect what's on the surface, where concentrations can to be higher. The EPA lists current acceptable levels at 8% by weight. However, per the EPA, "Brass fittings and plumbing fixtures, containing 8.0 percent or less lead, have been found to contribute high lead levels for a considerable period of time after their installation, even in cases where these devices are in contact with relatively non-corrosive waters." Most of the brass used by DIY folks is the plumbing variety, found in hardware stores. A recent study found plumbing fixtures containing about 6.5% lead by weight overall had a surface concentration of 18%.


    This is *not* a rip on this instructable, which I like very much, but rather a response to tnetcenter, above.

    If it doesn't have lead in it, it won't have lead on the surface.

    Only 1 in 5 brass alloys have lead in them. Most of the common brass alloys DON'T have lead.

    I make jewelry using brass and copper as well as the precious metals. There are very few warnings around regarding lead content in brass, probably because the most commons types of brass used for jewelry making don't have lead in them. The only brass used for jewelry making that I am aware of with lead in it is Red Brass (contains 5% lead). I haven't used that at all, if I need that particular color, I'll use copper instead.

    Actually, one reason why one might see no warnings is because the lead content is 1.5% or lower by weight - this is true of the type of brass used to make keys. For plumbing, per the California Department of Toxic Substances control, "Before January 1, 2010, the maximum allowable lead content in “lead free” pipes, pipe or
    plumbing fittings, fixtures, solder, or flux was as follows:
    0.2 percent lead in solder and flux;
    8 percent lead in pipes and pipe fittings; and
    4 percent lead by dry weight in plumbing fittings and fixtures." So, "no warnings" doesn't equate to "no lead." If you can verify the specific name of the formulation, and the manufacturer, you can probably determine the amount of lead, if any. It's sort of like the 0% trans-fats thing: Manufacturers are allowed to round down to zero if the levels are low enough. I have no idea what levels are permissible for jewelers' brass. One site lists it this way:

    "This product could contain trace amounts of lead, a chemical known to the State of California to cause cancer, birth defects or other reproductive harm. This product should not be used in jewelry or other items intended for children under the age of 12." The term "trace" is not defined.

    Jewelers Brass by definition doesn't contain any lead. Neither do the other 80% of lead-free brass alloys. Like I said, only 5 brass alloys( out of 25 to 30 alloys) contain ANY lead.'s-Brass-6...

    Olinbrass defines C226 as brass that has up to .05% lead by weight.

    Heyco Metals states their brasses contain up to .1% by weight

    Finally,, in their page on the analysis of brass microstructure (note this is not the "leaded brass" microstructure page) states:

    "Brasses frequently contain lead in order to improve machinability. The microstructure of the leaded brasses is similar to that of the unleaded brasses with the addition of almost pure lead particles found in the grain boundaries and inter-dendritic spacings. The lead is observed in the microstructure as discrete, globular particles because it is practically insoluble in solid copper. The number and size of the lead particles increases with increasing lead content."

    ALL of the brasses they analyzed contained lead. The amounts were small, but in reference to a substance where to blood-level toxicity is reached at 5 parts per million, it's still bad. In addition, two different formulations went by the name "red brass," both of which are considered "jewelers brass" or "jewelry bronze." Brasses tend to be poorly defined. Recycling old brass (as many do) is a total crapshoot, as some of these have a lot of lead - 5 to 10% by weight.

    If you have actual *links* to data that contradict this, I'd like to see them.

    The chart I was looking at when I replied to you is located on Wikipedia:

    I found several other references online that all seemed to refer back to that wikipedia chart.

    I have never run across any jewelry resources that refer to lead content in brass. That may be because brass isn't used that much in jewelry. Jewelers tend to be much more concerned with allergies than the general public and I haven't seen any references to lead as a concern. Nickel seems to be the one metal that causes the most issues with allergies. Brass isn't even mentioned in any of the literature I've seen as being a concern.

    All of the brass that I've used to this point has been purchased in wire form from local hardware stores or in sheet form from the local hobby shop.

    Base metals (copper, brass, bronze, etc.) have been getting more popular recently for use in jewelry applications, however, as I indicated earlier, none of the jewelry resources I've used has ever mentioned lead as a concern whether in brass or by itself. I don't use any solders that contain lead and there are extensive green alternatives to almost all of the harsh chemicals used by jewelers. I don't think it's as big a problem as you are trying to suggest - .05% to .1% lead content is just not very much lead at all especially considering the minute quantities that may be present in jewelry. On top of that, a significant portion of the brass used to make jewelry is likely getting plated with some other metal anyway which would seal the lead in.

    First, I'd like to apologize to othermachine for this very long discussion on his/her very fine instructable. I'll make one more comment, and then I'll shut up - I promise.

    @tnetcenter: Yes, the quantities of lead we're talking about are very small. However, when you're talking about a substance that's as toxic as lead is, they're not insignificant. A size 7 ring, in brass, would weigh about 4.5 grams, from my estimation. With a lead content of .05%, that means the ring contains about 2.1 mg of lead. Assuming that roughly .05% of that lead is on the surface - not an unreasonable assumption, given the proportionately large surface area of a ring - that means there is roughly .01 mg/10 mcg of lead that is immediately accessible. That's a very low estimate. Given lead's tendency to migrate to surfaces during production of brass, the actual amount could be very much higher. If the ring were swallowed, plating would be removed by stomach acid (as it was in this instance - this is in relation to plating over lead, not brass). I'm *not* saying that using brass is bad or irresponsible. It's just a risk factor of which many are unaware. We handle brass car or house keys, and then eat without washing our hands. If you get your blood tested, you'll be surprised at how high the lead levels are. I promise you. I think I need to do an instructable on this, just to get it out of my system...

    Hi! I was actually refuting what Kogalkaben said. I think people with nickel allergies would have very little problem with brass or aluminum. Maybe some green skin from the former, but that's due to copper, and is harmless.

    Totally, I just added info to the first page because some people are (rarely) allergic to metals other than nickel, and also to bring clarity to what's actually in brass and aluminum, because there's some misinformation going around. Thanks for your help!