A buyer’s guide to the three metals we machine most — allergy, weight, corrosion, cost and finish, compared honestly
A designer came to us recently with a stainless steel necklace clasp for a 2027 collection. He asked about the process, sample and production pricing, minimum order, tooling cost, lead time and shipping. The drawing was not final — he was still at the stage of working out how this all works.
In our reply we told him: we machine all three — stainless steel, brass and titanium.
Almost every time we say that, the next question follows: “So which one should I choose for this?”
It is a question worth asking — because the metal you choose affects four things that matter commercially: how it feels to wear, whether it survives your customer’s environment, what it costs, and whether it can be sold in your target market at all.
We machine all three, so we have no material to push. That makes this guide worth reading.
The short answer
| 304 stainless | 316 / 316L stainless | Brass | Titanium | |
|---|---|---|---|---|
| Nickel content | Contains nickel | Contains nickel | Usually nickel-free* | Nickel-free |
| Hypoallergenic | Generally yes, once passivated | Generally yes, once passivated | Usually yes — but see note | Yes, fully |
| Density | ~8.0 g/cm³ | ~8.0 g/cm³ | ~8.5 g/cm³ | ~4.5 g/cm³ |
| Relative weight | Baseline | Baseline | Heavier than steel | ~40% lighter than steel |
| Corrosion resistance | Good | Best (marine grade) | Moderate — tarnishes | Excellent |
| Saltwater / sweat | Adequate inland | Recommended | Not recommended | Excellent |
| Warm colour | No — cool, white-grey | No — cool, white-grey | Yes — warm gold tone | No — grey, slightly warm |
| Machinability | Good | Fair (tougher than 304) | Excellent | Difficult |
| Relative cost | Lowest | Moderate | Moderate to high | Highest |
| Best for | General-purpose, indoor | Beach, outdoor, sport, sensitive skin | Warm-toned, vintage, fashion | Lightweight, premium, medical-adjacent |
*Brass is a copper-zinc alloy and is generally nickel-free, but some grades and — more importantly — some plated finishes contain nickel. Always confirm with your supplier.
The same part, in all three metals
Numbers in a table only go so far. Here is one identical geometry — the same teardrop component, CNC-machined in one piece — produced in stainless steel, brass and titanium, side by side.
Three things worth reading off this photo:
- Stainless is cool and neutral. It sits next to silver and white gold without clashing, which is why it is the default.
- Brass is genuinely warm. That gold tone needs no plating at all — which is its main advantage, and also why it eventually tarnishes.
- Titanium can be coloured by anodising. The blue-purple here is not a coating: anodising grows a controlled oxide layer on the titanium, and the colour comes from how light interferes in that layer. Because nothing is deposited on top, there is no layer to chip or peel — a real advantage on a part that gets handled every day.
That last point matters more than it sounds. PVD is an excellent hard coating on stainless, but it is still a layer applied to the surface. Anodised titanium colour is integral to the metal.
Two things that surprise most buyers
Brass is heavier than stainless steel, not lighter
This catches people out. Brass has a density of around 8.5 g/cm³; stainless steel sits around 8.0 g/cm³.
So if weight is your concern — a large statement clasp, a chunky chain, anything worn for hours — brass will feel heavier than the same part in steel. Titanium, at roughly 4.5 g/cm³, is the only genuinely lightweight option of the three, at about 40% lighter than stainless.
“Titanium is stronger than steel” is only half true
It depends entirely on the grade.
- Commercially pure titanium (Grade 2) — the grade most often used for jewellery — has a tensile strength lower than 304 stainless steel.
- Ti-6Al-4V (Grade 5) — the alloy used in aerospace and medical implants — is considerably stronger than 304.
So if you are specifying titanium for strength, say which grade you mean. If you are specifying it for lightness or for allergies, Grade 2 will do and will cost less.
The three metals, one at a time
304 stainless steel — the default
304 is the most widely used stainless grade in the world, and the one most buyers mean when they write “stainless steel.”
Why it is the default: good corrosion resistance in normal environments, readily available, and the most economical of the three to machine. It takes a mirror polish, a brushed finish or a PVD colour coating well.
Where it struggles: prolonged exposure to chlorides — saltwater, pool water, heavy sweat. 304 can develop surface rust or pitting in those conditions. If your product is marketed as beach-safe, sport-proof or sweat-proof, 304 is not the grade to specify.
Choose 304 if: your clasp is worn indoors or in everyday conditions, weight is not critical, and you want the best balance of performance and cost.
316 / 316L stainless steel — the marine grade
The difference from 304 is molybdenum, typically 2–3%. That single addition dramatically improves resistance to chlorides.
316L — the “L” means low carbon — is preferred for parts that will be welded and, in our experience, for skin-contact products, because the lower carbon content reduces the risk of sensitisation and intergranular corrosion.
Why it matters commercially: 316L is the grade that lets you honestly describe a product as marine grade, saltwater-safe or sweat-resistant. For a brand selling beach jewellery, coastal lifestyle, or anything worn during sport, this is not a technical detail — it is a marketing claim you can defend.
We also passivate 316L. Passivation removes free iron from the surface and promotes a stable chromium oxide layer. It improves corrosion resistance and reduces nickel release — which matters if you sell into the EU.
Choose 316L if: your product sees saltwater, sweat or outdoor use; if you sell in the EU and need nickel release documentation; or if you simply want the most corrosion-resistant steel option.
Brass — the warm one
Brass is a copper-zinc alloy, and it is the only one of the three with a genuinely warm, gold-like colour straight out of the machine.
Why designers pick it: the colour. No plating required to get that tone, which is a real advantage — a plated finish can scratch or wear, while solid brass stays brass.
Two honest caveats:
- Brass tarnishes. Copper oxidises, and brass will darken over time. Some brands want this — it reads as vintage or living finish. Others do not, and will need a protective lacquer or PVD coating, which adds a step and a cost.
- Brass can discolour skin. Copper oxidation can leave a green mark on the wearer. This is well known to anyone who has worn a cheap brass ring, and it is worth thinking about if your clasp sits against the neck for hours.
On the plus side, brass is the easiest of the three to machine. It cuts cleanly, holds detail well, and produces excellent surface finishes with less tool wear — which partly offsets its material cost.
Choose brass if: the warm tone is central to your design, you want an unplated gold-like colour, and your customer is not wearing it in saltwater or heavy sweat.
Titanium — the premium one
Titanium is the specialist choice, and it earns its price in three specific ways.
1. It is genuinely hypoallergenic. Titanium contains no nickel. For customers with a documented nickel allergy — a meaningful share of the jewellery market — this is the only metal of the three that removes the question entirely.
2. It is light. Roughly 40% lighter than stainless steel. On a large or chunky clasp, the difference is noticeable the moment you pick it up.
3. It is corrosion-proof in practice. Titanium forms a passive oxide layer that resists saltwater, sweat and most chemicals. It is the metal used for marine hardware and medical implants for good reason.
The trade-off is cost, and it comes from two directions. Titanium stock is expensive, and titanium is difficult to machine: it conducts heat poorly, so cutting heat concentrates in the tool rather than leaving with the chip, which means slower cutting speeds, more tool wear and longer cycle times. You pay for the material and for the machining.
Choose titanium if: you are selling into the allergy-sensitive market, weight genuinely matters, or you are positioning a premium product where the material itself is part of the story.
The five questions that actually decide it
Work through these in order. Most projects resolve after the first two.
1. Where will it be worn?
| Environment | Recommended |
|---|---|
| Indoor, everyday | 304 |
| Beach, coastal, saltwater | 316L |
| Sport, heavy sweat | 316L or titanium |
| Medical-adjacent, implant-adjacent | Titanium |
| Fashion, occasional wear | Brass or 304 |
This is the first question, because it can eliminate options outright. A brass clasp in a “beach-safe” collection will come back to you.
2. Who is wearing it — and where do you sell?
If you sell into the EU, nickel release matters. REACH restricts nickel release from articles in prolonged contact with the skin, and the limits are tight — measured by EN 1811, the threshold is 0.5 µg/cm²/week for general prolonged skin contact and 0.2 µg/cm²/week for post assemblies used in pierced parts.
What this means practically:
- Titanium — no nickel, no issue.
- 316L, passivated — generally passes, but test it, and ask for the report.
- 304, passivated — often passes, but has less margin than 316L.
- Brass — confirm the exact alloy and any plating. Nickel can enter through the plating even when the base alloy is nickel-free.
We supply material certificates and can arrange nickel release testing. Ask for the report before you commit to a market claim, not after.
3. Does weight matter?
For a small clasp, usually not. For a large statement piece, yes — and then titanium is the only real answer. Remember that brass is heavier than steel, not lighter.
4. What colour do you want?
- White, cool, contemporary → 304 or 316L
- Warm gold tone, unplated → brass
- Grey with a slightly warm cast, technical → titanium
- A specific colour — black, rose, gold → any of them, via PVD coating
- Colour on titanium that will never chip → anodising, as shown in the photo above
PVD is worth knowing about: it gives a hard, durable coloured layer on stainless and titanium, and it performs far better than traditional plating on a part that gets handled daily.
On titanium there is a further option. Anodising grows a controlled oxide layer, and the colour comes from light interference within it — so unlike PVD or plating, there is no deposited layer to chip or wear off. It is a genuine advantage on a clasp that is opened and closed every day. Once again, tell us which grade and which colour you need, and we will confirm what is achievable.
5. What is your budget?
Roughly, from most to least economical: 304 → 316L → brass → titanium, though brass moves around with the copper price. Titanium is clearly the most expensive, and the gap widens on complex parts because of the machining difficulty.
Two options buyers often overlook
Mix metals within one clasp
There is no rule that a clasp must be a single material. A common and sensible combination:
- Brass outer shell for the warm colour, with a stainless insert or spring inside for strength and wear resistance
- Titanium body with a stainless mechanism where the moving parts need toughness
This lets you get the look you want without compromising the parts that actually take the load.
Prototype in one metal, produce in another
Because CNC machining needs no mould, testing a design in 304 and then producing in 316L or titanium costs you nothing in tooling. You can ask us to make your first 10 pieces in the cheaper metal to validate fit and feel, then switch the material for production.
That is a genuinely low-risk way to make this decision — you do not have to guess on paper. We wrote more about why there is no tooling cost in this article.
What we machine, and what we do not
We regularly machine 304, 316 and 316L stainless steel, titanium, brass, copper, iron, aluminium and engineering plastics. For jewellery hardware specifically, the three discussed here cover almost every enquiry we receive.
Two notes on how we work:
- Blank form: most clasps are cut from solid bar, because they need solid strength and full thread engagement. We also run tube stock — currently stainless and aluminium tube — for parts with a genuine hollow requirement.
- What we do not do: we do not cast. Sand casting, die casting and investment casting are outside our scope. If a component genuinely needs a cast geometry, we will tell you rather than quote for it. Our guide to telling the two apart is here.
Finishes available across these metals: mirror polish, brushed/satin, PVD colour coating, and passivation (the last specifically improves corrosion resistance and reduces nickel release on stainless).
Still not sure? Send us the drawing
You do not have to settle the material question before you contact us. Tell us three things and we will give you a recommendation grounded in what the part actually has to do:
- Where it will be worn — beach, sport, everyday, occasional
- Where you sell — EU, US, worldwide
- What matters most — cost, weight, colour, or allergy-safe positioning
Send us your drawing. We will tell you which metal we would choose and why, and quote the ones you want to compare.
Minimum order 10 pieces. Prototypes in about three weeks.
Frequently asked questions
Q: Which is best for a necklace clasp — stainless steel, brass or titanium?
It depends on where it is worn and who wears it. 304 stainless is the economical default for everyday wear. 316L is the one to choose for saltwater, sweat or outdoor use. Brass gives a warm unplated gold tone but tarnishes and can discolour skin. Titanium is the choice for allergy-sensitive customers and where weight matters, at the highest cost.
Q: Is brass lighter than stainless steel?
No — brass is slightly heavier, at roughly 8.5 g/cm³ against stainless steel’s 8.0 g/cm³. Titanium, at about 4.5 g/cm³, is the lightweight option, around 40% lighter than stainless.
Q: Is titanium stronger than stainless steel?
It depends on the grade. Commercially pure titanium (Grade 2), the common jewellery grade, is less strong than 304 stainless. Ti-6Al-4V (Grade 5) is considerably stronger. Always specify the grade when strength is the reason you are choosing titanium.
Q: Does stainless steel jewellery cause nickel allergy?
304 and 316L both contain nickel, but a stable passive layer keeps release very low, and most people with sensitivities tolerate them. Passivation reduces release further. If you need to guarantee no nickel at all, titanium is the answer.
Q: What are the nickel release limits in the EU?
Under REACH, for articles in prolonged contact with the skin, nickel release is limited to 0.5 µg/cm²/week as measured by EN 1811, and to 0.2 µg/cm²/week for post assemblies in pierced parts. Confirm against the current regulation for your product category, and test rather than assume.
Q: Can you make the same clasp in two different metals so I can compare?
Yes. Because CNC machining requires no mould, running 10 pieces in 304 and 10 in brass is a normal order, not a special request. Many customers prototype in one metal and produce in another.
Q: Can you plate or colour these metals?
We offer PVD colour coating, which gives a durable coloured layer on stainless steel and titanium and performs better than conventional plating on handled parts. We also offer mirror polish, brushed finishes, and passivation for stainless.
Q: What is your minimum order and lead time?
Ten pieces, for custom parts as well as stock items. New custom parts take about three weeks to a finished functional sample; simple parts with material in stock can ship in about seven days.
Kaiming (kmintjewelry.com) / Dongguan Kaiming Stainless Steel Jewelry Co., Ltd. — CNC machining of precision components in stainless steel, titanium and brass. 50+ CNC machines including 6 Japanese Star Swiss-type lathes, 1,000㎡ workshop, tolerances to ±0.01 mm, 10-piece minimum order.
