From a bar of stock to a finished precision component — Kaiming’s equipment list and machining capabilities, in full
Mention Kaiming, and most people think “the stainless steel magnetic clasp factory.”
Fair enough. Magnetic clasps are our flagship. We have been making them for over a decade — bracelets, necklaces, anklets, bag hardware — across the KA, KB, KC, KE, KH, KI, KM and KX series, all available as stock solutions.
But if you only see us as a clasp supplier, you may be missing something.
Over the past two years, we have received a number of enquiries that looked a little different:
- A German wholesale supplier of craft materials who wanted metal rings, lamp frame components and findings
- A maker brand in Devon, England, needing O rings and miniature bow shackles for dog leads
- A US stationery brand founder holding a drawing and asking whether we could make a 5 mm outer diameter connector with an internal mechanical interlock
- The CEO of a Korean golf training equipment company who wanted to join a carbon rod to a rigid component using a magnetic connector
These requests have one thing in common: none of them are magnetic clasps — but all of them are small, high-precision, custom stainless steel parts.
And that is exactly where our equipment earns its keep.
This article sets out our machine list, our capabilities and the logic we use to choose between them.
1. The equipment first: 50+ CNC machines, including 6 Japanese Star Swiss-type lathes
A Japanese-built Star Swiss-type lathe at Kaiming, model SB-20R type G. The machine is fitted with a corrugated chip extraction hose and automatic collection unit, with the control panel and display on the left of the body. Machines of this type are the workhorse for long, slender precision parts.
Kaiming currently runs 50+ CNC machines, including 6 Japanese-built Star Swiss-type lathes:
| Machine type | Quantity | Role |
|---|---|---|
| Japanese-built Star Swiss-type lathe | 6 | High precision, slender parts, continuous high-volume production |
| Domestic CNC lathes and machining centres | The remaining 40+ | General machining, prototyping, small and medium batches, cost-sensitive parts |
| Total | 50+ | — |
These two groups are not substitutes for each other — they divide the work. Many orders move between them: a domestic CNC machine produces the prototype, and once the design is frozen, production transfers to a Star Swiss-type lathe.
Panoramic view of the Kaiming workshop. On the green epoxy floor, CNC machines and automatic bar feeding units line both sides of the aisle, with the metal bar stock area on the left. Across 1,000㎡, more than 50 CNC machines run continuously.
2. Eight capabilities, broken down one by one
1. Shaft-type parts
Long, slender cylindrical parts are where a Swiss-type lathe is strongest.
What we make: micro shafts, pins, needles, connecting rods, terminal cores, the sliding locking core inside a magnetic clasp.
A real example: stainless steel pins at the 1 mm scale — as fine as a sewing needle — held to ±0.01 mm. On a conventional lathe, holding and deflection are serious problems on a part like this. A Swiss-type lathe supports the material with a guide bushing: the stock rotates and feeds while the tool cuts close to the support point, so slender parts stay stable.
2. Disc and sleeve parts
Disc-shaped or sleeve-shaped parts with steps, bores and faces.
What we make: magnetic clasp shells, connector sleeves, collars, washers, end caps, the hollow sleeve-type parts used in mouthpiece sets.
Why it matters: outside diameter, bore, face and steps can all be completed in a single setup, so concentricity is better guaranteed than across multiple operations — which is critical for clasps that have to assemble.
3. Threading (we call it thread turning)
Internal and external threads cut directly on the lathe, with no need to fit a separate insert nut.
What we make: internal threads for screwing onto a male-threaded part, externally threaded studs, threads inside tube stock.
Why it deserves its own section: this is how we produce the aluminium tube connector mentioned earlier — the tube is hollow to begin with, so once the bore is threaded it screws directly onto a mating male thread. That removes the cost of a separate insert nut, and removes the consistency problems that insert fitting tends to introduce.
4. Contoured surfaces
Not just cylinders. Steps, tapers, arcs, spherical forms and irregular profiles can all be turned.
What we make: tapered terminals, spherical clasp heads, curved decorative parts, ergonomically shaped grip sections.
5. Drilling, reaming and boring
Drilling establishes the hole, reaming brings it to size and surface finish, boring corrects positional accuracy or machines a larger diameter.
What we make: cord holes, through-channels, mating holes, precision bores.
Why it matters for clasps: the diameter and finish of the hole that your cord or webbing passes through directly determine how the assembly feels and how fast it wears. Get this wrong and even a beautiful clasp will snag and fray the cord.
6. Live tooling (mill-turn)
This is the capability most buyers overlook. With a powered tool fitted, the cutter spins and can machine non-rotational features on the rotating workpiece.
What we make: flats (spanner positions), slots, cross-holes, off-centre holes, faces, engraving positions.
Why it matters: it means an irregular-looking shape that resembles a casting can often be produced without a mould at all. It is also one of the main variables we weigh when deciding whether a part should be machined or cast — for a full comparison of the two, see our other article: One Drawing, Two Processes: What to Do When Your Part Mixes Cast and Machined Components.
7. High-precision volume production
Our standard tolerance is ±0.01 mm, and —
Prototype and production parts are machined to the same tolerance specification. A sample that fits will still fit at 10,000 units.
This matters enormously for brand customers. At many factories the sample was hand-tuned by a master machinist and production drifts away from it. We avoid that by process, not by luck.
8. Automatic bar feeding
A bar feeder keeps feeding stock into the machine; when one bar is used up, the next follows automatically.
Three benefits:
- Long unattended runs, reducing the dimensional drift that comes from manual loading
- Better consistency — the size distribution across a batch is tighter
- Lower unit cost at volume, as the labour component falls
3. Domestic CNC vs. Japanese Star Swiss-type: what actually differs
This is the question we are asked most often. Straight to the comparison:
| Domestic CNC lathe | Japanese Star Swiss-type | |
|---|---|---|
| Working principle | Workpiece held and rotated, tool feeds | Stock feeds axially through a guide bushing, tool cuts near the support point |
| Best suited to | Larger diameter, shorter parts | Slender parts (high length-to-diameter ratio), small precision parts |
| Accuracy | Stable to ±0.01 mm | More stable in the high-precision band; suits tighter tolerance zones |
| Surface finish | Good — mirror or brushed achievable | Better; slender parts resist chatter |
| Slender part behaviour | Deflection and distortion at high length-to-diameter ratios | Guide bushing supports the full length — a clear advantage on slender parts |
| Efficiency | Small to medium batches, many part numbers | High volume, continuous production |
| Machine cost | Lower | Higher (imported) |
| Machining cost | More economical | Relatively higher |
| Changeover flexibility | High — suits prototyping and frequent revisions | Longer setup; suits stable, frozen orders |
In one line: domestic CNC wins on flexibility and economy. The Star Swiss-type wins on slender parts, precision and stability at volume.
4. So which machine should your part run on?
Here is the sequence we actually use:
- Is it slender? High length-to-diameter ratio, small diameter (fine shafts, long pins, slim terminals) → Star Swiss-type
- What volume? Stable high volume once frozen → Star Swiss-type; a few hundred pieces or many part numbers → domestic CNC
- Is the design still moving? Prototyping or iteration → domestic CNC (fast changeover, lower cost)
- How demanding are the tolerances and features? Very tight bands, mill-turn with multiple features → Star Swiss-type
- How cost-sensitive is it? Conventional geometry, volume, but tolerances not extreme → domestic CNC is the better buy
A typical path looks like this:
Drawing arrives → prototype on a domestic CNC machine (from 10 pieces, about 3 weeks) → customer validates the assembly → design frozen → production transfers to a Star Swiss-type lathe → unit cost falls, consistency improves
This is also why our MOQ can be as low as 10 pieces. The prototype stage runs on domestic CNC machines, with no mould to pay for, so costs stay under control. Once you have validated the market, we move to the Swiss-type lathes for volume. You do not have to commit to a few thousand units of inventory up front.
5. Materials and blank forms: wider than you might expect
Machines are only the means. The material determines what you can actually make.
On materials, what we regularly machine:
| Material | Characteristics and typical use |
|---|---|
| Stainless steel 304 | The most common and most frequently requested choice; balanced properties, sensible cost |
| Stainless steel 316 / 316L | Marine grade, the best corrosion resistance; for saltwater, outdoor and skin-contact use; can be passivated to further reduce nickel release |
| Titanium | Lightweight, hypoallergenic, high strength; for premium jewellery and medical-adjacent products |
| Brass | Warm colour, excellent machinability; a common choice for jewellery hardware |
| Copper | Electrical and thermal conductivity, good decorative properties |
| Iron | The option for cost-sensitive parts |
| Aluminium | Lightweight, can be anodised |
| Plastics (POM, nylon, ABS, PC, PTFE) | Electrical insulation, colour-through parts, or low-cost validation before committing to metal |
Simply put: 304 for general use, 316 / 316L for saltwater, outdoor, skin-contact or corrosion-critical applications. We have mature cutting parameters and finishing processes for both.
On blank form, besides solid bar we also work with tube stock (currently stainless steel tube and aluminium tube). Tube suits parts that are hollow, need a through-channel, or need to save weight, and it uses material more efficiently.
One thing should be said clearly, though: for clasp-type components, solid bar is still the usual choice. Clasps are small, need solid strength and full thread engagement, and cutting them from bar is the most direct route. Tube is more often used on structural parts with a genuine hollow requirement.
⚠️ One boundary to state clearly: we do not produce cast parts. Sand casting, die casting and investment casting all fall outside our scope. If your drawing mixes cast and machined parts, we will tell you directly which we can make and which need a foundry — and we will be honest about the parts we cannot make. For how to tell them apart, see: One Drawing, Two Processes.
6. What all this capability has actually produced
Machines and parameters are abstract. Real examples are clearer:
- 1 mm-scale stainless steel pins — as fine as a sewing needle, held to ±0.01 mm, made possible by the guide bushing on a Swiss-type lathe
- Aluminium tube connectors with internal threads — outside diameter turned, bore threaded, screwing directly onto a male-threaded part with no insert nut
- A four-piece mouthpiece set — within one product, part 2 is turned from 304 stainless bar; the others use bar or tube depending on whether they need to be hollow
- A titanium ear pick — titanium, small, requiring both good hand feel and surface finish
- Stainless steel shafts for robot vacuum cleaners — a long-standing customer, who supplies the material while we handle the machining
- A bearing washer for the centre shaft A of a composite disc mainboard — a product we had never made before, taken on and delivered at 300 pieces
What these have in common: small dimensions, tight tolerances, modest volumes, and nothing off-the-shelf that would do the job.
That is exactly what this combination of machines is built for.
How many kinds of non-standard parts have we actually made?
Those are only a few examples. Our custom work spans more than a dozen industries. Other representative items:
- Drone components — lightweighting and high concentricity requirements
- Electronic cigarette mouthpieces — cosmetic parts where surface finish and dimensional consistency matter
- Spectacle frame parts, gem settings and metal settings
- Stage lighting hardware, lens tube housings
- Gearbox assembly input shafts
One case stays with us: a bearing washer we produced for the centre shaft A of a composite disc mainboard. We had never made that product before, but we took it on and delivered 300 pieces — the most direct proof of what “custom non-standard capability” actually means.
📖 For the full list of custom parts, read: Specialist Magnetic Jewelry Clasp Manufacturer | CNC Machining from Bar Stock & Custom Non-Standard Parts
Three ways to work with us: your material, your drawing, or your sample
| Model | Who it suits | Notes |
|---|---|---|
| Machining to drawing | Customers with a complete drawing | The most common route; produced to your tolerances and process requirements |
| Machining to sample | Customers with a physical part but no drawing | We measure and reverse-engineer it, then confirm before machining |
| Machining your material | Customers who supply their own stock | You supply the material, we do the machining — each side uses what it is best at |
💡 Why can machining your own material be cheaper? One of our long-standing shaft customers runs a large factory and buys raw material in volume, so their material cost is clearly lower. They send the material to us and commission only the machining — the customer avoids the material markup, we focus on the machining, and both sides put their resources where they count. If you have your own material channel, this model is worth considering.
7. Send us the drawing. We will tell you how to make it.
You do not need to know which machine, which process or which blank form is right before you contact a factory. That is our job.
You only need to do one thing: send the drawing.
We will tell you:
- Whether this part belongs on a Star Swiss-type lathe or a domestic CNC machine
- Bar or tube; 304 or 316 / 316L
- What tolerance is achievable, and where it needs to open up
- How long prototyping takes, what it costs, and how unit cost falls at volume
- And which parts we cannot make
Minimum order 10 pieces. Functional samples in about three weeks.
Frequently asked questions
Q: Do you only make magnetic clasps?
No. Magnetic clasps are the flagship, but the underlying capability is CNC turning of precision stainless steel components. Rings, shackles, terminals, connectors, sleeves, micro shafts, mouthpiece components, inlay parts, shaft-type parts — if it is a precision part that is primarily rotational, we can most likely make it. See: the list of non-standard parts we have produced.
Q: Do you accept small-batch orders?
Yes. We weigh the process itself more heavily than the quantity. For a brand-new non-standard part that is complex and small in quantity, the price is usually higher — because our technicians spend significant time on setup. But if the process is straightforward and there is a prospect of ongoing work, we are happy to take a few hundred pieces at a fair price even at the start. For standard items such as stainless steel magnetic clasps, we will take 100 or 200 pieces even without stock on hand, because we produce for inventory anyway.
This does not contradict our “10-piece minimum”: 10 pieces is the floor, a few hundred is a typical starting quantity, and what really drives price is process complexity — not the quantity itself.
Q: Can you machine material we supply?
Yes. We work three ways: to drawing, to sample, or using your material. If you have your own material channel and lower purchasing costs, send the material to us and commission only the machining. One of our long-standing shaft customers works this way.
Q: How many machines do you run?
We run 50+ CNC machines, including 6 Japanese-built Star Swiss-type lathes, with the remainder domestic CNC equipment. The two divide the work: prototyping and small batches mostly run on domestic machines; high volume and slender precision parts transfer to the Star Swiss-type lathes.
Q: What is the real difference between a Japanese Star Swiss-type lathe and a conventional CNC lathe?
It comes down to how the workpiece moves. On a conventional CNC lathe the workpiece is held and rotates while the tool feeds; on a Star Swiss-type lathe the stock feeds axially through a guide bushing while the tool cuts near the support point. The latter is far kinder to slender parts — less deflection and distortion, more stable accuracy and surface finish, and better suited to high-volume continuous production.
Q: My part is very thin and long. Can you machine it?
Very likely yes. Slender parts are exactly what a Swiss-type lathe is for. We have produced 1 mm-scale stainless steel pins as fine as a sewing needle, held to ±0.01 mm. Send the drawing and we will confirm, then give you a clear answer.
Q: What materials can you machine?
Stainless steel (304, 316 / 316L), titanium, brass, copper, iron, aluminium, and plastics. On blank form, besides solid bar we also run tube stock (currently stainless steel tube and aluminium tube). Clasp-type components are usually cut from solid bar.
Q: What is your minimum order for custom machined parts?
10 pieces — and that applies to custom parts, not just stock items. Because CNC turning requires no mould, small batches are economical rather than exceptional. Prototyping takes about three weeks.
Q: Can you produce cast parts?
No. Sand casting, die casting and investment casting all fall outside our manufacturing scope. If your drawing mixes two processes, we will help you separate them rather than quote for the parts we cannot do well. See One Drawing, Two Processes.
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.
