Drill Bit Size Guide for Jewelers
Wire, Cord, Chain, and Findings Hole Size Reference for Jewelry
Proper hole sizing is essential in drilled stone jewelry. Incorrect sizing can prevent assembly, weaken the stone, or compromise the finished piece. This reference provides recommended drill bit sizes for wire, cord, chain, jump rings, eyelets, bails, and other common findings.
How to Choose the Right Drill Bit Size for Jewelry
The basic rule is simple: the hole should be slightly larger than the material that needs to pass through it.
In many cases, adding about 0.5 mm - 1.0mm to the material diameter gives a more comfortable fit. A tighter hole may work for delicate designs, while pendants meant for thicker cord, wrapped wire, or connector fittings often need more clearance.
Important Note on Standard vs. Custom Drill Bit Sizes
The tables below sometimes reference hole sizes in 0.1 mm ranges to show the ideal fit for specific jewelry applications.
However, Gunther’s standard drill bits are typically offered in 0.5 mm increments, such as 1.0 mm, 1.5 mm, 2.0 mm, 2.5 mm, and 3.0 mm.
We can also manufacture custom drill bits in 0.1 mm increments when a tighter match is needed. Custom bits are a great option when precision matters, but they are usually more expensive and take longer to arrive. If your project allows for a little flexibility, it is often simpler and more economical to size up to the next standard drill bit size.
Table 1: Wire Gauge to Drill Bit Size
| Wire Gauge (AWG) | Wire Diameter | Recommended Drill Bit | Common Use |
|---|---|---|---|
| 30 gauge | 0.25mm | 0.7mm | Micro bead work, ultra-delicate wrapping |
| 28 gauge | 0.32mm | 0.8mm – 1.0mm | Delicate wrapping, seed beads |
| 26 gauge | 0.40mm | 1.0mm | Fine bead work, small pendants |
| 24 gauge | 0.51mm | 1.0mm – 1.2mm | Standard bead wire, light pendants |
| 22 gauge | 0.64mm | 1.2mm – 1.5mm | Most popular jewelry wire size |
| 21 gauge | 0.72mm | 1.5mm | Wire wrapping, medium stones |
| 20 gauge | 0.81mm | 1.5mm – 2.0mm | Medium pendants, wrapped loops |
| 18 gauge | 1.02mm | 2.0mm | Heavy pendants, structural wrapping |
| 16 gauge | 1.29mm | 2.0mm – 2.5mm | Large focal stones, bangles |
| 14 gauge | 1.63mm | 2.5mm – 3.0mm | Heavy statement pieces |
| 12 gauge | 2.05mm | 3.0mm | Thick structural wire, large stones |
| 10 gauge | 2.59mm | 3.5mm | Industrial / oversized pieces |
Rule of thumb: add 0.5mm to wire diameter for comfortable threading clearance.
Table 2: Cord Type to Drill Bit Size
| Cord Type | Cord Diameter | Recommended Drill Bit | Common Use |
|---|---|---|---|
| Ultra-fine nylon thread (Nymo O) | 0.15mm | 0.7mm | Micro beads, finest bead weaving |
| Nylon beading thread (Nymo B) | 0.20mm | 0.7mm | Seed beads, bead weaving |
| Silk thread – Griffin Size 0 | 0.30mm | 0.8mm – 1.0mm | Pearl knotting, delicate beads |
| Nylon/silk thread – Griffin Size 2 | 0.45mm | 1.0mm | Fine bead stringing |
| Silk thread – Griffin Size 4 | 0.60mm | 1.2mm | Standard pearl necklaces |
| Silk thread – Griffin Size 6 | 0.70mm | 1.2mm – 1.5mm | Medium pearls, gemstone beads |
| Silk thread – Griffin Size 8 | 0.80mm | 1.5mm | Larger pearls, heavier beads |
| Silk thread – Griffin Size 10 | 0.90mm | 1.5mm | Heavy pearl knotting |
| Silk thread – Griffin Size 16 | 1.05mm | 1.5mm – 2.0mm | Largest pearls, heavy knotting |
| Elastic cord (fine) | 0.5mm | 1.0mm – 1.2mm | Stretch bracelets, small beads |
| Elastic cord (standard) | 0.8mm | 1.5mm | Most stretch bracelets |
| Elastic cord (heavy) | 1.0mm | 1.5mm – 2.0mm | Large bead stretch jewelry |
| Waxed linen cord | 0.8mm | 1.5mm | Micro macramé pendants |
| Leather cord (fine) | 1.0mm | 1.5mm – 2.0mm | Minimalist pendants |
| Leather cord (standard) | 1.5mm | 2.0mm – 2.5mm | Most leather jewelry |
| Leather cord (thick) | 2.0mm | 2.5mm – 3.0mm | Bold statement necklaces |
| Hemp cord (fine / 20lb) | 1.0mm | 1.5mm – 2.0mm | Natural/boho jewelry |
| Hemp cord (standard) | 2.0mm | 2.5mm – 3.0mm | Macramé, chunky designs |
| Satin rattail (1mm) | 1.0mm | 1.5mm – 2.0mm | Knotted necklaces, kumihimo |
| Satin rattail (2mm) | 2.0mm | 2.5mm – 3.0mm | Statement cord necklaces |
| Paracord | 4.0mm | 4.5mm – 5.0mm | Rugged/outdoor jewelry |
Table 3: Chain Type to Drill Bit Size
| Chain Type | Typical Link Wire Gauge | Connector Jump Ring Size | Recommended Drill Bit |
|---|---|---|---|
| Finest cable / trace chain | 28–30 gauge | 2mm–3mm OD / 28–30g wire | 0.7mm |
| Delicate cable chain | 26–28 gauge | 3mm–4mm OD / 22–24g wire | 1.0mm – 1.2mm |
| Standard cable chain | 22–24 gauge | 4mm OD / 20–22g wire | 1.5mm |
| Figaro chain | 20–22 gauge | 4mm–5mm OD / 20g wire | 1.5mm – 2.0mm |
| Rolo / belcher chain | 18–20 gauge | 5mm OD / 18g wire | 2.0mm |
| Curb chain (fine) | 18–20 gauge | 5mm OD / 18g wire | 2.0mm |
| Curb chain (heavy) | 16–18 gauge | 6mm OD / 16–18g wire | 2.0mm – 2.5mm |
| Box chain | 20 gauge | 4mm–5mm OD / 20g wire | 1.5mm – 2.0mm |
| Snake chain | N/A – rigid | End connector 2.0mm pin | 2.5mm |
| Ball chain (1.5mm) | N/A | Direct thread through stone | 2.0mm |
| Ball chain (2.4mm) | N/A | Direct thread through stone | 3.0mm |
| Wheat / spiga chain | 20–22 gauge | 4mm OD / 20g wire | 1.5mm – 2.0mm |
Pro tip: When drilling for chain, match your drill bit to the jump ring wire gauge or connector fitting that must pass through the hole — not just the chain itself.
Table 4: Common Findings to Drill Bit Size
| Finding Type | Post / Pin Diameter | Recommended Drill Bit | Notes |
|---|---|---|---|
| Micro eyelet (ultra-fine) | 0.5mm post | 0.7mm | Finest pendant eyelets, micro stones |
| Standard eyelet (small) | 1.0mm post | 1.5mm | Common in lightweight pendants |
| Standard eyelet (medium) | 1.5mm post | 2.0mm | Most versatile pendant eyelet |
| Standard eyelet (large) | 2.0mm post | 2.5mm | Heavy stones, large focal pieces |
| Bail (pinch style) | N/A – clamps on | No drilling needed | Attaches without a hole |
| Bail (glue-in, 2mm pin) | 2.0mm pin | 2.5mm | Glue-set bails for pendants |
| Bail (glue-in, 3mm pin) | 3.0mm pin | 3.5mm | Larger decorative bails |
| Bail (screw-top) | 2.0mm–3.0mm | 2.5mm – 3.5mm | Adjustable screw-set bails |
| Jump ring (18g / 4mm OD) | 1.0mm wire | 1.5mm | Standard connector ring |
| Jump ring (16g / 5mm OD) | 1.3mm wire | 2.0mm | Medium connector, heavier chains |
| Jump ring (14g / 6mm OD) | 1.6mm wire | 2.5mm | Heavy statement pieces |
| Head pin (24g) | 0.51mm | 1.0mm – 1.2mm | Delicate dangle earrings |
| Head pin (22g) | 0.64mm | 1.2mm – 1.5mm | Standard dangle earrings |
| Head pin (20g) | 0.81mm | 1.5mm – 2.0mm | Heavier dangle pieces |
| Eye pin (21g) | 0.72mm | 1.5mm | Linked bead chain components |
| Pendant connector (lobster clasp pin) | 1.5mm–2.0mm | 2.0mm – 2.5mm | Interchangeable pendant systems |
| Leather end crimp (4mm) | 4.0mm opening | 4.5mm – 5.0mm | For thick cord finishes |
Quick Reference: Universal Sizing Chart
| Hole Size | Best For |
|---|---|
| 0.7mm | Gunther's smallest bit — micro beads, seed pearls, ultra-fine thread, 30g wire, finest chain connectors |
| 0.7mm – 1.0mm | Ultra-fine thread, 28–26g wire, seed beads |
| 1.0mm – 1.5mm | Fine wire (24–22g), silk cord, thin leather |
| 1.5mm – 2.0mm | Standard wire (20–18g), most cord, jump rings |
| 2.0mm – 2.5mm | Heavy wire (16g), thick cord, standard bails |
| 2.5mm – 3.5mm | Large findings, glue-in bails, heavy chain connectors |
| 4.0mm+ | Paracord, leather end crimps, large decorative holes |
Standard Size or Custom Size: Which Should You Choose?
If your project has some flexibility, choosing the next standard drill bit size is often the best option. Standard sizes are usually the fastest and most economical choice, and for many jewelry applications they work perfectly well.
If your design requires a tighter fit — for example, when matching a very specific wire, cord, or finding diameter — Gunther can produce custom drill bits in 0.1 mm increments. That extra precision can be valuable, but it typically comes with added cost and longer lead times.
If your project allows it, standard sizes are often the simplest solution. If precision is critical, custom sizing is available.
Final Thoughts
Choosing the right drill bit size for jewelry making is not just about drilling a hole — it is about making sure your finished piece works the way you intend. The right size can make threading easier, improve the appearance of the finished design, and reduce the risk of wasted time or damaged material.
Use this guide as a practical reference when planning drilled stone jewelry with wire, cord, chain, jump rings, eyelets, bails, and other common findings. And when the ideal size falls between standard increments, Gunther can help with a custom solution.
FAQs - Frequently Asked Questions
What size drill bit should I use for jewelry making?
The right drill bit size depends on what needs to pass through the hole. In general, the hole should be slightly larger than the wire, cord, chain connector, or finding being used. For many jewelry applications, adding about 0.5 mm of clearance creates a more comfortable fit.
What size drill bit do I need for 20 gauge jewelry wire?
For 20 gauge wire with a diameter of about 0.81 mm, a practical drill bit size is usually 1.5 mm to 2.0 mm. The exact size depends on how much clearance you want and whether the wire needs to move freely through the hole.
What size hole do I need for 1 mm cord?
For 1 mm cord, a hole size of about 1.5 mm to 2.0 mm is usually a good working range. This helps the cord pass through more easily, especially if the material has texture, compression, or slight variation in thickness.
Should I match the drill bit to the chain or the jump ring?
In most cases, you should match the drill bit to the jump ring, connector, or end fitting that has to pass through the hole, not just the chain itself. This is especially important for pendants and drilled stones where the connector determines the minimum usable hole size. Your draft already makes this point clearly.
Do Gunther standard drill bits come in every size listed in this guide?
Not always. Some sizes in this guide are shown in 0.1 mm ranges to help identify the ideal fit for a project. Gunther’s standard drill bits are typically offered in 0.5 mm increments, such as 1.0 mm, 1.5 mm, 2.0 mm, and 2.5 mm.
Can Gunther make custom drill bits in exact sizes?
Yes. Gunther can manufacture custom drill bits in 0.1 mm increments when a closer size match is needed. Custom sizes are useful when precision matters, but they are usually more expensive and take longer to arrive than standard sizes.
Is it better to order a custom bit or size up to the next standard size?
If your project allows for a little flexibility, it is often easier and more economical to size up to the next standard drill bit size. If the fit needs to be more exact, a custom bit may be the better option.
What is the smallest drill bit size in this guide?
The smallest size referenced in this guide is 0.7 mm, which is useful for micro beads, seed pearls, ultra-fine thread, and very delicate jewelry applications. That sizing appears in your quick-reference chart and wire table.
What kind of drill bits are best for drilling stone jewelry?
For hard materials such as stone and gemstone, makers commonly use diamond drill bits. Cooling and proper drilling technique also matter when drilling stone. Google’s structured data docs don’t govern that point, but if you want, I can also build a short “how to drill stone safely” section for this post.