9 Best Diamond Drill Bits for Stone Jewelry | The Clear Standouts

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The 1.5mm specialist that comes with the collet already in the box, so setup is a ten-second job.

For jewelry makers chasing a specific hole size, this is the pick. The 1.5mm cutting diameter is the standard for thin sea glass pendants and small beadwork, and the set packs twenty of them. What separates it from the tweezers-and-guesswork approach is the included collet — that matching collar lets the round shank seat securely in rotary tools, flex shafts, and compatible drills without you ordering anything extra. A split point tip with diamond coating reduces the walking you get when a bit skates across a polished surface, and a 135-degree cutting angle bites consistently at the start of a hole. If your projects are all small and delicate — beadwork, tiny shells, fused glass drops — this is the diameter you want repeated twenty times.

Owners drilling glass and shells for jewelry lean on these and keep buying them, and the quality of the bits is the reason the set holds up over repeat sessions. The trade-off is the tip itself. These are small bits, and small bits break under sideways pressure — one buyer’s honest note is that you need soft pressure, especially on the smaller ones. The other piece of honest feedback is that some users find the fit with certain Dremel models less snug than expected, even though many others report a clean handshake. Check the collet seating before you commit to a long drilling run.

Speed matters more than most people realize here. Reviewers get the cleanest holes at 80-1200 RPM with the workpiece fully submerged and almost no downward pressure. Follow that and the bits reward you with straight, smooth holes; rush it and the smaller tips will fracture. It is a set that wants a light hand and pays you back for one.

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Ten bits at each of 1mm, 2mm, and 3mm — three hole sizes in one case for under thirty dollars.

Where the 30-piece Drilax set gives you two diameters, this SI FANG set gives you three: ten bits each at 1mm, 2mm, and 3mm. That trio maps neatly onto real jewelry work — the 1mm for the most delicate materials where standard bits just crack or wander, the 2mm for the everyday pendant hole, and the 3mm for enlarging a hole you already started. All thirty share a 1/8-inch shank with a tolerance the maker lists at ±0.02 mm, so they seat in Dremel grinders and most rotary tools without an adapter. The manufacturer also lists straightness of ≤ 0.05 mm for the bits, which is the spec that keeps a hole from drifting off-center as you drill.

The set is aimed squarely at hobbyists drilling multiple materials — sea glass, stained glass, soft stone, ceramics, porcelain, resin, quartz, and shell all appear on the maker’s list. If you want a single case that covers a mixed-material bench without buying three separate packs, this is the value play.

One important thing to flag: a couple of experienced users note these bits have flat heads and function more like grinding or etching tools than pointed drills, so if you are expecting a sharp-tipped boring bit, adjust your expectation and start with a smaller size, then step up. The maker recommends the 45-degree start growing to 90 degrees with no hard pushing, and reviewers drilling fused glass confirm that sequence produces clean, crack-free holes. For repeated heavy production drilling, look elsewhere — this set is built for one-off and small-batch projects.

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Two German-made diamond twist drills for clearing tiny holes in coral, turquoise, and pearl.

This is a two-piece set for a specific job: cleaning out and opening tiny bore holes in coral, turquoise, pearl, and other precious stones that already have a passage started. The bits are 0.8mm and 1.2mm, made in Germany with natural diamond dust for the cutting surface, and the twist design is meant for reaming existing small holes rather than boring fresh ones in solid rock. The 3/32-inch (2.35mm) shank is the Proxxon standard, so it fits Proxxon tools and any rotary tool with the matching collet — this is not the 1/8-inch universal fit that dominates the hobby market.

The strength here is precision on hard, valuable material. A fine tip that slips through a pearl or a piece of turquoise without shattering the surrounding surface is worth paying more per bit for, and the German manufacturer’s precision is the marketing point on the tin. If you are cleaning bezel holes, stringing pearls, or opening passages in soft-stone carvings, these tiny diameters are the ones that work.

What you need to know before buying is that this is a two-bit set at a premium-tier price, and the small tip is genuinely fragile — feedback includes a tip snapping on first use. The larger of the two bits stands up better to the job. For drilling glass specifically, this set gets mixed word of mouth from buyers who expected more from it. Use water to keep the tip cool and to avoid inhaling stone dust — the underwater drilling method works well on small crystals.

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Lasco’s 2.5mm workhorse for sea-glass artists who measure projects in hundreds of holes.

Sea glass artists burn through bits, and this Lasco 10-pack exists for exactly that reality. Each bit cuts a 2.5mm hole — the middle ground between the delicate 1.5mm and the chunky 3mm — with a straight shank, stainless steel body, and 100% diamond coating. The bits are made in the USA by Lasco Diamond Products, and the price per bit lands friendly enough to treat each one as a consumable rather than a precious tool. Running them on a drill press with a water bath, reviewers report getting tens of holes out of a single bit before it dulls.

What makes this set distinctive is the durability on softer materials. Drilling ribbed glass, sea glass, pottery, ivory, and soft stone is where these Lasco bits shine — one reviewer noted 80-plus sea glass pieces on a single bit before needing a replacement. That stamina on soft, brittle stock is the reason stained-glass hobbyists keep reordering them. The straight shank works with the same rotary tools and presses you already have, and the 135-degree cutting angle is a familiar geometry that most hobbyists know how to run.

The recurring gripe is bending rather than dulling. A few buyers have pulled a bit out of the tube with a slight curve in the shank, so it is worth rolling each bit on a flat surface before you mount it — a bent bit will drill a sloppy, off-center hole. And on hard agate specifically, these softer-made bits do not hold up as well as they do on sea glass, so if your whole bench is hard stone, look at the 2.0mm or 3mm options instead.

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A stainless-shanked Lasco bit that chews through agate and hard gemstone where softer bits stall.

Where the 2.5mm Lasco set is built for soft sea glass, this 2.0mm version is built for the harder stuff. Same maker, same USA production, same stainless steel shank with a diamond coating — but sized to a 2mm cutting diameter that suits dense gemstones, agate slices, and hard river rock. If your bench leans toward hard material rather than sea glass, this is the Lasco bit that keeps cutting after the softer options dull.

Buyers report 30-plus holes through hard agate and gemstone on one bit, submerged in water, outlasting budget coated bits. A stained-glass artist running one tube on the drill press reported a single bit lasting a full month of heavy use. One user counted 50 holes on a single bit and reordered immediately. Run it with ice water and the drill-pause-drill cadence and the coating rewards you with consistent clean holes.

The honest note: not every buyer gets that performance. One buyer mentioned a bit that did not drill glass well at all, and questions the made-in-USA claim on the pack. Given how consistent the reviews are across the rest of the set, that reads more like an outlier unit than a pattern — but it is worth buying from the listing that lets you return easily. Stick to water cooling and short bursts and the strip holds up.

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Ten 1.5mm core bits that hold their edge when you keep them cool.

For 1.5mm jewelry holes — the diameter that fits a pinch bail or 18-gauge wire — this Lasco pack is the crowd-favorite among experienced lapidary artists. Ten bits, each with a stainless steel shank coated in 100% diamond with no filler abrasives, sized at a 1.5mm cutting diameter. The set performs best on a drill press, where a steadier hand than a rotary tool alone gives keeps the small bit from wandering. If you already own a Dremel press stand, this set is the natural pair.

The reason this survives repeat buying is the tip temperature. Reviewers who have tried other diamond bits say these resist the heat burnout that kills competing brands. Underwater drilling on a drill press yields roughly 20 clean 1.5mm holes per bit with no blowout on the backside. Buyers also mention fitting 18-gauge wire and pinch bails straight through.

One caveat: the set wants water and light pressure, and running it dry burns the diamond coating faster than the reviews imply. On hard stone specifically, the 1.5mm diameter is too small for bulk drilling — you want the 2mm or 2.5mm Lasco for that. And while the pack lives up to its made-in-USA claim, the general durability picture is mixed because it is limited by the small bit size itself.

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A starter set of ten 1.5mm and 2mm bits with the collets already sorted.

This Drilax pack is the low-entry option — ten bits split between 1.5mm and 2mm, plus two collets included so the bits mount directly onto a rotary tool without any extra purchase. A 135-degree cutting angle is the standard that most hobbyists know how to run, and the diamond finish is spec’d for small, precise hole work in glass, stone, and shells. If you are starting out and want to try a couple of hole sizes before committing to a bigger set, this is the low-risk way in.

The strength is small-hole versatility in brittle materials. The set is aimed at beading, pendants, sea glass, and shells — exactly the stock where a controlled hole matters more than drilling speed. Buyers find the set effective on sea shells and glass when mounted with cooling, and a couple of owners note it holds up better than similarly-priced diamond bits bought locally. That value-per-bit is what makes it worth a look for the first project.

The honest limit is durability on hard material. Diamond coating on fine small bits wears quickly — one user found they stalled out on hard fluorite, and another found them too soft for river rock. That is not a defect; it is what fine diamond bits do on dense material. If your work is soft sea glass, glass, or shell, this set is a sensible low-cost entry; if you intend to drill hard gemstone repeatedly, spend up to a set with a reinforced tip.