The Short Answer
An annular cutter cuts only the ring (annulus) of a hole and ejects a solid centre slug, so it uses roughly one-third the power and feed force of a twist drill of the same diameter — and drills large holes 3-4x faster. That single mechanical difference is why a portable magnetic-base drill with an annular cutter outperforms a far more powerful drill press fitted with a twist drill on every large hole in steel plate.
All three tools make a round hole, but they are not interchangeable. The twist drill grinds the entire hole volume into chips and owns small holes and any depth. The annular cutter (the mag-drill core cutter) machines only the thin ring and ejects a slug, and owns clean large holes in thick steel. The hole saw is also a ring cut, but with thin gulleted teeth on a shallow cup, and owns thin sheet, tube, and wood in a hand drill. Pick by what you are cutting and on what machine, not by which one is “best”.
How Each Tool Removes Material
The defining difference is how much of the hole becomes chips: an annular cutter turns only ~25-30% of the hole volume into chips and leaves the rest as a solid slug, while a twist drill grinds 100% of the hole volume into chips.
- Annular cutter — cuts a thin ring at the outer diameter with multiple teeth and leaves the centre intact as a solid plug. As the cutter reaches full depth, the spring-loaded pilot pin ejects that slug. Only the narrow annulus is machined, so roughly 25-30% of the hole volume becomes chips and the rest leaves as one reusable disc of metal.
- Twist drill — its two lips and chisel edge machine the entire cross-section of the hole, so 100% of the hole volume is ground into chips. Nothing is left as a slug. That is why the power and feed force climb so steeply with diameter — the tool is removing every cubic millimetre of the hole.
- Hole saw — also a ring cut that leaves a centre slug, but the cut is made by thin, gulleted, widely-spaced teeth (often TCT) on a shallow cup. The thin kerf and aggressive gullets are tuned for thin sheet, tube, wood, and plastic, not for shearing a deep, precise wall in thick steel.
Power, Feed Force, and Speed
Because most of the material leaves as a slug rather than as chips, an annular cutter needs only about one-third of the cutting power and feed force of a same-diameter twist drill. Removing roughly a third of the material does roughly a third of the work, and the saving grows with diameter.
This is exactly why a portable magnetic-base drill can bore a 50mm hole that a hand drill never could. The hand drill has neither the power nor the steady feed to push a 50mm twist drill through plate, and the operator cannot supply the thrust by arm. The mag drill, feeding a 50mm annular cutter that only machines the ring, does it comfortably on a fraction of the power — the slug carries most of the material out for free.
On speed, the annular cutter is typically 3-4x faster than a twist drill once the hole is above about 12mm. A large twist-drilled hole has to be built up: centre-punch, pilot drill, then step up through one or more intermediate sizes, each pass taking time and re-fixturing. The annular cutter skips all of that — one pass, no pilot drill, no step-up sequence — so a hole that takes a twist-drill sequence several minutes drops to seconds.
Hole Quality and Burrs
An annular cutter leaves a burr-free, smooth, reamed-quality wall to near-H tolerance in a single pass, where a large twist-drilled hole needs pilot and step drilling and still throws an exit burr.
The reason is the cutting action. The annular cutter shears the wall with many small teeth in a continuous, low-force ring cut, so the wall comes out smooth and the breakthrough leaves almost no burr — often clean enough to bolt or ream straight away. A twist drill drives its full chisel edge and both lips through the metal, deforming and tearing it at breakthrough, which raises a heavy exit burr that has to be removed in a separate deburring step. Stepped twist-drilling can also leave a ridge at each size change. A hole saw, by contrast, leaves a comparatively rough wall — fine for a clearance hole in sheet, but not a finished bearing or bolt surface. For any hole that has to be accurate and clean, the annular cutter removes an entire finishing operation.
Depth Limit, Machine, and Rigidity
An annular cutter's reach is capped by its depth of cut — standard 25 or 50mm, long-reach versions 75 or 100mm — and for anything deeper than that the twist drill wins outright.
A twist drill can be made or extended to almost any depth, so deep holes, blind holes, and through-holes in thick sections beyond a cutter's DOC belong to it. A hole saw is depth-limited too, but more tightly: it can only cut material thinner than its cup is deep, so it is a thin-material tool by construction.
The other hard constraint is the machine. An annular cutter needs a rigid machine — a magnetic-base drill, drill press, or mill — not a hand drill. It only engages at its outer ring, so it must be held square and fed steadily or the teeth chatter and chip. A twist drill is far more forgiving and runs in anything from a hand drill to a CNC. A hole saw is happy in a hand drill, which is a large part of its appeal. Matching the tool to the available machine is as important as matching it to the material: an annular cutter on a hand drill is the single most common misuse in this category.
Diameter, Thickness, and Cost-per-Hole
An annular cutter owns roughly Ø12-150mm holes in plate from about 3mm thick up to the cutter depth of cut; below ~3mm sheet the slug barely forms and a step drill or hole saw is better.
The three tools cover overlapping but distinct windows. The twist drill covers the small end that nothing else reaches — tiny pilot holes and small diameters where there is no slug to speak of — and any depth. The annular cutter covers the mid-to-large diameters in thick steel, its sweet spot, where its speed and finish advantage is largest. The hole saw owns thin sheet and large, shallow holes in soft material, where cutting a deep precise wall is unnecessary and a thin kerf in a hand drill is enough.
On cost-per-hole, the annular cutter is the cheapest option at volume in structural plate despite a higher tool price, because it drills far more holes per hour, needs no deburring, and resharpens. Its higher up-front cost is amortised fast across a production run. For occasional small holes, though, the twist drill is cheaper to own outright — there is no point buying a mag-drill cutter and a rigid machine to make a handful of small holes. Volume and thickness decide it: the annular cutter wins the high-volume thick-plate economics, the twist drill wins the occasional small hole.
Three-Way Comparison Table
The three metal-hole tools side by side on the parameters that decide which to use:
| Parameter | Annular Cutter | Twist Drill | Hole Saw |
|---|---|---|---|
| How it removes material | Cuts a thin ring, ejects a solid slug (~25-30% becomes chips) | Grinds the entire hole volume into chips (100%) | Thin-kerf gulleted ring cut, leaves a slug |
| Relative power / feed force | ~1/3 of a twist drill | Highest (full volume removed) | Low, but only in thin material |
| Speed (Ø > 12mm) | 3-4x faster, single pass, no pilot/steps | Slow — needs pilot + step-up sizes | Fast in thin sheet, slow/poor in thick steel |
| Hole-wall quality | Burr-free, reamed-quality, near-H in one pass | Heavy exit burr; step ridges on big holes | Rough wall, not a finished surface |
| Max depth | Depth of cut: 25/50mm std, 75/100mm long | Effectively any depth | Thinner than the cup depth |
| Best material thickness | ~3mm up to the cutter DOC | Any, incl. very thin and very deep | Thin sheet, tube, wood, plastic |
| Machine required | Rigid: mag-base drill, drill press, or mill | Anything — hand drill to CNC | Hand or cordless drill |
| Typical Ø range | ~Ø12-150mm | Tiny up to ~Ø30mm practical | ~Ø15-150mm in thin material |
| Cost-per-hole at volume | Lowest in structural plate | Cheap to own for occasional small holes | Cheap in thin sheet; poor in thick steel |
Annular cutter vs hole saw — the most-confused pair
Both are ring cuts that leave a centre slug, so they get mixed up constantly — but they are opposite tools. The annular cutter is for thick steel, on a rigid machine (mag drill, drill press, mill), to a precise burr-free wall. The hole saw is for thin sheet, tube, and wood, in a hand drill, to a rough wall. If the steel is thick and the hole must be accurate, it is an annular-cutter job; if the material is thin and a clearance hole will do, it is a hole-saw job.
Choose X When
A one-line rule for each tool, so the choice is unambiguous on the shop floor:
- Choose an annular cutter when the work is thick steel (roughly 6-12mm and up to the cutter depth of cut), the holes are large, the wall has to be clean and burr-free, and a mag-base drill, drill press, or mill is available to hold and feed it square.
- Choose a twist drill when the holes are small, when the hole is deeper than any cutter's depth of cut, or when the only machine is portable or hand-held — it runs in anything and reaches any depth, at the cost of speed and burr on big holes.
- Choose a hole saw when the material is thin sheet, tube, or wood, the hole is large and shallow, precision is not required, and the tool has to run in a hand drill.
Related Procurement Programs
If you are specifying or sourcing the mag-drill cutter line behind this comparison, these cover what buyers ask next.
- Annular Cutters — HSS, Cobalt & TCT Mag-Drill Core Cutters — the full core-cutter line in HSS, M42 cobalt, and brazed carbide, with Weldon shanks, matched pilot pins, and 25/50/75/100mm depths of cut, factory-direct and OEM.
- Top Annular Cutter Manufacturers (2026) — the brand shortlist and OEM sourcing guide for this line.
To match a cutter to your steel thickness, hole sizes, and machine, contact our engineering team.
