Deburring Tools

A burr is the ridge of displaced material left behind wherever a cutting tool exits the workpiece: the lip around a drilled hole, the feathered edge along one side of a milled slot, the pip on a parted-off face. A deburring tool removes it by shearing it off rather than grinding it away, which is why it leaves a controlled chamfer instead of a rounded, scratched edge.

Burrs matter for more than tidiness:

• Safety — a burr is a cut hazard on every part anyone handles downstream.
• Fit — it stops mating faces seating, so an assembly measures out of tolerance even though both parts were made correctly.
• Finishing — burrs trap swarf and coolant, which contaminates plating, anodising and paint.
• Fatigue — on a loaded part a burr is a stress raiser, and stress raisers are where cracks start.
• Measurement — a burr on an edge will throw a micrometer reading before it throws anything else.

Most deburring tools also cut a small chamfer as they go, typically a few tenths of a millimetre, which is usually what a drawing means when it calls for a broken edge.

Four families cover almost all workshop deburring, and they are not interchangeable:

• Hand deburring tools — a handle holding a small replaceable blade. Most use a swivel head that pivots to follow the edge, so it tracks a curve or a hole rim without you re-gripping. This is the default for one-off edges, finished surfaces and anywhere a slip would scrap the part. Blades are consumable; the handle lasts years.
• Zero-flute and single-flute countersinks — for hole edges. A single cutting edge across the cone means there is nothing to set up a chatter pattern, so you get a clean chamfer in one pass. Use them in a drill, mill, lathe tailstock or by hand. Available 60°, 82°, 90° and 100°, in HSS-E and TiN coated.
• Tungsten carbide burrs — rotary cutters for a die grinder, for weld dressing, casting flash, opening out slots and any stock removal beyond what a blade can shift.
• Scrapers and specials — hollow scrapers for flat faces and bores, key-way blades for slots, and 60°/90° heads for chamfering bar ends.

If you don't already own a handle, a deburring set bundles one with a spread of blades and works out cheaper than buying the pieces separately.

Two things decide it: the shank size your handle takes, and the kind of burr you are removing. Ø3.2 mm is the standard size and fits most handles. Ø2.6 mm P-series blades are the light-duty size used by the Econo handles, and Ø6 mm R-series blades are for heavy edges on larger work.

The CP Gratex range is coded by application rather than by size, which makes selection quick once you know the codes:

Several blades are handed. C-10, C-30, C-60 and C-101 are right-hand; C-15, C-20, P-2 and the ceramic C-1 are ambidextrous; P-3 is left-hand. If a shared tool drawer has left-handed users in it, the ambidextrous blades are worth standardising on. Every blade is laser-marked with its code, so they stay identifiable once they are out of the packet.

If you're not sure where to start: C-10 for general edges, C-20 for cast iron and brass, C-15 for stainless, C-101 for small holes. Those four cover most of what comes off a machine. Browse all CP Gratex blades →

It depends which edge of the hole you mean.

Hole entry. A zero-flute or single-flute countersink is the fastest and cleanest answer. Because it cuts on one edge there is no chatter, so it leaves a smooth chamfer in a single pass with no follow-up work. Pick the angle to match what the hole is for: 90° is the general-purpose metric default, 82° and 100° suit imperial fastener heads, and 60° is used for light lead-ins. Head diameter must be larger than the hole. HSS-E (5% cobalt, M35) versions handle stainless and harder material; TiN-coated versions last longer in production.

Hole exit, where you can reach it. Same countersink from the other side, or a swivel-blade hand tool run round the rim.

Hole exit, where you cannot reach it. This is what back-deburring blades are for. A C-60 (or P-6 in the light-duty size) feeds through the hole, and the swivel head flips over and cuts on the pull stroke as you draw it back. C-60 works on sheet up to 20 mm, P-6 up to 15 mm.

Both edges at once. A C-30 blade deburrs the inner and outer edge of a sheet-metal hole in one pass, up to 10 mm thick — a real time-saver on punched or laser-cut sheet with a lot of holes.

Small and micro holes. A C-101 goes down to Ø1.5 mm, which is smaller than any countersink will practically manage.

Past roughly twenty holes, put the countersink in a drill chuck or run it as a tool in the CNC program. It will beat any hand tool on both speed and consistency.

Reach for a carbide burr when there is more material to remove than a blade will shift: weld beads, casting flash, hard scale, opening out a slot, blending a radius. They run in a die grinder or flexible-shaft tool and cut on the side and, on some shapes, the end. Diameters run from 3 mm to 16 mm.

The cut is the tooth pattern, and getting it wrong is the usual reason a burr disappoints:

• Single cut — one spiral row of teeth. Coarser and more aggressive, throws a long chip. Best for fast stock removal on steel, stainless and cast iron.
• Double cut (cross cut) — a second row cut across the first. Smaller chips, smoother finish, less grabbing and easier to control. The general-purpose choice, and the one to buy if you are only buying one.
• Aluminium cut — wide, deeply gulleted teeth designed to clear soft, gummy swarf instead of packing up with it. Use on aluminium, brass, copper and plastic. A double-cut burr will clog solid in aluminium within seconds; an aluminium-cut burr is not a nicety here, it is the difference between working and not.

The shape follows the geometry you are working into. The Vortex range covers Type A (cylinder, no end cut), B (cylinder with end cut), C (ball-nose cylinder), D (ball nose), E (oval), F (ball-nose tree), G (pointed tree), H (flame), J and K (countersink), L (ball-nose cone), M (cone) and N (inverted cone). In practice: D for blending a radius, B when you need to plunge as well as cut sideways, G to get into a corner, N for an undercut, K for chamfering a hole.

Let the burr do the work at speed rather than leaning on it — carbide chips if you push it into a stall, and heat is what kills the edge.

Most workshops need both, and the split is about control versus throughput.

Hand tools win on control. A swivel blade cuts on the pull, so you feel the burr go and you feel when it has gone. Nothing is spinning, so a slip marks nothing. That matters on one-offs, on finished or plated surfaces, on thin material, on anything already at final size, and on expensive parts where a scrapped component costs more than the hour saved. Hand tools also need no fixturing, no power and no setup — you pick the part up and do it.

Powered tools win on repetition. Once you are past around twenty identical features, a countersink in a drill chuck or a burr in a die grinder is faster and more consistent than any hand can be, and it does not get tired at the end of a shift.

On CNC, deburr in-cycle. A zero-flute countersink runs perfectly happily as a tool in the program. Chamfering the holes before the part comes off the machine removes a whole manual operation and guarantees every part gets it — which hand deburring, honestly, never does.

The practical setup for a small shop: a handle and a spread of blades on the bench, a countersink set by the pillar drill, and a die grinder with a couple of burrs for the jobs neither will touch.

Stainless steel and harder alloys. Stainless work-hardens, so repeated light scraping over the same spot makes the material harder and the job worse. Take one continuous cut with a sharp blade. The C-15 is the blade specifically intended for stainless; on volume the multi-cutting-edge MC equivalents last considerably longer. For hole work use HSS-E (M35, 5% cobalt) countersinks rather than plain HSS, and for carbide burrs choose single cut. Above 35 HRC move to a carbide-edged blade, which is rated to 60 HRC.

Aluminium, brass and copper. Soft and gummy — the problem is material welding itself to the tool rather than tool wear. Use aluminium-cut carbide burrs, which have the gullet space to clear the chip. For blades, a C-10 handles the spiral chip that aluminium and copper produce; brass throws a brittle burr instead, so a C-20 suits it better. TiN-coated countersinks resist built-up edge.

Plastics, composites and coated parts. Use a ceramic blade. Ceramic will not transfer metal onto the surface or leave a grey mark on a white part, it is non-conductive and non-sparking, and it holds its edge far longer than steel in glass-filled and mineral-filled plastics that would blunt HSS in minutes. Keep the pressure light: heat is what melts a plastic burr back onto the part instead of removing it.

Cast iron. Brittle burrs, so C-20 or MC-20. Expect faster wear across the board — cast iron is dry and abrasive and it is hard on everything.