Carbide Burr Shapes Explained: Type A, C, D, E, F, G, H, M, N, WRC — Which One Do You Need?

Twenty years of grinding Carbide Burrs teaches you one thing fast: buyers rarely pick the wrong shape because they don't know the shapes exist. They pick the wrong shape because two burrs look almost identical on a screen and behave completely differently in the cut.
A ball and a ball-nose cylinder differ by a few millimetres in a product photo. On a die cavity, one of them polishes a radius and the other digs a crater.
This guide covers all ten standard shapes we manufacture — Type A, C, D, E, F, G, H, M and N, plus WRC — with the geometry, the jobs each one wins, the jobs each one ruins, and the cross-reference codes you need when a customer hands you a competitor's part number and asks for "the same thing".

The rule that saves you from every wrong order

These are two independent decisions and buyers constantly collapse them into one. Get the order right: pick the shape that physically reaches the feature, thenpick the cut style for the material. A Ball Burr and a tree burr in the same double cut behave identically as cutting tools — they simply reach different places. A single cut and a double cut ball burr, same shape, same size, are completely different tools in the hand.

Half of the "this burr is no good" complaints we receive in a year trace back to someone choosing an excellent burr of the wrong shape, or the right shape with the wrong tooth pattern.

More on tooth patterns: Single cut vs double cut vs aluminum cut →

Complete carbide burr shape chart

Read the ISO and ANSI columns carefully — they are not the same letter

How to choose in 30 seconds

Read the feature you need to machine, not the material:

1. Flat surface or straight edge → Type A
2. Internal cavity, hole or internal radius → Type C
3. Blending a wall into a curve, no sharp line → Type D
4. Convex or irregular curved surface → Type E
5. Internal corner needing a radius → Type F
6. Sharp internal corner or narrow slot → Type G
7. Narrow curved pocket, awkward access → Type H
8. Chamfer, bevel or V-groove → Type M
9. Undercut, dovetail or rear-side edge → Type N
10. Weld dressing or joint prep → WRC

If you are buying your first burrs, three shapes cover the majority of general shop work: one Type A for flat work, one Type C ball for radii and holes, and one Type F or Type G for corners. Add a WRC if you do fabrication and welding.

The code trap: why "Type C" means two different things

This is the single most expensive misunderstanding in the burr trade, and it is worth five minutes of your buyer's time.

Two international systems use shape letters, and they disagree on C and D:

So a ball burr is:

• ISO 7755 style D
• ANSI SD
• and, in a great deal of everyday trade usage — including our own catalogue — Type C

The letters are not wrong in either system. They are simply different systems, and a surprising number of catalogues mix them without saying so.

Speed: match RPM to head diameter, not to habit

The bigger the head, the lower the safe speed — the teeth at the outer edge of a large burr travel much faster than those on a small one at the same RPM. Overspeeding a large head is how carbide heads fail, and a failing burr sheds teeth at high velocity.

For sizes between these, work between the figures. For extended-shank burrs, run at the lower end regardless of head size — the extra shank length cuts rigidity, and vibration is what breaks tools.

These are starting ranges, not guarantees. Never exceed the maximum RPM marked on the burr or stated in the supplier's data sheet for your specific tool. That rating is the safety limit, and on a brazed carbide head it is not a conservative number.

Then follow the three rules that matter more than any table:

1. Light pressure. Let the tool cut. Pushing hard chips teeth and shortens life.
2. Keep it moving. A burr held in one spot digs in and leaves a mark.
3. Rigid workholding. Vibration, not hardness, is what kills carbide.

Five mistakes we see every year

1. Choosing the shape before the cut style. Reversing the order produces a technically correct burr that behaves nothing like the buyer expected.

2. Ordering by letter code only. Covered above. It causes real, repeated, expensive mistakes.

3. Using a flat-end cylinder where a plunge cut is needed. Type A has no end teeth. The operator burns the work and the tool.

4. Buying one shape and forcing it to do everything. A ball cannot chamfer a straight edge. A cylinder cannot hollow a sphere. Two or three shapes cost a fraction of one ruined workpiece.

5. Treating a pointed tool as a roughing tool. Pointed trees and cones are for access and detail. Used for bulk removal, they chip. Rough with a cylinder or a ball, finish with the point.

Frequently asked questions

What is the most common carbide burr shape?

Cylindrical (Type A) and ball (Type C). Between them they cover flat work, edges, radii, holes and cavities — the majority of general shop work.

What is the difference between Type C and Type D?

Under ISO 7755, C is a ball-nose cylinder and D is a ball. In much everyday trade usage — and in our catalogue — C is the ball and D is the ball-nose cylinder. Always confirm geometry rather than the letter alone.

Which shape removes material fastest?

Shape is only half the answer. A cylindrical burr (Type A) in single cut removes material fastest on steel, because it has the largest continuous cutting edge. In practice the operator's technique and the RPM matter more than the shape.

Which burr should I use for deburring a drilled hole?

A ball (Type C) if you are deburring the inside edge or blending a radius. An oval (Type E) if the hole edge needs blending into a curved surface. A 90° cone if you are producing a countersink.

Which shape is best for weld removal?

WRC (weld reamer cone) first, especially for blending a bead into the plate without gouging beside it. A ball-nose cylinder (Type D) or a flame (Type H) also work well depending on access.

What shape do I need for an internal corner?

Type F (ball-nosed tree) if the corner needs a radius. Type G (pointed tree) if it needs to stay sharp.

Can I use one burr for both steel and aluminium?

No — a steel burr will clog in aluminium within seconds. For non-ferrous work choose an aluminium (open) cut, in whichever shape the feature requires.

Do you make custom shapes and sizes?

Yes. We grind to drawing in Type A, C, D, E, F, G, H, M, N and WRC, in standard and non-standard diameters, with metric or inch shanks, in single cut, double cut and aluminum cut, and in YG6, YG8 and YG10 grades. OEM and private-label packaging available.