Annular Cutter FAQ

An annular cutter is a special type of drill used to drill through steel. Like a hole saw for wood, the annular cutter only cuts the outer edge of the hole.

It can produce precise burr-free holes to close tolerances without the need for pre-drilling or step drilling. It can drill larger holes with less force and time required than a standard twist drill bit. As it turns, the tool produces chips from the outer cutting edge and after cutting the hole, the "chips" (rounded pieces of steel in the centre of the tool) come off.

Why use an annular cutter?

Annular cutters offer excellent holemaking capabilities. They cut faster, last longer, produce better hole finishes, true round holes with very tight tolerances, can be resharpened and drilled with less power and torque.

HSS Annular Cutter 

Which annular cutter do I use?

Use this chart to determine which annular cutter to use. Your choice of cutter will depend on the diameter of the hole, the depth of cut and the type of material. Various annular cutters are designed to cut the following materials.

- Carbon steel

- stainless steel

- Aluminium - carbide, e.g. titanium

- Hastelloy

What are diameters and depths?

When sizing tools, they are measured by depth and diameter. If you look at the actual cutter, the depth is actually longer than the rated depth (a 1" tool is actually 1-1/4") as this ensures that the tool can be drilled all the way through the hole and allows for additional lengths of resharpening.

TCT Annular Cutter

What is cutter geometry?

The angle on the cutting tooth has a significant impact on the performance of the cutter. A more precise angle increases tool life and accuracy.

Cutters are available in four different tooth geometries.

- 2 Angle

- 2 & 3 angles

- Stack-Cut

- Industrial

What are standard & stacked cutting geometries?

Most annular cutters come with a standard geometry. These tools are designed to cut a piece of steel. They provide the fastest, cleanest holes and produce a slug that looks like a "bowler hat". When the job requires drilling two or more pieces of steel, a tool with a stacked cutting geometry must be used. The cutting teeth cut from the inside out to produce a round plunger.

Uncoated versus coated annular cutters?

For 80% of applications, standard HSS annular cutters will work. There is no additional benefit to using coated or carbide cutters in these applications. The hard material is where the benefit of using coated or carbide cutters comes into play, increasing cutter life.

HSS Annular Cutter 

What causes a cutter to dull or break?

The main cause of cutters damage or premature dulling is too slow a feed rate. Slow feed rates shorten the life of the cutter. Using firm, consistent feed pressure throughout the cutting process will maximise performance and extend cutter life. You want to hear the drilling motor working and the cutter producing long strips of chips pulled out of the hole. Look for bird's nests around the tool.

Blue chips = big problem

(coolant system is blocked or pushed too hard)

Make sure you have the correct cutter for the material. Stacked cuts in multiple layers.

The second cause of cutter breakage is movement of the drill or workpiece. If the drill and the material do not remain rigid, the cutter wall can easily break.

Can I make customised cutters?

Absolutely! Zhuotuo can solve your hole machining problems with creative solutions that help you get the job done, faster and at a lower cost. We have provided unique holemaking solutions to thousands of customers. Feel free to contact us and tell us about your drilling challenges.