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Annular Cutters & Rotabroach - 4

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  1. CS Unitec 4" - Hornet TCT Carbide Cutters 2-3/8" Depth
    Free Shipping at $199+!
    Factory Direct Estimated Shipping in 1-4 Days -Direct from Factory
    Estimated Ship Date: 09/11/2026 - 09/18/2026
    CS Unitec 4" - Hornet TCT Carbide Cutters 2-3/8" Depth
    SKU: CS9-1-2128 C
    $61499
  2. CS Unitec 4" X 2" - 1-1/4" Shank Annular Cutter 6-1-2128
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    Factory Direct Estimated Shipping in 1-4 Days -Direct from Factory
    Estimated Ship Date: 09/11/2026 - 09/18/2026
    CS Unitec 4" X 2" - 1-1/4" Shank Annular Cutter 6-1-2128
    SKU: CS6-1-2128
    $72879
  3. CS Unitec 4" X 3" - 1-1/4" Shank Annular Cutter 6-1-3128
    Free Shipping at $199+!
    Factory Direct Estimated Shipping in 1-4 Days -Direct from Factory
    Estimated Ship Date: 09/11/2026 - 09/18/2026
    CS Unitec 4" X 3" - 1-1/4" Shank Annular Cutter 6-1-3128
    SKU: CS6-1-3128
    $85039
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HSS vs. Carbide Annular Cutters: Choosing the Right Tool

Selecting the right annular cutter is essential for drilling precise, large-diameter holes with minimal effort. At Ohio Power Tool, we offer both High-Speed Steel (HSS) and Carbide-Tipped options to ensure you have the right performance level for your specific metalworking applications.

High-Speed Steel (HSS) Annular Cutters

High-speed steel (HSS) annular cutters are favored for their exceptional versatility and cost-effectiveness. Manufactured from premium high-speed steel, these cutters are ideal for fabrication, construction, and general maintenance tasks involving structural steel, stainless steel, and other non-abrasive metals.

HSS cutters are the top choice when precision and finish are important, but cutting conditions are not excessively demanding, providing a reliable balance of performance and value.

Carbide Tipped Annular Cutters

For more challenging environments, Carbide annular cutters feature specialized carbide tips fused to a durable steel body. This design allows them to maintain sharpness significantly longer and operate at higher cutting speeds than standard HSS.

Carbide cutters excel in high-volume production and are the preferred solution for drilling through hardened steel, cast iron, and abrasive metals that would quickly wear out a standard bit.

Which Cutter is Best for Your Job?

The choice between HSS and Carbide from Ohio Power Tool depends on your material hardness, precision needs, and budget. While HSS offers a cost-effective solution for general drilling, Carbide cutters provide the cutting edge needed for heavy-duty, high-efficiency tasks in the toughest materials.

Annular Cutters & Rotabroach FAQ

What is an annular cutter and how does it work?
An annular cutter (often referred to as a Rotabroach) is a specialized hollow drill bit designed specifically for making holes in metal. Unlike conventional twist drill bits that cut out the entire center of the hole, an annular cutter only cuts the outer perimeter. This leaves a solid center core, or "slug," which requires significantly less horsepower, cuts much faster, and produces a burr-free finish.
What is the difference between HSS and Carbide-Tipped annular cutters?
The primary differences center around material composition, performance under heat, and cost:
  • High-Speed Steel (HSS): Manufactured from premium high-speed steel, these are highly shock-resistant and cost-effective. They offer a great balance of performance and value for general fabrication.
  • Carbide-Tipped: These feature specialized carbide teeth fused to a durable steel body. They handle much higher cutting speeds, resist extreme heat, and maintain their sharpness significantly longer.
When should I choose HSS over Carbide annular cutters?
You should choose HSS annular cutters for everyday construction, general maintenance, and structural steel fabrication involving non-abrasive metals. They are the ideal choice when precision is required on a standard budget and the material being drilled isn't excessively hardened or high-alloy.
When should I choose Carbide-Tipped annular cutters over HSS?
Select Carbide annular cutters for high-volume production lines and when drilling through incredibly tough, abrasive, or hardened metals like cast iron, heavy structural stainless steel, or armored plating. Their ability to run at higher speeds makes them the preferred choice for maximizing efficiency and minimizing tool wear.
Do I need to use cutting fluid or lubrication with annular cutters?
Yes, using a high-quality cutting fluid or lubricant is essential for both HSS and Carbide cutters. Proper lubrication dissipates extreme heat, reduces friction, and clears metal chips from the cutting path. Skipping coolant will quickly dull or shatter the teeth, drastically shortening the tool's lifespan.
Can HSS and Carbide annular cutters be resharpened?
HSS annular cutters can easily be resharpened multiple times using specialized tool grinding machinery to restore their factory edge. While carbide-tipped cutters can technically be resharpened, the process requires highly specialized diamond wheels and is often cost-prohibitive compared to replacing the bit.
What is the role of the pilot pin in an annular cutter?
The pilot pin (also known as an ejector pin) serves three crucial roles during operation:
  • Alignment: It aligns perfectly with your center punch mark to ensure exact hole placement.
  • Coolant delivery: It retracts into the arbor during cutting, opening the path for internal coolant to flow directly to the cutting teeth.
  • Slug ejection: It automatically pushes out the leftover solid metal slug once the hole is fully drilled.
Can I use an annular cutter in a standard drill press or handheld rotary drill?
Annular cutters are engineered for magnetic drills (mag drills) and milling machines. You can use them in a standard drill press only if you use an appropriate mag drill chuck adapter. They should never be used in a standard handheld rotary drill, as they require rigid stability and steady downward pressure to prevent grabbing, shaking, or shattering.
What shank styles do these annular cutters use?
The most common style is the Weldon shank, which features flat sides for set screws to lock the cutter securely into the drill arbor. Many modern cutters also use universal shanks designed to fit both quick-change (tool-less) systems and traditional Weldon arbors. Always ensure your cutter's shank matches your machine's arbor.
What causes an annular cutter to break or chip prematurely?
Premature cutter failure or broken teeth are typically caused by:
  • Insufficient lubrication: Extreme heat buildup weakens the cutting edges.
  • Incorrect feed rates: Feeding too quickly overloads the teeth; feeding too slowly causes work-hardening.
  • Loose magnetic base: If the mag drill shifts or lifts even slightly while drilling, the sideways torque will snap the cutter.
  • Trapped slugs: Forgetting to clear a slug from a previous hole before starting a new one will crush the cutter instantly.
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