TiAIN Coating Steel Dragon Annular Cutters 12MM 7/8inch Magnetic Drill Bit Set
Industrial Fractional Core Drill Bit | Premium 7/8-Inch Magnetic Drill Cutter for Steel
Problem: Inaccurate Centering and Slow Ejection
When drilling heavy steel on-site, the biggest headaches are tool "walking" (slipping off center) and the metal slug getting stuck inside the cutter. For operators in the USA and Canada, using non-standardized tools often leads to bolt-hole misalignment, which can compromise the structural integrity of a project and waste hours of labor.
Cause: Poor Pilot Engagement and Friction
Standard drills lack a dedicated centering mechanism, causing them to wander under pressure. Furthermore, without a high-precision internal taper, the metal slug expands from heat and seizes against the cutter walls. If the pilot pin doesn't engage perfectly with the spring-loaded arbor, the slug won't eject, forcing the operator to stop and manually pry it out.
Solution: Precision Centering with Automatic Slug Ejection
Our Fractional HSS Annular Cutter is engineered for the American industrial standard. As shown in the image, the cutter works in perfect synergy with a precision Pilot Pin. This pin centers the tool exactly on the mark and triggers a spring-loaded ejection the moment the hole is finished. The 7/8"diameter is precision-ground to ensure a perfect fit for standard heavy-duty bolts used in North American construction.
Technical Parameters
| Feature | Specification |
| Material | Premium HSS-M2 (High-Speed Steel) |
| Diameter (Ø) | 7/8" (0.875 inches) |
| Cutting Depth | 1" (25.4 mm) |
| Shank Style | 3/4" Weldon Shank (Standard Dual Flat) |
| Sizing Standard | Fractional Imperial (North American Standard) |
| Manufacturing | 100% Fully CNC Ground |
| Hardness | HRC 63-65 |
Application: Built for the American Infrastructure
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Steel Building Fabrication: The 7/8" size is the "workhorse" for drilling holes for standard 3/4"and 13/16" structural bolts.
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Bridge & Highway Repair: Ideal for thick-plate drilling where portability and speed are required on-site.
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Oil & Gas Refineries: Heavy-duty performance in alloy steels and structural components.
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Truck & Trailer Repair: Perfect for chassis modification where precision hole diameters are mandatory.
Selection Guide: Professional Tips
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Pilot Pin Synergy: Always use the high-strength pilot pin included/recommended; it centers the cutter and controls internal coolant flow.
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Speed & Feed: For 7/8" HSS cutters, maintain a steady RPM and constant lubrication to prevent "blueing" the cutting edges.
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Laser Marking: Check the laser-etched shank (as seen in the image) to verify size (7/8" * 1") before installation to prevent setup errors.
Professional FAQ (Expert Support)
Q: Why is the 7/8" size so popular in the US market?
A: It is the standard clearance size for 3/4" bolts, providing the exact 1/8" of play required by many American building codes for structural steel connections.
Q: Can I use this cutter with a Nitto One-Touch machine?
A: This specific cutter has a Weldon Shank (two flats). To use it with a One-Touch system, you will need a Weldon-to-One-Touch adapter.
Q: Does the pilot pin come included with the cutter?
A: We offer them both individually and as sets. For the best performance, we recommend purchasing our high-strength pins to match the 1" depth of cut.
Q: How many holes can I expect from one M2 cutter?
A: With proper lubrication and steady pressure on mild steel, you can typically achieve 200–500 holes before needing a professional re-sharpening.
Q: What is the benefit of the fully ground flutes seen in the photo?
A: The smooth, ground surface reduces friction and allows chips to "slide" out effortlessly,
Get in Touch
Have questions about our products or want to discuss a custom order? Our team is ready to help you.