TiAIN Coating Steel Dragon Annular Cutters 12MM 7/8inch Magnetic Drill Bit Set

Product Specification

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

Application: Built for the American Infrastructure

• Steel Building Fabrication: The 7/8" size is the "workhorse" for drilling holes for standard 3/4"and 13/16" structural bolts.

• Bridge & Highway Repair: Ideal for thick-plate drilling where portability and speed are required on-site.

• Oil & Gas Refineries: Heavy-duty performance in alloy steels and structural components.

• Truck & Trailer Repair: Perfect for chassis modification where precision hole diameters are mandatory.

Selection Guide: Professional Tips

1. Pilot Pin Synergy: Always use the high-strength pilot pin included/recommended; it centers the cutter and controls internal coolant flow.

2. Speed & Feed: For 7/8" HSS cutters, maintain a steady RPM and constant lubrication to prevent "blueing" the cutting edges.

3. 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,