BullseyeBore Core CG1-100 Drill Guide for Straight Holes - Magnetic

In this review the BullseyeBore Core CG1-100 stands out as a practical solution for anyone who needs consistently perpendicular holes. It is aimed at DIYers, remodelers and tradespeople who want to remove guesswork from drilling; the single biggest reason to buy is its visual alignment system that projects concentric green laser patterns so you can see when the drill is perfectly square to the work surface. The reviewer found the magnetic quick-attach and non-contact operation especially helpful for keeping the worksurface unmarred while maintaining full visibility of the drill bit.

Key Features

• Circular laser pattern: The dual-pattern system projects a fixed Reference Pattern and a variable Alignment Pattern so users can align until the rings are concentric, guaranteeing a square hole.
• High-visibility green laser: The 520nm Class 1, 1mW green lasers increase visibility in bright indoor conditions and indirect sunlight for easier alignment.
• Magnetic quick-attach: The Core connects magnetically to common drill chucks in seconds, allowing fast attachment and removal without tools.
• Works in any orientation: Because it uses projected patterns rather than gravity-dependent levels, it aligns holes on walls, floors, ceilings or angled boards equally well.
• Non-contact operation: The guide never touches the work surface so there are no scratches or marring and the operator keeps a clear view of the bit and hole location.
• Safety-engineered breakaway: If the unit contacts an object the magnetic connection breaks to stop rotation of the guide while the bit continues, reducing risk to the tool and workpiece.

Who It's For

The Core is best for homeowners, woodworkers and tradespeople who regularly need straight holes and want a simple, visual method to check squareness without complex setups or jigs. It is ideal where visibility matters, such as finished surfaces or bright interiors, and for users who switch quickly between guided and unguided drilling.

Those who should look elsewhere include users of rotary hammer drills (the Core is not compatible) and anyone who needs an integrated mechanical guide that physically contacts the workpiece rather than a non-contact visual alignment tool.

Pros & Cons

Pros

• Precise visual alignment removes the guesswork and makes consistently perpendicular holes easier to achieve.
• Strong magnetic attachment and sturdy build make it feel durable and reliable in everyday use.
• Non-contact design preserves delicate or finished surfaces while keeping the drill bit fully visible.
• Works at any angle, so operators can drill on walls, ceilings and floors without relying on gravity-based leveling.

Cons

• Some users may find alignment requires practice to interpret the concentric patterns quickly and consistently.
• Not compatible with rotary hammer drills, so it is limited to common commercial drills only.

Specifications

Model	CG1-100
Laser	Green 520nm, Class 1, 1mW
Supported bit size	2 in to 5 in
Attachment	Magnetic quick-attach to drill chuck face
Operation	Non-contact visual alignment; works in any orientation
Compatibility	Common commercial drills (not rotary hammer drills)

Our Verdict

The BullseyeBore Core CG1-100 is a smart, practical accessory for anyone who needs to drill straight holes without bulky jigs. Its clear dual green laser patterns, magnetic quick-attach and non-contact operation make it good value for woodworkers and DIYers who value surface protection and visibility. While it takes a little practice to read the patterns quickly, it reliably removes guesswork and speeds up accurate drilling across a range of orientations.

Frequently Asked Questions

Will this attach to my drill?
It attaches magnetically to the face of thousands of common commercial drills; it is not compatible with rotary hammer drills.

How does the alignment work?
The Core projects a fixed Reference Pattern and a variable Alignment Pattern; when the rings are concentric the drill is perpendicular to the worksurface.

Will it mark or scratch finished surfaces?
No, the device operates without touching the workpiece so it avoids scratches and preserves finished surfaces.