Ratchet Compass Cutter 189B / OLFA

• Model: 189B
• Cutting Diameter: 1.6–22 cm (4–22 cm with hole-prevention plate)
• Cutting Direction: Clockwise only; counterclockwise rotates handle only
• Compatible Materials: Paper, vinyl, film
• Included: 10 replacement blades, hole-prevention plate
• Packaging: Blister pack
• Arm Material: ABS resin (30% glass fiber)
• Shaft Material: ABS resin
• Handle / Gear Material: Polyacetal resin
• Blade Material: Alloy tool steel

Cutting a clean circle by hand is one of those tasks that sounds simple but tends to go wrong. A standard compass cutter requires you to rotate your wrist continuously through a full arc, which puts strain on the joint and often causes the blade to drift or the center needle to slip.

OLFA's answer is the ratchet mechanism built into the 189B's handle. Turning clockwise advances the cut; turning counterclockwise lets the handle spin freely without moving the blade body. The result is a short, controlled stroke repeated around the arc rather than one long wrist rotation. The included hole-prevention plate sits under the center point to keep the needle from piercing through the material, and the blade itself is replaceable using a single screw. The included blades are scored so they can be snapped to the correct length with pliers before first use.