A Glass Cutter is a hand tool designed to score the surface of glass by creating a controlled scratch line. This score weakens the glass along a precise path so that, with pressure, the pane can be snapped or broken cleanly along the line. Glass cutters are essential tools in picture framing for cutting glazing (glass) to custom sizes.

Functions of a Glass Cutter

Scoring glass: creates a shallow, consistent groove that directs the break.
Cutting to size: enables framers to prepare glazing that matches specific frame or artwork dimensions.
Custom shaping: allows trimming of stock-sized glass sheets into smaller or non-standard shapes.
Efficiency in framing: provides framers with on-demand control over glazing dimensions without relying on pre-cut glass.

Types of Glass Cutters

Steel Wheel Cutter: traditional style with a small steel wheel that scores the glass.
Tungsten Carbide Wheel Cutter: more durable, producing smoother and longer-lasting scoring lines.
Oil-Fed Glass Cutter: contains a small oil reservoir that lubricates the wheel during scoring, reducing friction and extending tool life.
Pistol-Grip Glass Cutter: ergonomically designed for comfort and control, often used in professional framing or glazing shops.

Best Practices for Using a Glass Cutter

Always score the glass in one continuous motion; do not retrace the line, as it can cause irregular breaks.
Apply consistent pressure-too much can chip the glass, too little won't create a clean break.
Use a straightedge or T-square to guide the cutter for accuracy.
After scoring, snap the glass by hand (with protective gloves) or by using running pliers for precision.
Never attempt to cut tempered glass; it is designed to shatter when stressed.

Considerations in Framing

Glass cutters are typically used on standard picture framing glass, not on specialty products like acrylic, which requires different tools.
Framers often stock full sheets of conservation glass and cut them to custom sizes using this tool.
Safety is critical: protective eyewear and gloves should always be worn when cutting glass.

FAQs

Can I use a glass cutter on acrylic or Plexiglas?: No. Acrylic and Plexiglas require specialized plastic cutters or saws; glass cutters are only for actual glass.
How do I know if I'm applying the right pressure?: You should hear a consistent "tearing" or scratching sound. Excessive noise or chipping indicates too much pressure.
Do I need to lubricate my glass cutter?: If you're using an oil-fed cutter, lubrication is automatic. For others, dipping the wheel lightly in cutting oil can help extend its life and improve scoring smoothness.

Glass Cutter