How to Measure Bent Glass: A Complete Guide to Curved Glass Geometry

At Flickinger Glassworks, we've been crafting custom curved glass in Brooklyn for over 35 years. This guide will walk you through the essential measurements and terminology you need to know when working with bent glass.

When ordering custom curved glass, precise measurements are essential for a perfect fit. Understanding bent glass geometry ensures your project succeeds the first time. Whether this be restoring vintage curio cabinets, designing architectural features, or creating custom lighting.

Home | Curved Glass | How to Measure Bent Glass: A Complete Guide to Curved Glass Geometry

Quick Reference: 4 Essential Measurements

What You Need:

  • Flexible measuring tape
  • String (alternative for girth measurement)
  • Paper and pen to record measurements

The 4 Key Measurements:

  1. Chord/Width – Straight line distance across the bottom of the curve (use measuring tape)
  2. Girth – Distance following the curved surface (use flexible tape or string method)
  3. Depth – Height from the center of the chord to the curve’s peak (use measuring tape)
  4. Height – Overall length of glass piece (perpendicular to chord)

Pro Tip: All measurements should be taken on the outside (convex) surface of the curve!

Understanding Curved Glass Measurements

Every piece of curved glass requires specific measurements to ensure proper fabrication. Here are the key dimensions you’ll need:

Convex Chord

The chord is the straight-line distance between the two endpoints of your curve. Think of it as the “base” of your curve – the shortest distance across the bottom of the arc.

How to measure: Stretch your measuring tape in a straight line between the two endpoints of the curve on the convex (outside) edge of the glass and record the distance.

Convex Girth (Arc Length)

The girth, also called arc length, is the measurement that follows the actual curved face of the glass. This can be measured with a flexible measuring tape or using the string method.

How to measure:

  • Method 1: Use a flexible tape measure and follow the exact contour of the curve from one endpoint to the other on the convex (outside) edge of the glass.
  • Method 2: Use a piece of string to follow the curve on the convex (outside) edge, then straighten the string and measure its length with a measuring tape.

Convex Depth of Curve

The depth is the distance from the center of the chord to the highest point of the curve. This measurement tells us how pronounced your curve is.

How to measure: Using your measuring tape, measure from the chord line straight up to the highest point of the convex (outside) edge of the glass.

Height

This is the overall length of your glass piece, running perpendicular to the chord/width. For most applications, this represents how tall your finished piece will be.

Glass Thickness

Always specify the thickness of glass you need, typically measured in fractions of an inch (1/8″, 3/16″, 1/4″, 3/8″, etc.).

Understanding Curve Terminology

Radius vs. Diameter

  • Radius: The distance from the center point of a circle to its circumference. Or half its diameter.
  • Diameter: A straight line passing through the center of the circle, equal to twice the radius

Degrees of Arc

Curves are often described in degrees. A complete circle equals 360 degrees, so:

  • Quarter circle = 90 degrees
  • Half circle = 180 degrees

Types of Glass Bends We Fabricate

Regular Radius Bend

A simple, consistent curve following a single radius. Most common for curio cabinets, display cases, and architectural features.

J-Bend

A curve that includes both a curved section and a straight section at a 90-degree angle, resembling the letter “J”.

Serpentine or S-Bend

A compound curve that changes direction, creating an S-shaped profile. Often used in decorative applications and modern architecture.

Complex Multi-Curve Designs

For pieces with multiple curves or changing directions, each curve section should be measured separately using the same techniques outlined above.

Pro Tips for Accurate Measurements

Use the Right Tools

  • Measuring tape: Works for all measurements – chord, depth, height/width
  • String: Alternative method for girth measurement (then measure the straightened string)

Specify Your Surface

All measurements should be taken from the outside (convex) surface of the curve for consistency and accuracy in fabrication.

Double-Check Critical Measurements

Take each measurement twice to ensure accuracy. A small error in measurement can result in glass that doesn’t fit properly.

Consider Creating a Template

For complex curves or when precision is critical, creating a physical template ensures the most accurate results:

  • If you have existing glass with an intact curve: Stand the glass on heavy paper or cardboard and carefully trace around it with a fine pen.
  • If you only have the frame (no existing glass): See our template-making process for detailed instructions on creating a template from the frame itself using a rubbing technique.

When Professional Help is Needed

Some curves are too complex for standard measurements.

If your project involves:

  • Multiple compound curves
  • Very tight radii (small curves)
  • Combination straight and curved sections
  • Unusual angles or custom shapes
  • Consider creating a physical template to ensure perfect results.

Bring Your Cabinet Doors to Our Shop

For curio cabinets and furniture restoration, we offer a convenient service where you can bring your cabinet door frames directly to our Brooklyn workshop. We’ll use the actual frame as our template, ensuring a perfect fit every time. We can also handle the installation process, giving you a complete solution from measurement to finished installation.

This eliminates measurement errors entirely and is especially valuable for:

  • Antique cabinets with unique or irregular curves
  • High-value pieces where precision is critical
  • Complex multi-curve designs
  • Cases where original specifications are unknown

Working with Flickinger Glassworks

With over 35 years of experience crafting custom curved glass in Brooklyn, we understand that every project is unique. Our artisans use time-honored techniques combined with modern precision to create curved glass that meets exact specifications.

Ready to get started? Contact us with your measurements or questions:

  • Email: info@flickingerglassworks.com
  • Phone: 718.875.1531
  • Address: 175 Van Dyke St. STE 321A, Brooklyn, NY 11231

Whether you’re working on a historic restoration, custom furniture piece, or architectural installation, our team is here to help bring your vision to life with precision-crafted curved glass.

For step-by-step instructions on creating a physical template for complex curves, see our Template Creation Guide.

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