Measuring Guide

Measuring Guide

Bent/Curved Glass Deals With Parts of Circles With or Without Attached Tangents

The distance around the outside of a complete circle is called a circumference. A line drawn completely through the circle is a diameter. Any line extending from the center of a circle to the circumference is the radius. The radius will be the same no matter where in the circle it is measured.
All circles are divided into 360 degrees of arc. Forty-five degrees of arc being equal to an eighth circle, ninety degrees of arc being equal to a quarter circle, etc.

Circular Lite Without Attached Tangent

We need to know the distance around the bend. This is called the Girth or Arc. As all measurements, this can be taken to either the convex or concave face of the glass, but always specifies which. This measurement MUST be taken with a flexible tape. We need to know the radius of the curve you need. The radius is one half of the diameter, if this were to be pictured as a complete circle. If you are unable to obtain an exact measurement of the radius, then give us the chord and the depth measurements.
The Chord is the distance straight across the curve, measuring straight across from point to point. This measurement should be made with a flat ruler. To measure the depth of the curve, take one half of the chord measurement and at that point measure to the top of the curve. With the chord and the depth, we can mathematically determine the radius.
If the glass you need has attached tangents, a tangent being a flat area at the right angle to the radius, we would need additional and slightly different information.
We need the girth. Please note that the term "girth" is the distance around the curve including any flat areas. Measure the chord and the depth as you would for a circular litle. In addition, measure the length of the flat or flats.

Reverse Curve

For reverse curves measure the girth by letting your flexible tape follow along the curves. To obtain the radius, or the chord and depth, treat each of the curves as a separate unit. Measure as you would for a circular curve.


And of course, we must know the height of the glass you need. Please do not use the term “width” in describing bent glass as the term has too many meanings and can lead to confusion.

AutoCAD Drawing Samples

Railing Panel, Bent Non-Sloping
Railing Panel, Bent Sloping up Stairs
Railing Panel, Bent Transitional

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