How to Measure for Desktop Glass
Protective glass tops for desks, tables, credenzas, and other flat-surface furniture is an attractive and easy way to protect your household investments. This article will provide guidance about how to take measurements for your flat-top furniture surface. (If you're looking for an actual glass TOP for a table base, where the glass is the actual surface itself, rather than simply covering a surface, contact us for help.)
BEFORE YOU BEGIN
Test for a flat surface: Place a ruler or yardstick on edge on the surface -- it should touch evenly along its entire length. Move the stick around to check the entire surface. If you find uneven spots, note their approximate depth, size, and location on the surface, and contact us for help. Do not order glass for an uneven surface without consulting us first! Our aim is to provide a quality product that will last, and the more information you provide, the easier it is for us to help you.
Type of glass: Most desktop glass is 1/4" thick. Clear, Bronze, and Grey (either light grey tint or darker "Greylite 14") are the most common types of glass for this application. If you're looking for something other than these, contact us to discuss options.
Edgework: For a review of different glass edge treatments, see our edgework article.
SIMPLE RECTANGLE: Straight sides, 90-degree corners
Most desks and credenzas, as well as many tables, are rectangles with straight sides and 90-degree corners. In this case, width & length, each measured to the nearest 1/16 of an inch, are typically all that is needed. HOWEVER, it is a good idea to check for squareness, to assure that the corners are true 90-degrees. The easiest way to do this is to measure diagonally from corner to corner, then again in the other diagonal direction. The two measurements should be equal. If they are not, the surface may not be square. In this case, see making a paper pattern.
RECTANGLE W/ RADIUS CORNERS: Straight sides, rounded or angled corners
If the overall pattern is a straight-sided rectangle, but the corners are angled or rounded, you can often simply provide overall dimensions (as in "SIMPLE RECTANGLE" above), plus a paper pattern of the corners. Unless you are absolutely certain the four corners are identical, make a pattern of each one, and note the locations of each pattern on the overall piece. To make a paper pattern, see making a paper pattern.
TRAPEZOID OR OTHER STRAIGHT-SIDED SHAPE
In most cases, it's safest to make a paper pattern of any non-rectangular surface (see MAKING A PAPER PATTERN). However, careful and thorough measurements of a trapezoid or other straight-sided shape may be sufficient. The sketches below show the dimensions that must be provided to assure an accurate glass piece.
With a right-angle trapezoid, the length of all four sides should be enough. Use a T-square to assure that the right angles are a true 90-degrees:
With a trapezoid lacking right angles, we will need not only the four side dimensions, but also the height of the shape from parallel side to parallel side (#5 in the sketch below):
With a parallelogram, you must measure not only the four sides and the height, but also the slope offset (#2 and #5 in the sketch at left). This can be very tricky to measure accurately, and it is strongly recommended that a paper pattern be made in this cases.