By projecting a magnified shadow or image of your part onto a screen, these optical comparators give you an easy way to measure and inspect its precise features. They work similarly to overhead projectors, but with fixed magnification to preserve proportions. Because of how easy they are to set up and use, they’re a staple in most machine shops. They shine light from above, so they’re best for inspecting flat parts, such as gaskets and O-rings. Unlike traditional optical comparators, these comparators are compact to fit easily on a benchtop.

To use these comparators, choose profile or surface lighting. Profile lighting creates a shadow of your part, which you can use to plot points for precise measurements. To plot each point, move the stage the part rests on until the point lines up with the crosshair on the projector screen. For precision, the stage moves in increments thinner than a sheet of paper. Surface lighting makes these comparators work like an illuminated magnifier, blanketing the part with even light to reveal scratches, dents, and other surface flaws.

Save the measurements you’ve gathered for later by exporting the data as a text file using an RS-232 cord (not included).

Optical comparators with edge detection increase accuracy and efficiency by reducing human error. No need to identify each edge yourself with the crosshair—these comparators register whether they are passing over your object's shadow or a gap, such as a hole or cutout. The graphic display screen shows a visual representation of the part you’re measuring, making it easy to identify and measure specific features. To make sure each part is inspected the same way, create a program that guides anyone using the comparator on what steps to follow.

Holders, swivel center supports, and V-blocks securely hold your part as you measure. V-blocks hold round parts.

If you need to inspect your part from different angles, use either a swivel center support or a rotary table. Swivel center supports turn around a horizontal axis, moving your part in a circle like a Ferris wheel. Rotary tables spin around a vertical axis, rotating your part just like a carousel.

Scales and charts are clear, so you can lay them on top of your comparator’s projector screen. Scales give you a way to check your comparator’s magnification and length measurements. Charts are for checking angle measurements.

Filters are blue to increase contrast and reduce glare on your comparator’s projector screen.