Product · Calibration Lab Equipment
Starrett Precision Optical Flat
Precision optical flat — an interferometry-grade glass or quartz reference disc used to verify the flatness of micrometer anvils and gauge faces.
New Refurbished Absolute Certified Surplus
About the Starrett Precision Optical Flat
Optical flats are precision-ground glass or fused-quartz discs, flat to within millionths of an inch, used with a monochromatic light source to reveal interference fringes on a mating surface — the classic method for checking micrometer anvil flatness and parallelism without contact.
A staple of any calibration lab servicing micrometers and other precision hand tools, optical flats require no power and, handled carefully, retain their accuracy indefinitely.
| Specification | Value |
|---|---|
| Material | Optical glass or fused quartz |
| Typical diameters | 1 in to 4 in |
| Flatness | Fractions of a light-band (interferometric grade) |
| Use with | Monochromatic light source |
| Typical use | Micrometer anvil/gauge face flatness checks |
Available across all four PartnerGeometrics condition tiers — New, Refurbished, Absolute Certified, and Surplus. See our condition tier guide for details on what each tier includes.