No, not what is used when a race is too close to call (that’s a photo finish). But a machined finish added to the raised face on a flange to give an extra level of security to prevent leaks and maintain effective seals.
The Phonographic Finish is actually a serrated finish, either concentric or spiral (much like the grooves on a record), that will grip the gasket between pipe sections firmly.
These finishes are typically added on a lathe to specifications set either by the company ordering the flange, the manufacturer or ASME B16.5 guidelines. Below is a render of the completed flange with bolt holes. I would have included a photo of the actual completed unit, but as soon as it was finished, it was rushed to the job site! But that’s why we’re here. Everyone knows who to call when a custom part is needed in a hurry.
Riggs Machine & Fabricating – Serving industry in KY, OH and WV for over 45 years!