Precision Machine Tools manufactures large range ring gaskets in accordance with API-6A/ASME 16.20. We manufacture four basic types of ring gaskets; octagonal shape, oval shape, type RX and type BX. These basic shapes are used in pressures up to 20,000 psi. The dimensions are standardized and require specially grooved flanges. The octagonal cross section has a higher sealing efficiency than the oval and would be the preferred gasket. Stock materials include soft iron, low carbon steel, 4-6 chrome (F5), 304, 316,   Inconel and Incoloy.