STARCO Wheel Manufacturing | Page 13

PLAIN SEAT SPHERICAL COUNTERSINK CONICAL COUNTERSINK ``The bore of the wheel fits very closely to the hub spigot and the wheel centers itself ``The countersink stud hole design centers the wheel and keeps it in position. ``British Standard / Imperial Standard. ``The spherical countersink is expressed as a radius, e.g. R16 (radius of 16 mm). ``The shape of the countersink is expressed in degrees, the most popular being 90°, 80°and 60°. E.g. with C90 (90°) ``The conical countersink is expressed as an angle e.g. 60°. Plain seat Spherical countersink Conical countersink PLAIN SEAT ``This method produces the strongest seat, as no material is removed. Being pressed rather than machined, indeed the compression of the metal makes it harder and stronger. Countersink can be conical or spherical. Puching and forming...step 1 Step 2 Step 3 starco.com 13