Multi-angle valve jobs are used to ease the flow transition from the port to the chamber on the intake side and from the chamber to the port on the exhaust side. The width, number and concentricity of these cuts influence sealing effectiveness and flow quality.
Tennys Sandgren is an American professional tennis player competing mainly on the ATP Challenger Tour both in singles and doubles. Born and raised in Gallatin, Tennessee, he went on to play two years of college tennis at the University of Tennessee before launching his professional career.
Then, when he was 22, his left leg overextended during a tennis match. This time he was left with nagging hip pain and an inevitable surgery. Sandgren was flirting with a spot in the top 150 back then and was maybe even a few months away from breaking into the top 100. The injury thwarted his chances then.