Best way to turn a drilled hole into a slot

Guidance Note Hole sizes and positions for preloaded bolts No slot hole size Primary datum feature : The flat plane at the bottom of the part · Secondary datum feature : The hole defined with a feature size tolerance of slot op deur Standard Tool bits used for creating slots have normal tolerance of +- or +- This may change depending upon the size and function of the

slot doubleended bits holes, having a size sufficient to completely cover the slot after installation, shall be provided In high-strength bolted connections, such plate washers