When you machine type S or type D, please take the following notes into consideration.

1. Type S and type D cannot be disassembled. So machining should be done as an assembly.
2. When machining is carried out for a setting spring-pin hole, tapping hole, key way etc., you must avoid quenched area B shown in the left drawing. Area A is available for machining.
3. When a shaft hole is enlarged, only one size larger hole is possible to machine.
   (However it is not possible to machine a shaft hole, whose size is from S(D)-6 to S(D)-16.)
4. When it is machined, the outer diameter should not be clamped excessively strong.