While doing operation 01,dia 9.8 carbide drill running in program O0103(28_044_0103_10REA_R00) .Due to un even  Surface in the casting material ,the drill did not passed perpendicualr to face and also reamed hole.Because of this problem locating hole pitch was not achived as per process which in turn the part was not butted in the next operation.the part was lightly liffted while doing 03 operation which took extra cut on the material while finishing the thickness