5/16" x 18, National Course Thread, Tap & Drill Set, Carbon Steel, Ideal For Routine Maintenance, Repair Work & For Rethreading Where High Accuracy & Tolerance Thread Is Not Critical, Straight Flutes Are Ground To Provide Rapid Chip Removal For Efficient Threading, Designed For Hand Threading Work In A Variety Of Materials Taps Produce A Class 2B Thread, Includes Letter F Drill Bit.
