7/8" - 18 ACME Left hand Trapezoidal 1 Start Tap
ACME thread is a left-hand, 7/8-inch size, 18 threads per inch, 1-start, 2G class high-speed steel thread.
ACME thread is a left-hand, 7/8-inch size, 18 threads per inch, 1-start, 2G class high-speed steel thread.