براغي رأس أسطوانية HOLO-KROME 60104 3/8-16 × 1-1/2" | محرك سداسي مسطح الرأس | فولاد سبائك معالج بأكسيد أسود حراري (100/عبوة)

Used these on a new jig I was building for a production run, and the flat heads sat perfectly flush in the countersunk holes. The black oxide finish held up well even after a few days of coolant splashing around.

Installed a dozen of these into a steel jig plate this morning and the flat heads seated flush without any issue. The 3/8-16 thread cut cleanly into tapped holes, and the black oxide finish held up fine against the wrench.

Installed a dozen of these in a jig setup and the 3/8-16 threads cut cleanly without any binding. The flat head sits flush perfectly, which is exactly what I needed for precise assemblies. Solid holding power so far.