HOLO-KROME 72136 5/16-18 × 2" براغي رأس سداسية | محرك رأس سداسي | سبيكة فولاذ معالجة حرارياً باللون الأسود (100 / عبوة)

The black oxide finish on these cap screws looks clean and seems durable, and the hex socket drive made installation a breeze on my milling machine fixture. For the price per pack, this is solid hardware for heavy-duty tooling work.

Used a dozen of these to secure a jig on my milling table, and the black oxide held up perfectly without any galling. The hex socket drive made installation straightforward with a standard allen key.

Installed a batch of these in a production fixture, and the black oxide coating held up nicely against minor abrasion during assembly. The hex socket drive engaged cleanly with no stripping, even at higher torque.