HOLO-KROME 42058 1/2-13 X 1" 滾花錐端內六角固定螺絲 | 合金鋼熱處理黑色氧化 (50 / 包)

The knurled cups on these set screws really bite into the shaft once tightened, making them perfect for locking pulleys in place. I used them on a mower deck and haven't had a single wobble since.

The box showed up with all 50 screws accounted for, and the black oxide finish looks even better in person than in the photos. The hex socket drive seated cleanly on my Allen key with zero wobble, so clamping the set screws into tapped holes was quick work.

The knurled cup point grips the shaft way better than the plain set screws I've used before—no slipping even under vibration. The black oxide finish looks clean and the threads seated smoothly into the tapped hole. Exactly what I needed for a stubborn clamping job.