Black Oxide Shoulder Screw with Red Nylon Patch for Precision Locating

Short Description:

This carbon steel shoulder screw features a precision machined shoulder for accurate positioning. Black oxide finish keeps dimensions stable, and the pre-applied red nylon patch delivers reliable anti-loosening performance under vibration.

Product Detail

Product Tags

This shoulder screw is one of our regular custom fasteners for factory assembly work. You can see a smooth shoulder section sitting between the head and threads. When assembling, this shoulder takes care of positioning, and the thread only does the clamping work. This is the big difference compared with a normal machine screw.

We run black oxide treatment over the whole body. A red nylon patch is pre‑coated on the threaded area. Once locked in place, this nylon patch creates friction, so the screw won’t back off easily under continuous vibration.

01 About the Shoulder Locating Section

The shoulder cylinder is the core of this part. We control its diameter strictly during CNC turning. If tolerance drifts too much, the screw will either get stuck in the hole or sit loose. Lots of buyers overlook this point at the beginning and run into assembly trouble later.

It also works as a stop. It limits how deep the screw can go, so you won’t over‑tighten and crush your workpiece surface. That’s a huge plus for delicate jigs and electronic modules.

Black Oxide Surface Treatment Notes

Black oxide is not plating. It’s a thin chemical film formed directly on carbon steel. Hardly any extra thickness adds to the part after treatment. That’s exactly why we pick it for these tight‑tolerance shoulder screws.

The surface comes out matte black. When the shoulder slides against other metal parts, it rarely flakes or sheds debris. Still, its rust resistance is basic, fit for dry indoor use only.

Red Nylon Patch Lock Feature

The red nylon patch is applied under stable temperature in our shop. When you turn the screw into mating threads, the nylon material gets squeezed. The interference stops spontaneous loosening caused by shaking or repeated rotation.

It’s not permanent lock. You can still take the screw apart with standard tools when needed. Most clients use this locking style for moving hinge structures and adjustable test fixtures.

Common Application Scenarios

We ship this style to buyers building automation fixtures all the time. It also fits inspection tooling, small equipment hinges, internal brackets for electronics, tiny robot linkages.

Custom Options We Offer

We can adjust nearly every dimension following your drawing. Shoulder diameter, shoulder length, thread size, head thickness, nylon patch position are all changeable. If black oxide is not suitable, we can switch to zinc plating, Geomet or Dacromet.

Our In‑house Quality Check

Every batch gets checked before packing out. Workers verify shoulder dimension and thread profile with gauges. We also pull sample units to run torque tests for the nylon patch. All processes are done inside our own factory to catch issues early.