M5 x 8.12mm DIN 7991 Torx Flat Head Countersunk Screw with Blue Nylon Patch

Product Description:

Qimao Metal Manufacturer M5 x 8.12mm DIN 7991 Torx Flat Head Countersunk Screw with Blue Nylon Patch, the thread diameter is M5 with standard coarse pitch of 0.8mm. Overall length 8.12mm as mentioned, but note that for countersunk screws this measurement includes the head. Effective thread length comes out to roughly 6.5mm after you account for head height. Torx drive size is T20 – we’ve found this gives good engagement without being oversized for the diameter. Head diameter runs about 9.2mm, with 90-degree countersink angle per DIN 7991. Material is carbon steel, which is honestly overkill for light duty, but we’ve seen customers really push these things. Surface finish is a thin zinc plating with clear passivation, enough to get through 48-hour salt spray. The blue patch itself is nylon 11, applied to roughly 120 degrees of thread circumference, leaving the rest bare for conductivity if that matters to you.

Specification:

Products Details:

A detail often overlooked with these M5 x 8.12mm DIN 7991 Torx Flat Head Countersunk Screw with Blue Nylon Patch is the head-to-shank fillet radius. DIN 7991 specifies a certain radius there, and we’ve rejected plenty of samples from other suppliers who get this wrong. A sharp corner under the head creates a stress riser, and on a screw this short, you’re working with limited material. We run ours with a generous radius, still within spec but on the higher end of tolerance. Another detail that matters: Torx recess depth. Some manufacturers machine it shallow to save tool life, but then you get bit pop-out during high-speed driving. We hold 1.2mm minimum depth, checked with a go/no-go gauge on every lot. The blue patch goes on after plating – critical because plating chemicals would degrade the nylon if applied before. Also, the patch skips the first and last two threads, making starting easier and putting the lock right at the grip length.

Product Feature:

• M5 x 8.12mm DIN 7991 Torx Flat Head Countersunk Screw with Blue Nylon Patch applied after plating – prevents flaking and keeps locking consistent.

• Torx recess depth at 1.2mm minimum, checked with gauges on every lot. No bit slipping.

• Head-to-shank radius on the generous side of DIN spec. Less stress concentration, less breakage.

• 6g thread tolerance. Snug fit without being hard to start.

• Patch skips first and last threads. Easier starting, full seating guaranteed.

• Thin zinc plating, 48-hour salt spray rated. Nothing heavy, just enough for most indoor and sheltered outdoor work.

Product Application:

• LED display panels – countersunk head sits flush, surface stays flat.

• Motorcycle brake rotors needs M5 x 8.12mm DIN 7991 Torx Flat Head Countersunk Screw with Blue Nylon Patch – vibration resistance from patch, shear strength from 10.9 grade steel.

• Electrical grounding in control cabinets – patch leaves bare metal contact for continuity.

• Automotive interior trim – stops rattles without line-applied adhesives.

• Tight assembly lines – no liquid threadlocker, no curing wait, patch works immediately.

• Thin metal panels – 8.12mm length gives about 6.5mm thread engagement, good for 3-4mm material with standoff.