Cross recessed (+) flat head screw(Full thread Steel Trivalent black(Black) 3 X 5 Pitch 0.5

The head has a flat top surface and a conical bearing surface.
When expressing the nominal length, most other screws indicate the length of the shank only, but for flat head machine screws, the length is measured from the top of the head, which may make them appear shorter than other screws of the same nominal length.

Hot-dip galvanized coating has a large film thickness, so other surface treatments may not be compatible.
Additionally, even with the same hot-dip galvanized finish, compatibility issues may arise if purchased from different suppliers.
In such cases, we may not be able to accept returns, so please acknowledge this in advance before proceeding with your purchase.

Used when you do not want the head to protrude, or when you want it to sit flush with the mating surface.
However, it is necessary to pre-machine a countersink in the mating material to match the conical bearing surface. If this machining is insufficient, the head will protrude. Countersinking is also referred to as "counterboring" in Japanese shop terminology.
Machine Screw Head Dimensions Reference How to Measure Flat Head Screws (Nejikuru Facebook) Flat Head Screw Encyclopedia

• Cross recessed (+) flat head screw Full thread
• Nominal diameter (d) M3
• Length (ℓ) 5.0
• Pitch 0.5
• Cross recess number 2
• Head diameter (dk) Nominal 6 Tolerance 0,-0.5
• Head height (k) Nominal 1.75 Tolerance 0,-0.3
• Head chamfer section (c) Approx. 0.25
• Cross recess (m) Reference 3.6
• Cross recess depth (q) Max 1.43 Min 0.91