(-)Flat head machine screw(Coarse Stainless steel Unplated 1.4 X 2.5

The head of a round machine screw is nearly hemispherical in shape, similar to today's truss head machine screw. The flat head machine screw has a low-profile cylindrical head. It was commonly manufactured in the past due to its simple production method.
Machine Screw Head Dimensions List　Encyclopedia of Round & Flat Head Machine Screws

• Slotted (-) flat head machine screw, coarse pitch
• Nominal thread diameter (d): M1.4
• Length under head (ℓ): 2.5
• Pitch (P): 0.3
• Head diameter (dk): Nominal 2.6, Tolerance 0,-0.4
• Head height (k): Nominal 0.9, Tolerance ±0.1
• Slot width (n): Reference 0.32
• Slot depth (t): Reference 0.5
• ※M1.4 is available in stainless steel only.