(-)Flat head machine screw(Coarse Brass Unplated 8 X 50 Pitch 1.25

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) M8
• Length under head (ℓ) 50.0
• Pitch (P) 1.25
• Head diameter (dk) Nominal 14.0 Tolerance 0,-0.8
• Head height (k) Nominal 5.2 Tolerance ±0.2
• Slot width (n) Reference 1.6
• Slot depth (t) Reference 2.8