This is a part called a core pin used in the molding of connectors.
During the molding of connector parts, this pin is inserted into the mold for shaping.
Even such fine pins are designed with materials that withstand repeated use.
The HAP10 used in this product is one of the powder high-speed tool steels, which, unlike regular high-speed steel, is produced through powder sintering, resulting in high hardness and wear resistance.

Approximately 6 millimeters from the tip of this core pin is actually used.
The root's "kakiage" shape remains when the profile grinding wheel is retracted.
Profile grinding is a processing method that performs precise positioning and grinding on a screen projected at about 50 times magnification.
By using a grinding wheel with a small diameter, the R size of the "kakiage" can be minimized, allowing for such precise pin processing through grinding.
The tip is only 0.4 millimeters square, yet it has a stepped precision of ±0.003, showcasing the strengths of profile processing.