Internal Hex Head Screw

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Internal Hex Head Screw | Custom Nuts and Bolts Manufacturing - Sen Chang

Sen Chang Industrial Co., Ltd., since 1968, is a Internal Hex Head Screw | nuts and bolts manufacturer based in Taiwan.

ISO 9001 certified self tapping screw production processes and stainless steel screws and bolts with meticulous quality control. Screws and bolts including Machine Screws, Tapping Screws, SEMS Screws, Coating Screws and High Tensile Screws.

Sen Chang has been supplying nuts and bolts to customers, both with advanced technology and 48 years of experience, Sen Chang ensures each customer's demands are met.

Internal Hex Head Screw


Process: Using multi blow header to make the head and then threading before passivation. Trivalent chromium zinc plating after heat treating. Coating being the last step
All the items are inspected during the process and before shipping, complying with ISO Working Instruction
Inspection Tools: Calipers, Protrusion-height gage, Micrometer, 2.5D and 2D projector
Measurement Points: Head diameter, Head height, Hex depth, Hex plug gauge, Minor diameter, Thread angle, Pitch, Coat inspection, Nylok inspection
Coating Reports Offered
Nylok Reports Offered


  • Iron
  • Hardness GR8.8
  • Trivalent Chromium Zinc Plated
  • Blue Nylok (90°~180°)


  • Item Specification: M8-1.25*20
  • Item Material: Iron