Hex socket head cap screw(Coarse Steel Unplated 30 X 90(P=3.5 Pitch 3.5

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This is a bolt with a cylindrical head featuring a hexagonal socket.
Tightening is performed using a hex key (Allen wrench). Although classified as a bolt, it is most commonly used without a nut.
It is also known as a cap screw or socket screw.
Spanners and wrenches with jaws for tightening hex bolts require clearance space around the work area, whereas a hex key requires no such space.
For this reason, hex socket head cap screws enable work in confined spaces and allow for more compact machine designs.
Their appearance has also led to increasing use in decorative applications.


Cap Bolts　
Representative Standard Dimensions for CAP Screws　
Hex Socket Head Cap Screws　

• Hex socket head cap screw (Coarse pitch)
• Nominal diameter (d) M30
• Length under head (ℓ) 90.0
• Pitch (P) 3.5
• Thread length (b) Reference 72
• Head diameter (dk) Max(1) Nominal 45.00 Max(2) 45.39 Min 44.61
• Neck diameter (da) Max 33.4
• Body diameter (ds) Max Nominal 30.00 Min 29.67
• Hex socket width across corners (e) Min 25.154
• Head height (k) Max Nominal 30 Min 29.48
• Neck fillet (r) Min 1
• Hex socket width across flats (s) Nominal Nominal 22 Max 22.275 Min 22.065
• Hex socket depth (t) Min 15.5
• Head chamfer (v) Max 3
• ※Max(1) Without knurling: maximum diameter / Max(2) With knurling: maximum diameter