Hex socket head cap screw(Coarse Steel Unplated 42 X 105(P=4.5

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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): M42
• Length under head (ℓ): 105.0
• Pitch (P): 4.5
• Thread length (b): Reference 96
• Head diameter (dk): Max (1) Nominal 63.00 Max (2) 63.46 Min 62.54
• Neck diameter (da): Max 45.6
• Body diameter (ds): Max Nominal 42.00 Min 41.61
• Hex socket width across corners (e): Min 36.571
• Head height (k): Max Nominal 42 Min 41.38
• Neck fillet (r): Min 1.2
• Hex socket width across flats (s): Nominal Nominal 32 Max 32.33 Min 32.08
• Hex socket depth (t): Min 21
• Head chamfer (v): Max 4.2
• *Max (1) Without knurling maximum diameter / Max (2) With knurling maximum diameter