There are many types of “screws” (commonly referred to as bolts in standards) in fasteners. The following outlines several of the most commonly used bolts, along with their current latest national standards and core specification ranges:
1. Hexagon socket screw (cup head screw)
This is the most commonly used high-strength screw in mechanical structures.
* GB/T 70.1-2008 (Hexagon socket head cap screws): The current latest version. The specifications are generally M1.6 to M64, and common performance levels include 8.8, 10.9, 12.9, etc.
• GB/T 70.2-2025 (Hexagon socket flat head screws): Published in October 2025, implemented from February 1, 2026, replacing the old version of 2015.
* GB/T 70.3-2008 (Hexagon socket countersunk head screws): the current latest version.
2. Machine screw (slotted/cross-recess screw)
It is commonly used for fastening electronic products, electrical appliances, or thin-walled parts, and is usually screwed into metal/plastic preformed threaded holes without the need for a nut.
* GB/T 67-2016 (slotted pan head screw): specifications approximately M1.6 to M10.
• GB/T 68-2016 (slotted countersunk head screws): specifications approximately M1.6 to M10.
• GB/T 69-2016 (slotted countersunk head screws).
* GB/T 818-2017 (Pan head screws with cross recess).
• GB/T 819.1-2016 (Cross recessed countersunk head screws).
3. Self-tapping screw
Screw directly into the thin steel plate or plastic base hole to tap out the thread by yourself.
• GB/T 845-2017 (Cross recessed pan head tapping screw): specifications ST2.2 to ST9.5.
* GB/T 846-2017 (Cross recessed countersunk head tapping screws): specifications ST2.2 to ST9.5.
• GB/T 5282-2017 (Slotted pan head tapping screws).
• GB/T 3098.5-2025 (Mechanical Properties of Self-tapping Screws): A new standard issued in October 2025, to be implemented in February 2026.
4. Set screw (top screw)
Used to fix the relative position of the shaft and the hub, with one end resting on the shaft.
• GB/T 73-2017 (slotted set screws with flat point).
• GB/T 74-2018 (Slotted set screws with cup point).
* GB/T 75-2018 (Slotted long cylindrical set screws with tightened head).
5. Other common screws
• Wallboard nails/drywall nails: There are often industry standards or enterprise standards, such as JC/T 2384-2016.
• Wood screws: such as GB/T 99-2021 (slotted round head wood screws), etc.
Hint: If it’s for model selection or drawing annotation, prioritize confirming the head style (cylindrical, countersunk, pan head, etc.) and drive method (hexagonal socket, cross recessed, slotted, etc.) of the screw, and then match it with the aforementioned standard number. If you need a specific size parameter table for a certain type, feel free to ask me.