Metal Screw. In fact, screws are known, and screws, screw rods are different from each other. Screw is generally called wood screws; is the tip of the kind of tip, pitch larger, generally used to tighten wood parts, plastic parts. Screw is a screw (mechanical screw), is the kind of front-end flat head, pitch is small, uniform, generally used to fasten the metal, machine parts.
Common specifications
A: Metric screw B: American standard screw C: inch screw
A: Metric mechanical screws: Metric
Ex: M3 x 6 - P P B: M3 mechanical screw, 6mm long, cross, round flat head, black.
Finish Code: The appearance of the specification
Head Code: Head shape
Thread Code
Model: Drive profile: Head profile
Length Code: Screw Length (mm)
A-1: Thread Code: Screw Model
Metric screws directly to the screw diameter of the screw model,
Such as M3 that screw diameter of 3.00mm; M4 that is the outer diameter of 4.00mm screws.
Metric Thread Size x Pitch:
Note: Metric screws on the rear of the screw model, sometimes indicating the screw pitch.
Such as M3x0.5, M4x0.70, M5x0.8, M6x1.
But because the standard specification, usually not mentioned.
A-2: Length Code: Screw Length:
Metric screws, directly marked screw length, in mm.
The total length of the screw mark, only the length of the head below the calculation, excluding the head height.
Except for flat head screws, the total length of the screws is marked with the head height.
A-3: Drive Code / Head profile.
This is a common specification
a. Slotted: word (Minus)
b. Phillips: Cross (Plus)
c. Phil-Slot: word / cross
d. Hex Socket: Hexagon
e. One Way: one-way (only lockable, non-exiting)
A-4: Head Code.
Flat: flat head (after locking, the top flush with the work piece)
b. Oval: salad head, O head, half countersunk head
c. Round: round head
d. Pan: round flat head
e. Truss: big round flat head
f. Hex: Hexagon head.
A-5: Finish Code / appearance processing.
Metric tapping screws: Tapping Type is marked directly after the name.
Ex: M3 x 6 -PPB, Tapping Type:
M3 self-tapping screws, 6mm long, cross, round flat head, black plated.
Generally to the product or mark, and then determine the use of Sheet Metal or plastic parts.
*** The number of teeth per inch. ***
The length of the paragraph
US regulatory screw length to be converted, is the metric mm size.
Conversion formula: (Length Code / 32) x 25.40 = metric length mm
B-3, B-4, B-5: Mark the same way as metric.
Folding Edit this paragraph inch screws
C-1: Thread Code:
The inch is an inch (2.54 cm) within the number of teeth to be fixed, usually 55 degrees. Metric is the distance between the two cords is how much MM to set the pitch, generally 60 degrees
To screw the machine to the ground. Also called anchor bolts.
The difference between the British screw and the American system is difficult to separate with the visualization. The difference between the British and American screws is that the angle of the screw in the inch screw is 55 degrees, and the screw angle of the American screw is 60 degrees. The two standard screws are in most The time is universal, but the 1/2 size of the screw can not, because the British standard 1/2 of the thread is 1 / 2-12 teeth, and the US system is 1 / 2-13 teeth.