Flat countersunk (CSK) head screw bolts are Boltead’s main products, we manufacture and supply flat countersunk (CSK) head screw bolts. The following is the basic information of our hexagon socket button head screw bolt products.
Name
DIN7991 CSK Head hex socket bolts
Materials
Carbon Steel/Stainless Steel
Standards
DIN ISO ANC BSW JIS etc.
Strength level
4.8 8.8 10.9 12.9 A2-70 A4-70 A4-80
Size
M3-M50
Surface finish
ZP\HDG\BLACK\Dacromet etc.
Length
15-500
Samples
Available
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Flat Countersunk (CSK) Head Screw Bolts Product Photos
Flat Countersunk (CSK) Head Screw Bolts are Boltead’s products with relatively high production and supply. The following are photos of hexagon socket button head screw bolts using some of the more common surface treatments：
DIN7991 High Strength Grade 4.8 8.8 10.9 12.9 Galvanized White Blue Zinc Plated CSK Flat Head Hex Socket Bolts
DIN7991 High Strength Grade 4.8 8.8 10.9 12.9 Dacromet CSK Flat Head Hex Socket Bolts
DIN7991 High Strength Grade 4.8 8.8 10.9 12.9 Black Oxide CSK Flat Head Hex Socket Bolts
DIN7991 High Strength Grade 4.8 8.8 10.9 12.9 Yellow Zinc Plated CSK Flat Head Hex Socket Bolts
DIN7991 High Strength Grade 4.8 8.8 10.9 12.9 Hot Dip Galvanized HDG CSK Flat Head Hex Socket Bolts
Flat Countersunk (CSK) Head Screw Bolts Product Describsion
Flat countersunk (CSK) head screw boltsare Boltead’s main product. We are a manufacturer of hexagon socket button head screw bolts and also a supplier of hexagon socket button head screw bolts. While producing and supplying hexagon socket button head screw bolts, we also produce nuts, washers and other fastener products used in conjunction with them.
These bolts we produce are generally classified according to whether the material is carbon steel, brass (copper), or stainless steel. More specific classifications are as follows:
DIN7991 High Strength Grade 4.8 8.8 10.9 12.9 Black Oxide CSK Flat Head Hex Socket Bolts
DIN7991 Copper Brass CSK Flat Head Hex Socket Bolts
Carbon steel flat countersunk (CSK) head screw bolts are generally classified according to strength levels. The more common strength levels are: 4.8, 8.8, 10.9, and 12.9. Among them, bolts with grade 8.8 or above are generally called high-strength bolts （high tensile bolts）.Stainless steel Flat countersunk (CSK) head screw bolts are generally classified according to different materials. The more common stainless steel materials are SUS201 SUS304 SUS316
In addition to different materials and strengths, the biggest impact on hexagon socket button head screw bolts is surface treatment. The following are the more common surface treatments for flat countersunk (CSK) head screw bolts: black oxide, black zinc, zinc plated (ZP), color zinc plating (CZP /YZP), hot dip galvanized (HDG), dacromet coating, etc.
Flat Countersunk (CSK) Head Screw Bolts Production Process
These bolts are sent from the raw material line to the final product. They generally go through the following process:
Annealing of raw materials – pickling – drawing – forming – grinding – heat treatment – surface treatment – classification – packaging – shipping
The rough schematic diagram is as follows:
Flat countersunk (CSK) head screw bolts production process
Flat Countersunk (CSK) Head Screw Bolts Application fields
Automotive Industry: These bolts are commonly used in automotive manufacturing for securing various components such as engine covers, transmission housings, brake calipers, and interior trim panels. Their flat head design allows them to sit flush with the surface, providing a clean and streamlined appearance.
Electronics and Electrical Equipment: These bolts find applications in electronics and electrical equipment assembly, where they are used to fasten components such as circuit boards, control panels, enclosures, and terminal blocks. Their low profile head design helps prevent interference with nearby components and reduces the risk of damage to delicate electronic devices.
Furniture Assembly: In furniture manufacturing and assembly, These bolts are utilized for connecting wood or metal components such as table legs, drawer slides, and cabinet doors. Their flat head design allows them to be countersunk into the surface, providing a smooth and flush finish without protrusions.
Construction and Architectural Projects: These bolts are used in construction and architectural projects for securing building materials such as wood, metal, and plastic. They are commonly used for installing fixtures, fittings, and hardware in residential, commercial, and industrial buildings, providing a reliable and aesthetically pleasing fastening solution.
Machinery and Equipment Manufacturing: These bolts find applications in machinery and equipment manufacturing for assembling components such as gearboxes, pumps, conveyor systems, and machine guards. Their flat head design allows for a secure and flush attachment, minimizing the risk of snagging or interference in moving parts.
Marine and Outdoor Applications: These bolts are employed in marine and outdoor environments where corrosion resistance is crucial. They are commonly used for securing boat fittings, outdoor furniture, garden structures, and signage, providing a durable and weather-resistant fastening solution.
Aerospace and Aviation: In aerospace and aviation industries, These bolts are used in aircraft manufacturing and maintenance for securing interior panels, access doors, and equipment mounts. Their low profile head design helps reduce aerodynamic drag and ensures a smooth surface finish.
These bolts are versatile and can be used in many different situations where a secure and durable fastening solution is required.
For more information and knowledge about Flat Countersunk (CSK) Head Screw Bolts, please check our blogs
DIN7991 Head Hex Socket Bolts Standard
Hexagon socket head countersunk head screws DIN 7991
Thread specification
M3
M4
M5
M6
M8
M10
M12
(M14)
M16
(M18)
M20
(M22)
M24
d
P
pitch
0.5
0.7
0.8
1
1.25
1.5
1.75
2
2
2.5
2.5
2.5
3
a
toll.(+2)
90°
90°
90°
90°
90°
90°
90°
90°
90°
90°
90°
60°
60°
b
L≤125
12
14
16
18
twenty two
26
30
34
38
42
46
50
54
125＜L ≤ 200
/
/
/
twenty four
28
32
36
40
44
48
52
56
60
L＞200
/
/
/
/
/
45
49
53
57
61
65
69
73
dk
max = nominal
6
8
10
12
16
20
twenty four
27
30
33
36
36
39
minimum
5.7
7.64
9.64
11.57
15.57
19.48
23.48
26.48
29.48
32.38
35.38
35.38
38.38
ds
max = nominal
3
4
5
6
8
10
12
14
16
18
20
twenty two
twenty four
minimum
2.86
3.82
4.82
5.82
7.78
9.78
11.73
13.73
15.73
17.73
19.67
21.67
23.67
and
minimum
2.3
2.87
3.44
4.58
5.72
6.86
9.15
11.43
11.43
13.72
13.72
16
16
k
maximum value
1.7
2.3
2.8
3.3
4.4
5.5
6.5
7
7.5
8
8.5
13.1
14
s
Nominal
2
2.5
3
4
5
6
8
10
10
12
12
14
14
minimum
2.02
2.52
3.02
4.02
5.02
6.02
8.025
10.025
10.025
12.032
12.032
14.032
14.032
maximum value
2.1
2.6
3.1
4.12
5.14
6.14
8.175
10.175
10.175
12.212
12.212
14.212
14.212
t
max = nominal
1.2
1.8
2.3
2.5
3.5
4.4
4.6
4.8
5.3
5.5
5.9
8.8
10.3
minimum
0.95
1.55
2.05
2.25
3.2
4.1
4.3
4.5
5
5.2
5.6
8.44
9.87
Thousand pieces of steel weight ≈kg
–
–
–
–
–
–
–
–
–
–
–
–
–
thread length b
–
–
–
–
–
–
–
–
–
–
–
–
–
FAQ
How long is your delivery lead time?
Boltead’s delivery cycle is generally 7 to 15 days. If you need more product types and models, or need to customize, the delivery cycle will be longer. In this case, please confirm with our sales professional.
Can you provide samples? How to charge for samples?
Boltead can provide samples for your measurement and testing. The samples are free, and you only need to pay the shipping cost.
Do you support OEM product customization?
Of course. Boltead welcomes OEM/ODM orders. We can not only customize products for you, but also customize your product and its packaging.
What are your payment terms?
For payment amounts <= $1000, 100% prepayment is required. For payment amounts >$1000, 30% prepayment is required, with the balance due before shipment.
Can you provide the relevant documents？
Yes, we can provide most documents, such as material certificates, product testing certificates, certificates of origin, and insurance certificates.
Can you guarantee the safe and reliable delivery of products?
Yes, Boltead can ensure the safe and reliable delivery of products to you. Our product packaging will be reinforced beyond the packaging you choose.
What about the shipping cost?
The shipping cost depends on the delivery method you choose. Express delivery is typically the fastest but also the most expensive option. Sea freight is the best solution for large quantities of goods. We can provide an accurate shipping cost only when we have detailed information about the quantity, weight, and method. Please contact us for more information.
About Boltead Fastener
Boltead is committed to providing the world with the most suitable bolts and nuts!
We manufacture and supply fasteners, striving for excellence in every aspect.
Boltead producing fasteners since 2001.All the fasteners we produce have been supplied for export since 2018.
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Our export countries include Russia, South Korea, Britain, France, Germany, Italy, Canada, Mexico,Brazil, Argentina, Chile, Australia, Indonesia, Thailand, Singapore, Saudi Arabia, Syria, Egypt, Tanzania,Kenya and other countries. Our products will be spread all over the world!
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Boltead – Bolts & Nuts
Add : South of Ximingyang Village, Linmingguan Town, Yongnian District, Handan City, Hebei Province,CHINA
