Countersunk Seal Screws with Under Head Seal

Countersunk Seal Screws with Under Head Seal host a highly durable element that is permanently fused to the bearing surface of the fastener. This material compresses during installation to fill space between the underside of the head and the counter sink.

Designed to prevent the leakage of fluids and gases under pressure, they are often used in place of traditional gaskets. The seal does not shrink or dry out over time for high reusability.

These components offer excellent resistance to a huge range of automotive fluids and chemicals including alcohol, gasoline, kerosene, oil, diesel fuel and hydraulic fluids. They also prevent galvanic corrosion between dissimilar materials.

Countersunk Head Seal Screws with Under Head Seal provide a cost-effective alternative to traditional o-ring seal screws – supplied with a much shorter lead time. Raised Countersunk Under Head Seal Screws are also available at Fastenright.

- Cross Recess Countersunk Under Head Seals Screws are typically in accordance with DIN 965 Type H standard / DIN 965 Type Z standard / ISO 7046-1 / ISO 7046-2 / ASME B18.6.3
- Slotted Countersunk Under Head Seal Screws are typically in accordance with DIN 963 standard / ISO 2009 / ASME B18.6.3
- Socket Countersunk Under Head Seal Screws are typically in accordance with DIN 7991 standard / ISO 10642 / ASME B18.3
- 6 Lobe Torx (TX) Countersunk Under Head Seal Screws are typically in accordance with DIN 965 standard / ISO 14581 / ISO 10642 / ASME B18.6.3

The green seal can be applied to all of our standard materials, including Steel and Stainless Steel, with non-standard materials and finishes available on request. Special seal colours can also be supplied.

Non-standard sizes, materials and finishes are available to order as specials, including small volume manufacture, modifications and bespoke parts made to drawings. Minimum order quantities apply.

We supply an extensive range of Sealing Fasteners here at Fastenright.

M5 to M24

M1 to M4 Technical Data & Availability

Thread
Diameter (d)

M1.2

M1.4

M1.6

M2.5

M3.5

dk max. (mm)

–

3.8

4.78

6.72

–

8.96

k max. (mm)

–

1.24

1.55

1.86

–

2.48

Available
Lengths (L)

M1.2

M1.4

M1.6

M2.5

M3.5

2mm
3mm
4mm
5mm
6mm
8mm
10mm
12mm
14mm
16mm
18mm
20mm
22mm
25mm
30mm
35mm
40mm
45mm
50mm
55mm
60mm
65mm
70mm
75mm
80mm
85mm
90mm
95mm
100mm

= A2 / 304 Stainless Steel //

= A4 / 316 Stainless Steel
Dimensions shown are for ISO 10642 only.
Size not listed? Please make an enquiry – we may be able to provide it.

No.0 to No.10

M5 to M24 Technical Data & Availability

Thread
Diameter (d)

M10

M12

M16

M20

M24

dk max. (mm)

11.2

13.44

17.92

22.4

26.88

33.6

40.32

–

k max. (mm)

3.1

3.72

4.96

6.2

7.44

8.8

10.16

–

Available
Lengths (L)

M10

M12

M16

M20

M24

6mm
8mm
10mm
12mm
14mm
16mm
18mm
20mm
22mm
25mm
30mm
35mm
40mm
45mm
50mm
55mm
60mm
65mm
70mm
75mm
80mm
85mm
90mm
95mm
100mm
110mm
120mm
130mm
140mm
150mm
160mm
170mm
180mm
190mm
200mm

= A2 / 304 Stainless Steel //

= A4 / 316 Stainless Steel
Dimensions shown are for ISO 10642 only.
Size not listed? Please make an enquiry – we may be able to provide it.

No.10 to 7/8″

UNC / UNF Technical Data & Availability

Thread
Diameter
(d)

0-80
UNF

1-64
UNC

1-72
UNF

2-56
UNC

2-64
UNF

3-48
UNC

3-56
UNF

4-40
UNC

4-48
UNF

5-40
UNC

6-32
UNC

6-40
UNF

8-32
UNC

10-24
UNF

dk max.
(in)

0.138

0.168

0.197

–

0.255

0.281

0.307

0.359

0.411

k max.
(in)

0.044

0.054

0.064

–

0.083

0.090

0.097

0.112

0.127

Available
Lengths
(L)

0-80
UNF

1-64
UNC

1-72
UNF

2-56
UNC

2-64
UNF

3-48
UNC

3-56
UNF

4-40
UNC

4-48
UNF

5-40
UNC

6-32
UNC

6-40
UNF

8-32
UNC

10-24
UNF

3/32″

1/8″

5/32″

3/16″

1/4″

5/16″

3/8″

7/16″

1/2″

9/16″

5/8″

3/4″

7/8″

1″

1 1/4″

1 1/2″

1 3/4″

2″

2 1/4″

2 1/2″

2 3/4″

3″

3 1/4″

3 1/2″

3 3/4″

4″

= A2 / 304 Stainless Steel //

= A4 / 316 Stainless Steel
Dimensions shown are for ASME B18.3 only.
Size not listed? Please make an enquiry – we may be able to provide it.

UNC / UNF Technical Data & Availability
Thread Diameter (d)	10-32 UNF	12-24 UNC	1/4-20 UNC	1/4-28 UNF	5/16-18 UNC	5/16-24 UNF	3/8-16 UNC	3/8-24 UNF	7/16-14 UNC	1/2-13 UNC	1/2-20 UNF	5/8-11 UNC	3/4-10 UNC	7/8-9 UNC
dk max. (in)	0.411	–	0.531	0.531	0.656	0.656	0.781	0.781	0.844	0.938	0.938	1.188	1.438	1.688
k max. (in)	0.127	–	0.161	0.161	0.198	0.198	0.234	0.234	0.234	0.251	0.251	0.324	0.396	0.468
Available Lengths (L)	10-32 UNF	12-24 UNC	1/4-20 UNC	1/4-28 UNF	5/16-18 UNC	5/16-24 UNF	3/8-16 UNC	3/8-24 UNF	7/16-14 UNC	1/2-13 UNC	1/2-20 UNF	5/8-11 UNC	3/4-10 UNC	7/8-9 UNC

3/16″

1/4″

5/16″

3/8″

7/16″

1/2″

5/8″

3/4″

7/8″

1″

1 1/4″

1 1/2″

1 3/4″

2″

2 1/4″

2 1/2″

2 3/4″

3″

3 1/4″

3 1/2″

3 3/4″

4″

4 1/2″

5″

5 1/2″

6″

7″

8″

9″

10″

= A2 / 304 Stainless Steel //

= A4 / 316 Stainless Steel
Dimensions shown are for ASME B18.3 only.
Size not listed? Please make an enquiry – we may be able to provide it.

Please make full use of our Fastener rotation by left-clicking and dragging to rotate, and using the mouse wheel to zoom in or out.
For display only, visuals may differ.

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Countersunk Seal Screws with Under Head Seal

Please make full use of our Fastener rotation by left-clicking and dragging to rotate, and using the mouse wheel to zoom in or out. For display only, visuals may differ.

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Please make full use of our Fastener rotation by left-clicking and dragging to rotate, and using the mouse wheel to zoom in or out.
For display only, visuals may differ.