Cap Head O-Ring Seal Screws

Cap Head O-Ring Seal Screws are an ideal choice for applications where there is risk of contamination from external matter. They feature a strong, unique, and high quality captive “O” ring which sits in a groove on the underside of the cap head.

This provides 360° of sealant power while maintaining metal to metal contact, which is essential in preventing contaminants from entering the seal or screw. Equally, it stops any leaks from escaping due to its incredibly tight seal. This offers greatly improved performance over a long period of time.

Cap Head O-Ring Seal Screws arrive pre-assembled and ready to use. Available with either a Socket drive, typically to DIN 912 standard / ISO 4762 / ASME B18.3, or a 6 Lobe TX drive, typically to ISO 14579. They are installed using a standard Allen key or 6 Lobe Torx tool respectively.

The O-ring is made of Silicone rubber as standard, but can be supplied in an extensive range of materials – making them suitable for use in almost any environment without deterioration or loss of performance. This includes Nitrile rubber (Buna-N), EPDM, Fluorosilicone, Viton, and many more.

They are often found in valves, electronic devices, panels, food processing equipment, and consumer products – as well as more demanding applications that require high sealing power.

This truly versatile sealing solution is extremely cost effective due to its long lifespan. Optional thread locking patches are also available to provide additional resistance to vibration – further increasing the life of the O-ring.

Cap Head O-Ring Seal Screws are tailor made to meet your requirements – manufactured to order in a wide range of sizes, materials and finishes. Minimum order quantities apply.

We supply a selection of Sealing Fasteners here at Fastenright, including a range of seal screws with various head styles and drive types.

M10 to M30

M1.4 to M8 Technical Data & Availability
Thread Diameter (d)	M1.4	M1.6	M2	M2.5	M3	M3.5	M4	M5	M6	M8
dk max. (mm)	2.6	3	3.8	4.5	5.5	6	7	8.5	10	13
k max. (mm)	1.4	1.6	2	2.5	3	3.5	4	5	6	8
b (mm)	14	15	16	17	18	20	20	22	24	28
Available Lengths (L)	M1.4	M1.6	M2	M2.5	M3	M3.5	M4	M5	M6	M8

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
110mm
120mm
130mm
140mm
150mm
160mm
170mm
180mm
190mm
200mm
210mm
220mm
230mm
240mm
250mm
260mm
270mm
280mm
290mm
300mm

= A2 / 304 Stainless Steel //

= A4 / 316 Stainless Steel
Size not listed? Please make an enquiry – we may be able to provide it.

No.0 to No.12

M10 to M30 Technical Data & Availability
Thread Diameter (d)	M10	M12	M14	M16	M18	M20	M22	M24	M27	M30
dk max. (mm)	16	18	21	24	27	30	33	36	40	45
k max. (mm)	10	12	14	16	18	20	22	24	27	30
b (mm)	32	36	40	44	48	52	56	60	66	72
Available Lengths (L)	M10	M12	M14	M16	M18	M20	M22	M24	M27	M30

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
210mm
220mm
230mm
240mm
250mm
260mm
270mm
280mm
290mm
300mm

= A2 / 304 Stainless Steel //

= A4 / 316 Stainless Steel
Size not listed? Please make an enquiry – we may be able to provide it.

1/4″ to 1″

ASME B18.3 UNC / UNF Technical Data & Availability
Thread Diam. (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	8-36 UNF	10-24 UNC	10-32 UNF	12-24 UNC
dk max (in)	0.096	0.118	0.118	0.140	0.140	0.161	0.161	0.183	0.183	0.205	0.226	0.226	0.270	0.270	0.312	0.312	0.343
k max (in)	0.060	0.073	0.073	0.086	0.086	0.099	0.099	0.112	0.112	0.125	0.138	0.138	0.164	0.164	0.190	0.190	0.216
b max (in)	0.99	0.99	0.99	0.99	0.99	0.99	0.99	0.99	0.99	1	1.05	1.05	1.19	1.19	1.27	1.27	1.27
Avail. 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	8-36 UNF	10-24 UNC	10-32 UNC	12-24 UNC

3/32″

1/8″

5/32″

3/16″

7/32″

1/4″

5/16″

3/8″

7/16″

1/2″

9/16″

5/8″

3/4″

7/8″

1″

1 1/8″

1 1/4″

1 3/8″

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″

5″

6″

8″

= A2 / 304 Stainless Steel //

= A4 / 316 Stainless Steel
Size not listed? Please make an enquiry – we may be able to provide it.

ASME B18.3 UNC / UNF Technical Data & Availability
Thread Diam. (d)	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	7/16-20 UNF	1/2-13 UNC	1/2-20 UNF	5/8-11 UNC	5/8-18 UNC	3/4-10 UNC	3/4-16 UNF	7/8-9 UNC	1″-8 UNC
dk max (in)	0.375	0.375	0.469	0.469	0.562	0.562	0.656	0.656	0.75	0.75	0.938	0.938	1.125	1.125	1.312	1.5
k max (in)	0.25	0.25	0.312	0.312	0.375	0.375	0.438	0.438	0.5	0.5	0.625	0.625	0.75	0.75	0.875	1
b max (in)	1.5	1.5	1.71	1.71	1.94	1.94	2.17	2.17	2.38	2.38	2.82	2.82	3.25	3.25	3.69	1
Avail. Lengths (L)	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	7/16-20 UNF	1/2-13 UNC	1/2-20 UNF	5/8-11 UNC	5/8-18 UNC	3/4-10 UNC	3/4-16 UNF	7/8-9 UNC	1″-8 UNC

1/4″

5/16″

3/8″

7/16″

1/2″

9/16″

5/8″

3/4″

7/8″

1″

1 1/8″

1 1/4″

1 3/8″

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″

11″

12″

= A2 / 304 Stainless Steel //

= A4 / 316 Stainless Steel
Size not listed? Please make an enquiry – we may be able to provide it.

Cap Head O-Ring Seal Screws

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