APM Hexseal Seelnuts Infographic

One of our earliest innovations is Seelnuts®, which offers reliable performance in temperatures between 103 °F and 400 °F. The self-sealing hardware products are beneficial in a wide variety of applications, easy to install, and compatible with standard bolts, screws, and studs.

APM Hexseal’s Seelnuts are also reusable, meaning that they can be easily removed and reapplied, reestablishing the same reliable seal when torqued.

Our Seelnuts are available in all standard thread sizes as well as a variety of different elastomers to suit your application needs. Seelnuts can also be supplied with self-locking pellets for applications where excessive vibration is an issue.

For information on maximum torque values for Seelnuts® please see our table of Torque Values for Self-Sealing Hardware.

IMPERIAL SEELNUTS® - Standard Nut Style

IMPERIAL SEELNUTS® - Standard Nut Style

Seelnuts
MATERIAL SPECIFICATIONS

For APM Hexseal® Standard Seelnuts®

Nut Material:
Low Carbon Steel with Zinc-Chromate Plating †
Threads:
Imperial— Class 2B ‡; Metric— Class 6H
Elastomer:
Silicone conforms to A-A-59588, Class 3A, GR60, Red ◊
Temperature Range:
-103° F to +400° F ( -75° C to +204° C)
Pressure Range:
Up to 20,000 psig internal and external (subject to clearance hole dimensions).
Resistant to:
Splash, salt spray, sunlight, ozone, weather, fungus, dust, and most acids and lubricating oils.
Shelf Life:
Excess of 25 years.
Thread SizeHeight of Sealing Rib (R)Distance Between Flats (C)Max. Head Height (D)
6-32 UNC-2B1/64"5/16"9/64"
8-32 UNC-2B1/64"3/8"5/32"
10-32 UNF-2B1/64"3/8"5/32"
10-24 UNC-2B1/64"3/8"5/32"
1/4-20 UNC-2B1/64"7/16"7/32"
1/4-28 UNF-2B1/64"7/16"7/32"
5/16-18 UNC-2B1/64"1/2"17/64"
5/16-24 UNF-2B1/64"1/2"17/64"
3/8-16 UNC-2B1/64"9/16"21/64"
3/8-24 UNF-2B1/64"9/16"21/64"
7/16-20 UNF-2B1/32"11/16"3/8"
1/2-13 UNC-2B1/32"3/4"27/64"
1/2-20 UNF-2B1/32"3/4"27/64"
5/8-18 UNF-2B1/32"15/16"35/64"
IMPERIAL SEELNUTS® - Jam Nut Style

IMPERIAL SEELNUTS® - Jam Nut Style

Seelnuts
MATERIAL SPECIFICATIONS

For APM Hexseal® Standard Seelnuts®

Nut Material:
Low Carbon Steel with Zinc-Chromate Plating †
Threads:
Imperial— Class 2B ‡; Metric— Class 6H
Elastomer:
Silicone conforms to A-A-59588, Class 3A, GR60, Red ◊
Temperature Range:
-103° F to +400° F ( -75° C to +204° C)
Pressure Range:
Up to 20,000 psig internal and external (subject to clearance hole dimensions).
Resistant to:
Splash, salt spray, sunlight, ozone, weather, fungus, dust, and most acids and lubricating oils.
Shelf Life:
Excess of 25 years.
Thread SizeHeight of Sealing Rib (R)Distance Between Flats (C)Max. Head Height (D)
6-32 UNC-2B1/64"1/2"7/32"
8-32 UNC-2B1/64"1/2"7/32"
10-32 UNF-2B1/64"1/2"7/32"
10-24 UNC-2B1/64"1/2"7/32"
1/4-20 UNC-2B1/64"5/8"7/32"
1/4-28 UNF-2B1/64"5/8"7/32"
5/16-18 UNC-2B1/64"5/8"7/32"
5/16-24 UNF-2B †1/64"5/8"7/32"
3/8-16 UNC-2B1/64"5/8"7/32"
3/8-24 UNF-2B1/64"5/8"7/32"
1/2-13 UNC-2B1/32"3/4"7/32"
1/2-20 UNF-2B1/32"3/4"7/32"

† The Jam Nut material used for this thread size is Low Carbon Steel with Zinc-Chromate plating.

METRIC* SEELNUTS® - Standard Nut Style

METRIC* SEELNUTS® - Standard Nut Style

Seelnuts
MATERIAL SPECIFICATIONS

For APM Hexseal® Standard Seelnuts®

Nut Material:
Low Carbon Steel with Zinc-Chromate Plating †
Threads:
Imperial— Class 2B ‡; Metric— Class 6H
Elastomer:
Silicone conforms to A-A-59588, Class 3A, GR60, Red ◊
Temperature Range:
-103° F to +400° F ( -75° C to +204° C)
Pressure Range:
Up to 20,000 psig internal and external (subject to clearance hole dimensions).
Resistant to:
Splash, salt spray, sunlight, ozone, weather, fungus, dust, and most acids and lubricating oils.
Shelf Life:
Excess of 25 years.
Thread SizeHeight of Sealing Rib (R)Distance Between Flats (C)Max. Head Height (D)
M3 x 0.50.2mm5.5mm2.2mm
M4 x 0.70.3mm7.0mm3.0mm
M5 x 0.80.4mm8.0mm3.8mm
M6 x 10.5mm10.0mm4.8mm
M8 x 1.250.6mm13.0mm6.3mm
M10 x 1.50.6mm17.0mm7.8mm
M12 x 1.750.8mm19.0mm9.3mm
M14 x 20.1mm22.0mm10.8mm

* APM Hexseal’s standard material for metric nuts is Stainless-Steel.

IMPERIAL SEELNUTS® - Standard Nut Style

IMPERIAL SEELNUTS® - Standard Nut Style

Seelnuts
MATERIAL SPECIFICATIONS

For APM Hexseal® Standard Seelnuts®

Nut Material:
Low Carbon Steel with Zinc-Chromate Plating †
Threads:
Imperial— Class 2B ‡; Metric— Class 6H
Elastomer:
Silicone conforms to A-A-59588, Class 3A, GR60, Red ◊
Temperature Range:
-103° F to +400° F ( -75° C to +204° C)
Pressure Range:
Up to 20,000 psig internal and external (subject to clearance hole dimensions).
Resistant to:
Splash, salt spray, sunlight, ozone, weather, fungus, dust, and most acids and lubricating oils.
Shelf Life:
Excess of 25 years.
Thread SizeHeight of Sealing Rib (R)Distance Between Flats (C)Max. Head Height (D)
6-32 UNC-2B1/64"5/16"9/64"
8-32 UNC-2B1/64"3/8"5/32"
10-32 UNF-2B1/64"3/8"5/32"
10-24 UNC-2B1/64"3/8"5/32"
1/4-20 UNC-2B1/64"7/16"7/32"
1/4-28 UNF-2B1/64"7/16"7/32"
5/16-18 UNC-2B1/64"1/2"17/64"
5/16-24 UNF-2B1/64"1/2"17/64"
3/8-16 UNC-2B1/64"9/16"21/64"
3/8-24 UNF-2B1/64"9/16"21/64"
7/16-20 UNF-2B1/32"11/16"3/8"
1/2-13 UNC-2B1/32"3/4"27/64"
1/2-20 UNF-2B1/32"3/4"27/64"
5/8-18 UNF-2B1/32"15/16"35/64"
IMPERIAL SEELNUTS® - Jam Nut Style

IMPERIAL SEELNUTS® - Jam Nut Style

Seelnuts
MATERIAL SPECIFICATIONS

For APM Hexseal® Standard Seelnuts®

Nut Material:
Low Carbon Steel with Zinc-Chromate Plating †
Threads:
Imperial— Class 2B ‡; Metric— Class 6H
Elastomer:
Silicone conforms to A-A-59588, Class 3A, GR60, Red ◊
Temperature Range:
-103° F to +400° F ( -75° C to +204° C)
Pressure Range:
Up to 20,000 psig internal and external (subject to clearance hole dimensions).
Resistant to:
Splash, salt spray, sunlight, ozone, weather, fungus, dust, and most acids and lubricating oils.
Shelf Life:
Excess of 25 years.
Thread SizeHeight of Sealing Rib (R)Distance Between Flats (C)Max. Head Height (D)
6-32 UNC-2B1/64"1/2"7/32"
8-32 UNC-2B1/64"1/2"7/32"
10-32 UNF-2B1/64"1/2"7/32"
10-24 UNC-2B1/64"1/2"7/32"
1/4-20 UNC-2B1/64"5/8"7/32"
1/4-28 UNF-2B1/64"5/8"7/32"
5/16-18 UNC-2B1/64"5/8"7/32"
5/16-24 UNF-2B †1/64"5/8"7/32"
3/8-16 UNC-2B1/64"5/8"7/32"
3/8-24 UNF-2B1/64"5/8"7/32"
1/2-13 UNC-2B1/32"3/4"7/32"
1/2-20 UNF-2B1/32"3/4"7/32"

† The Jam Nut material used for this thread size is Low Carbon Steel with Zinc-Chromate plating.

METRIC* SEELNUTS® - Standard Nut Style

METRIC* SEELNUTS® - Standard Nut Style

Seelnuts
MATERIAL SPECIFICATIONS

For APM Hexseal® Standard Seelnuts®

Nut Material:
Low Carbon Steel with Zinc-Chromate Plating †
Threads:
Imperial— Class 2B ‡; Metric— Class 6H
Elastomer:
Silicone conforms to A-A-59588, Class 3A, GR60, Red ◊
Temperature Range:
-103° F to +400° F ( -75° C to +204° C)
Pressure Range:
Up to 20,000 psig internal and external (subject to clearance hole dimensions).
Resistant to:
Splash, salt spray, sunlight, ozone, weather, fungus, dust, and most acids and lubricating oils.
Shelf Life:
Excess of 25 years.
Thread SizeHeight of Sealing Rib (R)Distance Between Flats (C)Max. Head Height (D)
M3 x 0.50.2mm5.5mm2.2mm
M4 x 0.70.3mm7.0mm3.0mm
M5 x 0.80.4mm8.0mm3.8mm
M6 x 10.5mm10.0mm4.8mm
M8 x 1.250.6mm13.0mm6.3mm
M10 x 1.50.6mm17.0mm7.8mm
M12 x 1.750.8mm19.0mm9.3mm
M14 x 20.1mm22.0mm10.8mm

* APM Hexseal’s standard material for metric nuts is Stainless-Steel.