In addition to fastening, our self-sealing screws and bolts offer a reliable and reusable seal, preventing (or containing!) contamination from dust, air, water, lubricants and other liquid or gaseous substances.

At APM Hexseal, we understand the need for reliable fasteners that can handle extreme conditions where moisture, dust, lubricants, and other factors may compromise the integrity of the hardware or the seal. Our self-sealing screws and self-sealing bolts address these concerns by creating a self-sealing fastener that will hold up to even the harshest environments.

Fasteners often require additional sealing additives, such as messy liquid or paste compounds, to prevent leaks and ensure reliable, secure holds. APM Hexseal’s patented Seelskrews® and Seelbolts® combine dependable fastening hardware with built in weatherproof sealing materials. As a result, our self-sealing screws and bolts offer a reliable and reusable seal, without messy goops that are difficult and tedious to apply. Our sealing fasteners are critical in preventing or containing contamination from dust, air, water, lubricants and other liquid or gaseous substances.

They are also vibration-resistant, making them a great choice for applications that encounter day-to-day jarring, or repetitive movement. Should you need a more serious level of vibration-resistance, our screws and bolts are available with additional locking features, such as self-locking pellets, strips, and patches.

Seelskrews and Seelbolts are available in many standard thread sizes and with various O-ring elastomer options. Some additional customizations include specialty thread-forming variations, tamper-resistant drives, thread captivation, and paint and finish options.

For information on maximum torque values for Seelskrews and Seelbolts, please see our table of Torque Values for Self-Sealing Hardware.

anatomy-of-a-seelskrew

Anatomy of Seelskrews and Seelbolts

The anatomy of our Seelskrews and Seelbolts is simple, yet functional. We started the design with a stainless steel screw with a custom designed undercut head. The stainless steel provides a strong, corrosion-resistant base that’s ideal for fastening. A silicone O-ring is embedded in the groove under the screw’s head, creating a durable seal that resists moisture and corrosive chemicals.

Once fastened into the clearance hole, a Seelskrew or Seelbolt will offer 360° metal-on-metal contact when fully compressed. The Seelskrew or Seelbolt not only holds the component parts in place, but also helps to seal against intrusion from unwanted fluid, gas, and debris. 

Features

APM Hexseal’s Seelskrews and Seelbolts offer a variety of unique features not shared by traditional fastening and sealing hardware, including: 

  • Positive seals while under pressure or vacuum conditions
  • Easy installation
  • Removable and reusable 
  • Compatibility with all surface finishes
  • Broad operating temperature range from -160°F to 500°F (-106°C to 260°C)
  • Full 360° metal-to-metal contact for fastening integrity
  • Uniform high-strength designs
  • UL- and CSA-recognized
  • Made in the USA

Installation

Easy installation is one of the best things about our patented Seelskrews and Seelbolts. Simply screw the hardware into the pre-drilled mounting hole using your standard hand or power tools, the same way you would with a regular bolt or screw. As with standard fasteners, it is important to accurately measure your mounting hole and use the appropriately sized Seelbolt or Seelskrew for your application. When using a tool for installation, be sure to let your APM Hexseal representative know so they can offer advice about the best amount of torque for your material and fastener design. 

Materials

At APM Hexseal, we understand that every project is different. That’s why we offer our products with a wide range of O-ring elastomer materials, coatings, finishes, and locking designs. O-ring materials we offer include silicone, fluorosilicone, Viton, nitrile, neoprene, and EPDM. Our quality stainless steel screws and bolts are passivated and can be painted or coated to meet the particular requirements of nearly any application. Our representatives will discuss the needs of your project in detail and help you customize the ideal fastener design for your needs. 

Applications

APM Hexseal is dedicated to providing customers with functional fixtures and sealing solutions for numerous industries and applications. Though ideal for underwater and outdoor applications with exposure to the elements, our Seelskrews and Seelbolts can be customized for many application types. Industries that benefit from our Seelskrews and Seelbolts include: 

  • Automotive components
  • Aviation and aerospace components
  • Electric, pneumatic, and hydraulic control systems
  • Industrial fasteners for infrastructure
  • Information and communication structures, cellular towers, and solar panels
  • Medical equipment and devices
  • Military ground equipment 
  • Off-road construction equipment 
  • Robotics
  • Sensitive instrumentation
  • Surface marine vehicles and equipment
  • Underwater and nautical equipment

About APM Hexseal

With more than 70 years in the fastening industry, APM Hexseal has the experience necessary to develop innovative and functional fastening and sealing solutions for customers in nearly any industry. We pride ourselves on providing only the highest-quality products, backed by numerous certifications.

To learn more about our superior fastening solutions, Ask the Experts at APM Hexseal today!

Ever Better.


Seelskrews & Seelbolts

IMPERIAL PAN HEAD with CROSS RECESS DRIVE (PHILLIPS)

IMPERIAL PAN HEAD with CROSS RECESS DRIVE (PHILLIPS)

STANDARD PAN HEAD WITH CROSS RECESS DRIVE (PHILLIPS) TYPE CODE R
MATERIAL SPECIFICATIONS

For APM Hexseal® Standard Seelskrews® & Seelbolts®

Screw Material:
18/8 Stainless Steel, passivated
Threads:
Imperial— Class 2A †; Metric— Class 6g
O-Ring Elastomer:
Silicone conforms to A-A-59588, Class 2, GR60 or GR70, Red ‡
Temperature Range:
-80° F to +425° F ( -62° C to +219° 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.
Thread Size Drive Size Min. Length
Available (L)
Max. Head
Diameter (C)
Max. Head
Height (D)
Recommended Clearance
Hole (Min. - Max.)
2-56 UNC-2A #1 1/4" 0.181" 0.062" 0.091" - 0.950"
4-40 UNC-2A #1 1/4" 0.238" 0.080" 0.125" - 0.129"
6-32 UNC-2A #2 1/4" 0.294" 0.097" 0.147" - 0.152"
8-32 UNC-2A #2 1/4" 0.347" 0.115" 0.173" - 0.179"
10-32 UNF-2A #2 3/8" 0.403" 0.133" 0.199" - 0.204"
10-24 UNC-2A #2 3/8" 0.403" 0.133" 0.199" - 0.204"
1/4-20 UNC-2A #3 3/8" 0.517" 0.175" 0.265" - 0.269"
1/4-28 UNF-2A #3 3/8" 0.517" 0.175" 0.265" - 0.269"
METRIC PAN HEAD with CROSS RECESS DRIVE (PHILLIPS)

METRIC PAN HEAD with CROSS RECESS DRIVE (PHILLIPS)

STANDARD PAN HEAD WITH CROSS RECESS DRIVE (PHILLIPS) TYPE CODE R
MATERIAL SPECIFICATIONS

For APM Hexseal® Standard Seelskrews® & Seelbolts®

Screw Material:
18/8 Stainless Steel, passivated
Threads:
Imperial— Class 2A †; Metric— Class 6g
O-Ring Elastomer:
Silicone conforms to A-A-59588, Class 2, GR60 or GR70, Red ‡
Temperature Range:
-80° F to +425° F ( -62° C to +219° 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.
Thread Size Drive Size Min. Length
Available (L)
Max. Head
Diameter (C)
Max. Head
Height (D)
Recommended Clearance
Hole (Min. - Max.)
M2 X 0.40 6g #1 4mm 4.24mm 1.60mm 2.31mm - 2.41mm
M2.5 X 0.45 6g #1 4mm 5.46mm 2.10mm 2.67mm - 2.84mm
M3 X 0.50 6g #2 4mm 6.70mm 2.40mm 3.55mm - 3.65mm
M4 X 0.70 6g #2 4mm 8.69mm 3.05mm 4.39mm - 4.54mm
M5 X 0.80 6g #2 6mm 9.90mm 3.70mm 5.56mm - 5.66mm
M6 X 1 6g #3 6mm 12.58mm 4.60mm 6.73mm - 6.83mm
IMPERIAL PAN HEAD with SLOTTED DRIVE

IMPERIAL PAN HEAD with SLOTTED DRIVE

STANDARD PAN HEAD WITH CROSS RECESS DRIVE (PHILLIPS) TYPE CODE R
MATERIAL SPECIFICATIONS

For APM Hexseal® Standard Seelskrews® & Seelbolts®

Screw Material:
18/8 Stainless Steel, passivated
Threads:
Imperial— Class 2A †; Metric— Class 6g
O-Ring Elastomer:
Silicone conforms to A-A-59588, Class 2, GR60 or GR70, Red ‡
Temperature Range:
-80° F to +425° F ( -62° C to +219° 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.
Thread Size Min. Length
Available (L)
Max. Head
Diameter (C)
Max. Head
Height (D)
Recommended Clearance
Hole (Min. - Max.)
2-56 UNC-2A 1/4" 0.168" 0.055" 0.091" - 0.950"
4-40 UNC-2A 1/4" 0.220" 0.069" 0.125" - 0.129"
6-32 UNC-2A 1/4" 0.271" 0.083" 0.147" - 0.149"
8-32 UNC-2A 1/4" 0.323" 0.097" 0.173" - 0.177"
10-32 UNF-2A 1/4" 0.374" 0.113" 0.199" - 0.201"
10-24 UNC-2A 1/4" 0.374" 0.113" 0.199" - 0.201"
1/4-20 UNC-2A 5/16" 0.493" 0.148" 0.265" - 0.269"
1/4-28 UNF-2A 5/16" 0.493" 0.148" 0.265" - 0.269"
METRIC PAN HEAD with SLOTTED DRIVE

METRIC PAN HEAD with SLOTTED DRIVE

STANDARD PAN HEAD WITH CROSS RECESS DRIVE (PHILLIPS) TYPE CODE R
MATERIAL SPECIFICATIONS

For APM Hexseal® Standard Seelskrews® & Seelbolts®

Screw Material:
18/8 Stainless Steel, passivated
Threads:
Imperial— Class 2A †; Metric— Class 6g
O-Ring Elastomer:
Silicone conforms to A-A-59588, Class 2, GR60 or GR70, Red ‡
Temperature Range:
-80° F to +425° F ( -62° C to +219° 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.
Thread Size Min. Length
Available (L)
Max. Head
Diameter (C)
Max. Head
Height (D)
Recommended Clearance
Hole (Min. - Max.)
M2 x 0.40 6g 4mm 4.24mm 1.37mm 2.31mm - 2.41mm
M2.5 x 0.45 6g 4mm 5.56mm 1.73mm 2.67mm - 2.84mm
M3 x 0.50 6g 4mm 6.22mm 1.90mm 3.55mm - 3.65mm
M4 x 0.70 6g 4mm 8.17mm 2.43mm 4.39mm - 4.54mm
M5 x 0.80 6g 6mm 9.70mm 3.05mm 5.56mm - 5.66mm
M6 x 1 6g 6mm 12.49mm 3.73mm 6.73mm - 6.83mm
M8 x 1.25 6g 6mm 15.62mm 4.52mm 8.45mm - 8.55mm
IMPERIAL FLAT HEAD with CROSS RECESS DRIVE (PHILLIPS)

IMPERIAL FLAT HEAD with CROSS RECESS DRIVE (PHILLIPS)

STANDARD PAN HEAD WITH SLOTTED DRIVE TYPE CODE S
MATERIAL SPECIFICATIONS

For APM Hexseal® Standard Seelskrews® & Seelbolts®

Screw Material:
18/8 Stainless Steel, passivated
Threads:
Imperial— Class 2A †; Metric— Class 6g
O-Ring Elastomer:
Silicone conforms to A-A-59588, Class 2, GR60 or GR70, Red ‡
Temperature Range:
-80° F to +425° F ( -62° C to +219° 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.
Thread SizeDrive SizeMin. Length
Available (L)
Max. Head
Diameter (C)
Recommended Clearance
Hole (Min. - Max.)
2-56 UNC-2A#11/4"0.172"0.091" - 0.950"
4-40 UNC-2A#11/4"0.225"0.125" - 0.129"
6-32 UNC-2A#21/4"0.279"0.147" - 0.152"
8-32 UNC-2A#21/4"0.332"0.173" - 0.179"
10-24 UNC-2A#25/16"0.385"0.199" - 0.204"
10-32 UNF-2A#25/16"0.385"0.199" - 0.204"
1/4-20 UNC-2A#33/8"0.507"0.265" - 0.269"
IMPERIAL HEXAGONAL HEAD BOLT

IMPERIAL HEXAGONAL HEAD BOLT

Hexagonal Head Bolt
MATERIAL SPECIFICATIONS

For APM Hexseal® Standard Seelskrews® & Seelbolts®

Bolt Material:
18/8 Stainless Steel, passivated
Threads:
Imperial— Class 2A †; Metric— Class 6g
O-Ring Elastomer:
Silicone conforms to A-A-59588, Class 2, GR60 or GR70, Red ‡
Temperature Range:
-80° F to +425° F ( -62° C to +219° 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.
Thread SizeMin. Length
Available (L)
Distance Between
Flats (C)
Distance Between
Points (P) †
Max. Head
Height (D)
Recommended Clearance
Hole (Min. - Max.)
1/4-28 UNF-2A3/8"0.440"0.510"0.163"0.265" - 0.269"
1/4-20 UNC-2A3/8"0.440"0.510"0.163"0.265" - 0.269"
5/16-24 UNF-2A1/2"0.502"0.580"0.211"0.332" - 0.336"
5/16-18 UNC-2A3/8"0.502"0.580"0.211"0.332" - 0.336"
3/8-24 UNF-2A5/8"0.565"0.650"0.243"0.395" - 0.399"
3/8-16 UNC-2A1/2"0.565"0.650"0.243"0.395" - 0.399"
1/2-20 UNF-2A1/2"0.752"0.870"0.323"0.530" - 0.534"
1/2-13 UNC-2A3/4"0.752"0.870"0.323"0.530" - 0.534"

† The values provided for Distance Between Points are for reference only.

METRIC HEXAGONAL HEAD BOLT

METRIC HEXAGONAL HEAD BOLT

Hexagonal Head Bolt
MATERIAL SPECIFICATIONS

For APM Hexseal® Standard Seelskrews® & Seelbolts®

Bolt Material:
18/8 Stainless Steel, passivated
Threads:
Imperial— Class 2A †; Metric— Class 6g
O-Ring Elastomer:
Silicone conforms to A-A-59588, Class 2, GR60 or GR70, Red ‡
Temperature Range:
-80° F to +425° F ( -62° C to +219° 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.
Thread SizeMin. Length
Available (L)
Distance Between
Flats (C)
Distance Between
Points (P) †
Max. Head
Height (D)
Recommended Clearance
Hole (Min. - Max.)
M6 X 1 6g8mm10mm11.28mm4.15mm6.73mm - 6.83mm
M8 X 1.25 6g12mm13mm14.69mm5.65mm8.45mm - 8.55mm
M10 X 1.5 6g12mm17mm19.25mm7.18mm10.53mm - 10.64mm
M12 X 1.75 6g20mm19mm21.50mm8.18mm12.79mm - 12.9mm

† The values provided for Distance Between Points are for reference only.

IMPERIAL PAN HEAD with CROSS RECESS DRIVE (PHILLIPS)

IMPERIAL PAN HEAD with CROSS RECESS DRIVE (PHILLIPS)

STANDARD PAN HEAD WITH CROSS RECESS DRIVE (PHILLIPS) TYPE CODE R
MATERIAL SPECIFICATIONS

For APM Hexseal® Standard Seelskrews® & Seelbolts®

Screw Material:
18/8 Stainless Steel, passivated
Threads:
Imperial— Class 2A †; Metric— Class 6g
O-Ring Elastomer:
Silicone conforms to A-A-59588, Class 2, GR60 or GR70, Red ‡
Temperature Range:
-80° F to +425° F ( -62° C to +219° 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.
Thread Size Drive Size Min. Length
Available (L)
Max. Head
Diameter (C)
Max. Head
Height (D)
Recommended Clearance
Hole (Min. - Max.)
2-56 UNC-2A #1 1/4" 0.181" 0.062" 0.091" - 0.950"
4-40 UNC-2A #1 1/4" 0.238" 0.080" 0.125" - 0.129"
6-32 UNC-2A #2 1/4" 0.294" 0.097" 0.147" - 0.152"
8-32 UNC-2A #2 1/4" 0.347" 0.115" 0.173" - 0.179"
10-32 UNF-2A #2 3/8" 0.403" 0.133" 0.199" - 0.204"
10-24 UNC-2A #2 3/8" 0.403" 0.133" 0.199" - 0.204"
1/4-20 UNC-2A #3 3/8" 0.517" 0.175" 0.265" - 0.269"
1/4-28 UNF-2A #3 3/8" 0.517" 0.175" 0.265" - 0.269"
METRIC PAN HEAD with CROSS RECESS DRIVE (PHILLIPS)

METRIC PAN HEAD with CROSS RECESS DRIVE (PHILLIPS)

STANDARD PAN HEAD WITH CROSS RECESS DRIVE (PHILLIPS) TYPE CODE R
MATERIAL SPECIFICATIONS

For APM Hexseal® Standard Seelskrews® & Seelbolts®

Screw Material:
18/8 Stainless Steel, passivated
Threads:
Imperial— Class 2A †; Metric— Class 6g
O-Ring Elastomer:
Silicone conforms to A-A-59588, Class 2, GR60 or GR70, Red ‡
Temperature Range:
-80° F to +425° F ( -62° C to +219° 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.
Thread Size Drive Size Min. Length
Available (L)
Max. Head
Diameter (C)
Max. Head
Height (D)
Recommended Clearance
Hole (Min. - Max.)
M2 X 0.40 6g #1 4mm 4.24mm 1.60mm 2.31mm - 2.41mm
M2.5 X 0.45 6g #1 4mm 5.46mm 2.10mm 2.67mm - 2.84mm
M3 X 0.50 6g #2 4mm 6.70mm 2.40mm 3.55mm - 3.65mm
M4 X 0.70 6g #2 4mm 8.69mm 3.05mm 4.39mm - 4.54mm
M5 X 0.80 6g #2 6mm 9.90mm 3.70mm 5.56mm - 5.66mm
M6 X 1 6g #3 6mm 12.58mm 4.60mm 6.73mm - 6.83mm
IMPERIAL PAN HEAD with SLOTTED DRIVE

IMPERIAL PAN HEAD with SLOTTED DRIVE

STANDARD PAN HEAD WITH CROSS RECESS DRIVE (PHILLIPS) TYPE CODE R
MATERIAL SPECIFICATIONS

For APM Hexseal® Standard Seelskrews® & Seelbolts®

Screw Material:
18/8 Stainless Steel, passivated
Threads:
Imperial— Class 2A †; Metric— Class 6g
O-Ring Elastomer:
Silicone conforms to A-A-59588, Class 2, GR60 or GR70, Red ‡
Temperature Range:
-80° F to +425° F ( -62° C to +219° 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.
Thread Size Min. Length
Available (L)
Max. Head
Diameter (C)
Max. Head
Height (D)
Recommended Clearance
Hole (Min. - Max.)
2-56 UNC-2A 1/4" 0.168" 0.055" 0.091" - 0.950"
4-40 UNC-2A 1/4" 0.220" 0.069" 0.125" - 0.129"
6-32 UNC-2A 1/4" 0.271" 0.083" 0.147" - 0.149"
8-32 UNC-2A 1/4" 0.323" 0.097" 0.173" - 0.177"
10-32 UNF-2A 1/4" 0.374" 0.113" 0.199" - 0.201"
10-24 UNC-2A 1/4" 0.374" 0.113" 0.199" - 0.201"
1/4-20 UNC-2A 5/16" 0.493" 0.148" 0.265" - 0.269"
1/4-28 UNF-2A 5/16" 0.493" 0.148" 0.265" - 0.269"
METRIC PAN HEAD with SLOTTED DRIVE

METRIC PAN HEAD with SLOTTED DRIVE

STANDARD PAN HEAD WITH CROSS RECESS DRIVE (PHILLIPS) TYPE CODE R
MATERIAL SPECIFICATIONS

For APM Hexseal® Standard Seelskrews® & Seelbolts®

Screw Material:
18/8 Stainless Steel, passivated
Threads:
Imperial— Class 2A †; Metric— Class 6g
O-Ring Elastomer:
Silicone conforms to A-A-59588, Class 2, GR60 or GR70, Red ‡
Temperature Range:
-80° F to +425° F ( -62° C to +219° 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.
Thread Size Min. Length
Available (L)
Max. Head
Diameter (C)
Max. Head
Height (D)
Recommended Clearance
Hole (Min. - Max.)
M2 x 0.40 6g 4mm 4.24mm 1.37mm 2.31mm - 2.41mm
M2.5 x 0.45 6g 4mm 5.56mm 1.73mm 2.67mm - 2.84mm
M3 x 0.50 6g 4mm 6.22mm 1.90mm 3.55mm - 3.65mm
M4 x 0.70 6g 4mm 8.17mm 2.43mm 4.39mm - 4.54mm
M5 x 0.80 6g 6mm 9.70mm 3.05mm 5.56mm - 5.66mm
M6 x 1 6g 6mm 12.49mm 3.73mm 6.73mm - 6.83mm
M8 x 1.25 6g 6mm 15.62mm 4.52mm 8.45mm - 8.55mm
IMPERIAL FLAT HEAD with CROSS RECESS DRIVE (PHILLIPS)

IMPERIAL FLAT HEAD with CROSS RECESS DRIVE (PHILLIPS)

STANDARD PAN HEAD WITH SLOTTED DRIVE TYPE CODE S
MATERIAL SPECIFICATIONS

For APM Hexseal® Standard Seelskrews® & Seelbolts®

Screw Material:
18/8 Stainless Steel, passivated
Threads:
Imperial— Class 2A †; Metric— Class 6g
O-Ring Elastomer:
Silicone conforms to A-A-59588, Class 2, GR60 or GR70, Red ‡
Temperature Range:
-80° F to +425° F ( -62° C to +219° 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.
Thread SizeDrive SizeMin. Length
Available (L)
Max. Head
Diameter (C)
Recommended Clearance
Hole (Min. - Max.)
2-56 UNC-2A#11/4"0.172"0.091" - 0.950"
4-40 UNC-2A#11/4"0.225"0.125" - 0.129"
6-32 UNC-2A#21/4"0.279"0.147" - 0.152"
8-32 UNC-2A#21/4"0.332"0.173" - 0.179"
10-24 UNC-2A#25/16"0.385"0.199" - 0.204"
10-32 UNF-2A#25/16"0.385"0.199" - 0.204"
1/4-20 UNC-2A#33/8"0.507"0.265" - 0.269"
IMPERIAL HEXAGONAL HEAD BOLT

IMPERIAL HEXAGONAL HEAD BOLT

Hexagonal Head Bolt
MATERIAL SPECIFICATIONS

For APM Hexseal® Standard Seelskrews® & Seelbolts®

Bolt Material:
18/8 Stainless Steel, passivated
Threads:
Imperial— Class 2A †; Metric— Class 6g
O-Ring Elastomer:
Silicone conforms to A-A-59588, Class 2, GR60 or GR70, Red ‡
Temperature Range:
-80° F to +425° F ( -62° C to +219° 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.
Thread SizeMin. Length
Available (L)
Distance Between
Flats (C)
Distance Between
Points (P) †
Max. Head
Height (D)
Recommended Clearance
Hole (Min. - Max.)
1/4-28 UNF-2A3/8"0.440"0.510"0.163"0.265" - 0.269"
1/4-20 UNC-2A3/8"0.440"0.510"0.163"0.265" - 0.269"
5/16-24 UNF-2A1/2"0.502"0.580"0.211"0.332" - 0.336"
5/16-18 UNC-2A3/8"0.502"0.580"0.211"0.332" - 0.336"
3/8-24 UNF-2A5/8"0.565"0.650"0.243"0.395" - 0.399"
3/8-16 UNC-2A1/2"0.565"0.650"0.243"0.395" - 0.399"
1/2-20 UNF-2A1/2"0.752"0.870"0.323"0.530" - 0.534"
1/2-13 UNC-2A3/4"0.752"0.870"0.323"0.530" - 0.534"

† The values provided for Distance Between Points are for reference only.

METRIC HEXAGONAL HEAD BOLT

METRIC HEXAGONAL HEAD BOLT

Hexagonal Head Bolt
MATERIAL SPECIFICATIONS

For APM Hexseal® Standard Seelskrews® & Seelbolts®

Bolt Material:
18/8 Stainless Steel, passivated
Threads:
Imperial— Class 2A †; Metric— Class 6g
O-Ring Elastomer:
Silicone conforms to A-A-59588, Class 2, GR60 or GR70, Red ‡
Temperature Range:
-80° F to +425° F ( -62° C to +219° 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.
Thread SizeMin. Length
Available (L)
Distance Between
Flats (C)
Distance Between
Points (P) †
Max. Head
Height (D)
Recommended Clearance
Hole (Min. - Max.)
M6 X 1 6g8mm10mm11.28mm4.15mm6.73mm - 6.83mm
M8 X 1.25 6g12mm13mm14.69mm5.65mm8.45mm - 8.55mm
M10 X 1.5 6g12mm17mm19.25mm7.18mm10.53mm - 10.64mm
M12 X 1.75 6g20mm19mm21.50mm8.18mm12.79mm - 12.9mm

† The values provided for Distance Between Points are for reference only.