Sealing Performance
Under High Pressure

APM Hexseal invented and patented pre-assembled
self-sealing fasteners designed to provide both fastening
and sealing integrity in a single unit. Their design features
a resilient O-ring held captive in a precision engineered
groove under the fastener head. This combination of
precise groove geometry and O-ring characteristics
results in an absolute seal regardless of surface finish,
while still providing full metal-to-metal contact.
Vibration-resistant and re-usable, SEELSKREWS®,
SEELBOLTS®, and SEELNUTS® can withstand
internal/external pressures up to 6,000 psi/vacuum at
temperatures from –160°F to +500°F.
Made in the U.S.A., APM Hexseal self-sealing
fasteners are available in standard and metric thread
sizes. And the integral seal can be formulated for compatibility with a wide range of gases and liquids.
They represent a superior sealing alternative to
sealing compounds, tape, chemical coatings, and
deformable washers that attempt to seal the threadform

Custom Self-Sealing
Fasteners
Self-sealing SEELSKREWS®, SEELBOLTS®,
SEELRIVETS® and SEELNUTS® are available in other
sizes, lengths, materials, head styles (including tamperresistant) and finishes. These can be produced with an O-ring material (see Table I) best suited for your application. Also, other types
of fastening hardware like standoffs can be modified to become self-sealing. Should you not find what you need in this catalog, please
consult the factory. We would be pleased to work with you to satisfy your specific application requirements

Features and Benefits
• Positive sealing under pressure or vacuum.
• Easy-to-install … pre-assembled unit installs
like a conventional fastener.
• Metal-to-metal contact resists loosening due to
vibration, and assures fastening integrity.
• Re-usable … repeated installation and
removal does not affect sealing effectiveness.
• Compatible with all surface finishes.
• UL and CSA Recognized … tested and listed
to UL Standard 50, Types 1-13, and CSA
Standard C22.2 No. 40.
• Optional O-ring seal materials assure
performance with wide variety of gases
and liquids.
• Uniformity and high strength assure
repeatable performance.
• No adhesives, coatings or tape required.

Typical Applications
• Pressure Gauges
• Gear Boxes/Transmissions
• Valves
• Motor Housings
• Fuel Tanks
• Cylinders
• Pumps
• Equipment Housings/Cabinets
• Air Conditioning Equipment
• Hydraulic Systems
• Portable Instruments
• Engines
• Instrument Housings/Panels
• Military Equipment
• Portable Communications Equipment
• Food Processing Systems
• Or any application where leakage can
compromise reliability