T-Bolt T-Head Bolt | Hammer Head Bolt for Marine T-Slot

T-bolt (T-head bolt / hammer head bolt) for marine deck T-slot rail, aluminum profile channel, and shipboard equipment base mounting. Grade 8.8 carbon steel and SS304/SS316 stainless options. DIN 508 and ISO 299 compatible. M6-M36 thread sizes.

What Is a T-Bolt

A T-bolt, also termed T-head bolt or hammer head bolt, features a flat rectangular or hammer-shaped head that inserts into a T-slot channel from the side and rotates 90 degrees to lock. This design eliminates the need for back-side access during assembly. The T-head slides freely along the full length of the slot before final torquing, making it the preferred fastening solution for any application requiring flexible, repositionable equipment mounting on slotted rails, structural channels, and aluminum extrusion profiles.

T-bolts are one-piece fasteners where the shaped head itself functions as both the T-nut and bolt in a single component. This differs from separate T-nut plus bolt assemblies that require two-piece alignment. The integrated hammer head design allows mid-slot insertion anywhere along the channel length, providing faster installation and excellent repositionability compared to conventional bolted connections.

T-Bolt Specification

DIN 508 and ISO 299 Standard Dimensions

T-bolts conform to DIN 508 T-slot nut dimensions and ISO 299 machine tool table T-slot bolt specifications. The T-head width (dimension a) matches standard T-slot groove widths with tolerance of -0.3 to -0.5 mm to ensure secure fit without excessive play.

Standard T-Bolt Sizes (DIN 508):

Custom head dimensions available for non-standard T-slot profiles. Reduced-profile heads for shallow channel clearance and special thread pitches manufactured to drawing specifications.

Material Selection for Marine Environment

Grade 8.8 Carbon Steel with Blue Zinc: Standard choice for interior deck equipment mounting and above-deck installations not directly exposed to seawater. Blue zinc chromate coating provides moderate corrosion resistance (96-200 hours salt spray). Cost-effective for general shipboard T-slot rail fastening.

Grade 8.8 Carbon Steel with PTFE Coated: Enhanced corrosion protection with fluoropolymer topcoat over zinc base. PTFE coating provides chemical resistance and low friction for applications requiring frequent adjustment. Recommended for engine room equipment bases exposed to oil mist and condensate.

Grade 10.9 Carbon Steel with HDG: High-strength option for structural T-slot connections requiring maximum clamp load. Hot-dip galvanized coating provides minimum 500 hours salt spray resistance. Used for heavy equipment foundations and deck cargo securing points.

SS304 Stainless Steel: Good general corrosion resistance for interior applications and intermittent moisture exposure. Suitable for accommodation area equipment mounting and electrical panel T-slot rails. Not recommended for continuous saltwater contact.

SS316 Stainless Steel: Superior chloride resistance for exposed marine deck applications, offshore platform equipment, and coastal installations. SS316 T-bolts provide over 1000 hours salt spray resistance and do not require additional surface treatment. Ships with EN 10204 3.1 mill certificates. The minimum specification for T-slot deck rails on offshore support vessels and research ships.

Marine Application Guide

T-bolts are widely used in ship construction and offshore platforms for adjustable equipment mounting on T-slot deck plating and structural channels.

T-Slot Deck Rail System: Movable equipment foundations are secured to T-slot deck plating using hammer head bolts. The T-head inserts into the deck slot and rotates to lock, allowing continuous adjustment of equipment position before final torquing. Common on offshore support vessels, research vessels, and workboats where equipment layout changes frequently.

Solar Panel Frame Mounting: SS316 T-bolts secure solar power module frames in aluminum extrusion racking systems on ship decks and offshore platforms. The T-head design allows rapid adjustment of panel angle and position during installation. Essential for vessels with solar-assisted power systems.

Adjustable Deck Hardware: Fairleads, deck organizers, and movable cleats are mounted on T-slot channel rails using T-bolts. Crew can reposition deck hardware for different sailing configurations or equipment layouts without drilling new holes. Used on sailing yachts, research vessels, and multi-purpose workboats.

Container Lashing Fittings: T-bolts connect container lashing bridges and twist-lock fittings to deck T-slot rails in container cargo securing arrangements. The adjustable positioning accommodates different container stacking patterns and lashing geometries.

Engine Room Equipment Base: Auxiliary equipment (oil purifiers, fuel heaters, compressors, pumps) mounted on vibration isolation bases use T-bolts in T-slot frameworks. The adjustable mounting allows precise alignment of equipment connections before final clamping. Grade 10.9 HDG T-bolts provide the strength required for rotating machinery.

Aluminum Profile Structures: Ship workshop equipment racks, spare part storage systems, and modular shelving are built from aluminum extrusion profiles connected by T-bolts. The T-slot design allows unlimited reconfiguration as storage needs change.

Installation Method

Insert the T-bolt head into the T-slot from the side at any point along the channel length. Rotate the bolt 90 degrees so the T-head aligns with the slot underside and locks in position. The T-head slides freely along the slot before tightening. Position the equipment bracket or fitting over the bolt shank, place washer and nut, then torque to specification. No back-side wrench access required.

For stainless steel T-bolts, apply anti-seize lubricant to threads before assembly to prevent galling. Use calibrated torque wrenches for structural connections to avoid over-torquing aluminum profiles, which can cause channel lip deformation.

Quality Assurance

SINOFASTENER manufactures T-bolts and hammer head bolt components to DIN 508 and ISO 299 standards, plus full non-standard custom drawings. For vessel T-slot deck systems requiring special head geometry, reduced-profile heads for shallow channel clearance, or titanium grade for weight-critical yacht applications, submit your drawing or channel dimension specification to our engineering team. Annual production capacity 50,000 tons covering M6-M36 in all material grades.

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Email: sales@sinofastener.com
SINOFASTENER - Marine Fastener Supplier