Different Types of
Nuts and Bolts
Mumbai · India
What Are Different Types of Nuts and Bolts
A bolt and a nut together do one basic job — clamp two or more parts by converting rotational torque into axial tension along the fastener’s length. But how that clamping happens, how the fastener is driven, how it resists loosening, and how it distributes load against the joined surfaces varies enormously depending on the bolt head design and the nut form paired with it.
Bolt head design determines how torque is applied and how much clearance the joint needs. A hex head bolt is driven externally with a wrench or socket and remains the most common general-purpose design. A socket head (Allen) bolt is driven internally, allowing a smaller head diameter for recessed or space-constrained joints. Carriage bolts have a domed head and a square shank collar that resists rotation once seated, common in wood-to-metal and structural framing. U-bolts and eye bolts aren’t threaded fasteners in the conventional sense at all — they’re shaped for pipe clamping and lifting/rigging respectively.
Nut design, in turn, determines how the joint resists vibration loosening and how much load it distributes. A standard hex nut is the simple baseline. Nylon-insert lock nuts and prevailing-torque lock nuts resist vibration loosening mechanically or through friction. Wing nuts allow hand-tightening without tools. Cap nuts and dome nuts protect exposed threads and improve appearance. Coupling nuts join two threaded rods end-to-end rather than clamping a joint at all.
Akbar Fasteners Pvt. Ltd. exports to over 50 countries, and our full nut and bolt range is manufactured with the same ISO 9001:2015 quality system and full mill test documentation across every material grade we offer.
One Supplier for Every Bolt & Nut Type
Full Bolt & Nut Type Coverage
Hex, socket, carriage, U-bolt, eye bolt, and equivalent nut forms manufactured under one quality system rather than sourced piecemeal.
Every Material Grade We Manufacture
Any bolt or nut type available in stainless, alloy steel, duplex, or nickel alloy — matched to the actual application, not just what’s in stock.
ISO 9001:2015 Batch Consistency
Every batch dimensionally verified with full mill test documentation, regardless of bolt head style or nut form.
Mixed-Order Consolidation
Combine multiple bolt and nut types, sizes, and materials into a single shipment and set of export documents.
Types of Bolts
Hex Head Bolts
The most common bolt design, externally driven with a wrench or socket. Suitable for the majority of structural and mechanical joints.
Socket Head (Allen) Bolts
Internally driven with a hex key, allowing a smaller head diameter for recessed, flush, or tight-clearance applications.
Carriage Bolts
Domed head with a square shank collar that resists rotation once seated — common in wood-to-metal and framing joints.
U-Bolts
U-shaped rod threaded at both ends, used to clamp pipe, tube, or round stock to a mounting surface or bracket.
Eye Bolts
Looped head for attaching cables, hooks, or rigging hardware, used in lifting and load-securing applications.
Stud Bolts
Fully or partially threaded rod without a head, paired with two nuts, standard for flanged piping and pressure vessel joints.
Types of Nuts
Hex Nuts
The standard six-sided nut, paired with hex bolts or stud bolts across the vast majority of mechanical joints.
Nylon-Insert Lock Nuts
A nylon collar grips the bolt thread to resist loosening under vibration, without relying on a locking washer.
Prevailing-Torque (All-Metal) Lock Nuts
A deformed thread section provides friction-based locking, suited to high-temperature joints where nylon isn’t viable.
Wing Nuts
Winged design allows hand-tightening and loosening without tools — common in equipment requiring frequent adjustment.
Cap & Dome Nuts
Enclosed top protects exposed bolt threads from damage and corrosion while improving finished appearance.
Coupling Nuts
Extended-length nut used to join two threaded rods end-to-end rather than clamp a conventional joint.
Hex vs Socket vs Carriage Bolts
Choosing a bolt head design comes down to how much clearance you have, how the bolt will be driven, and whether the joint needs to resist rotation on its own. The comparison below is the one we walk through with buyers before quoting, so the head design matches the actual assembly access and joint requirement.
| Property | Hex Head Bolt | Socket Head Bolt | Carriage Bolt |
|---|---|---|---|
| Drive Type | External — wrench/socket | Internal — hex key | None once seated — self-locking collar |
| Head Clearance Needed | Moderate | Low — compact head | Low — domed, low-profile head |
| Rotation Resistance | None — needs a wrench on both ends | None — needs a wrench on nut side | High — square collar bites into material |
| Best Suited For | General structural & mechanical joints | Recessed, precision, or space-limited joints | Wood-to-metal, framing, one-sided access |
| Typical Torque Capacity | High | High | Moderate |
| Relative Cost | Low | Moderate | Low-Moderate |
Material Grade Range
Stainless Steel 316
The economical corrosion-resistant starting point across all bolt and nut types.
UNS S32750/S32760Super Duplex Steel
High strength and severe chloride resistance for demanding structural and process joints.
UNS N10675Hastelloy B-3
Nickel-molybdenum alloy for severe reducing acid service across stud bolt applications.
UNS R56400Titanium Grade 5
High strength-to-weight fastening across hex, socket, and stud bolt configurations.
Application Areas
Wherever mechanical joints need to be assembled, tightened, or braced.
Structural Steelwork
building and framing joints
Machinery & Equipment
precision equipment assembly
Piping & Flanged Joints
for pressure vessel joints
Automotive & Transport
for vibration-prone assemblies
Construction & Woodworking
wood-to-metal fastening
Pipe & Cable Mounting
conduit clamping
Lifting & Rigging
securing and lifting
General Engineering
every standard assembly need
Standard Export Documentation
Prepared as standard practice regardless of bolt or nut type ordered.
Mill Test Certificate (MTC)
Heat number, chemical composition, and mechanical property verification for every lot.
Certificate of Conformance
Confirms the shipment matches the purchase order specification, type, and grade in full.
Certificate of Origin (COO)
Confirms India as country of manufacture for destination customs purposes.
Commercial Invoice & Packing List
Itemized value, Incoterm, and detailed carton/weight breakdown for customs clearance.
Dimensional Inspection Report
Head style, thread, and diameter verification available on request for critical applications.
Bill of Lading
Ocean or air freight shipping document confirming carrier, mode, and consignee details.
Internationally Recognised Standards Coverage
Related Fastener Grades & Materials
Hastelloy B-3 Stud Bolts
Our established nickel-molybdenum alloy fastening line for severe corrosion service.
View Hastelloy B-3 →Different Types of Inconel Fasteners
Four Inconel grades built for high-temperature and severe corrosion applications.
View Inconel Grades →Different Types of Monel Fasteners
Nickel-copper grades built for seawater and hydrofluoric acid service.
View Monel Grades →DIN 7 Dowel Pins
Precision locating pins for repeatable alignment rather than clamping load.
View Dowel Pins →Not Sure Which
Bolt or Nut Type You Need?
Tell us the joint, the access you have, and the material — and we’ll help you select the right bolt head and nut type. Akbar Fasteners Pvt. Ltd. responds within 24 hours.
Sales: +91 724 0000 733 · Support: +91 800 9315 333 · sales@akbarfasteners.in