Hammer Head Screws Manufacturer in India | Stainless Hammer Head Bolts

Overview

Stainless Hammer Head Bolts & T-Head Bolts: Manufacturer & Distributor

A hammer head bolt has a long, narrow head shaped like the head of a hammer. It drops into a slot or channel, turns under the edges and holds there, so parts can be fixed anywhere along the slot without drilling.

Exotic Alloy manufactures hammer head bolts in Mumbai, India, for building services, façade and solar installers, machine builders and steel fabricators. We stock across India and supply Spain, Europe, the Gulf and Africa. Small heads are cold formed, large T-heads are hot forged, and threads are rolled.

Two families

DIN T-head bolts (DIN 261, 186, 188) slide into machine-table T-slots and foundation slots. Channel hammer head bolts, like the ones in our photo, are inserted through the slot of an anchor or mounting channel and turned 90°; a notch in the thread end shows which way the head points. For the matching nuts and washers see nuts and washers.

DIN 261 DIN 186 square neck DIN 188 double nib Channel bolts A2 / A4 & HDG

Hammer head bolt at a glance

Head: Rectangular, width = thread size (DIN)
Fixing: Turned 90° under channel lips, or slid into a T-slot
Anti-turn: Square neck (DIN 186) or nibs (DIN 188)
Marking: Notch in the thread end shows head direction
Grades: A2-70, A4-50, A4-70; 4.6, 8.8
Related: T head screws, square head bolts, anchor fasteners

How a channel hammer head bolt locks (schematic). Insert the head along the slot, turn it 90° clockwise and check that the notch lies across the channel; the section shows the head bearing under both lips. Proportions follow an M12 DIN 261 head; the channel is generic.

Specification

Hammer Head Bolt Specification

The range we manufacture and supply.

StandardsDIN 261 (T-head); DIN 186 (square neck); DIN 188 (double nib); channel bolts to drawing

Size rangeDIN 261 M8–M100 × 6; DIN 186 M6–M48; DIN 188 M8–M80 × 6; channel bolts M8–M20

ThreadMetric coarse 6g; M72 and above fine pitch 6 mm

LengthsTo order; fully or partly threaded

Grades4.6, 8.8 (ISO 898-1); A2-70, A4-50, A4-70 (ISO 3506-1)

FinishPlain or passivated stainless; zinc plated or hot-dip galvanised steel

Head markingNotch in the thread end along the head (channel bolts)

Supplied withHex nuts and washers on request, as sets

CertificationMill certificate; EN 10204 3.1; PMI for stainless

PackingBoxes, bags and site kits labelled by size

Types

DIN 261 vs DIN 186 vs DIN 188 Hammer Head Bolts

Same head, three ways to stop the bolt turning while the nut is tightened.

The three DIN types at M12. Heads to scale from the DIN tables; the square neck and nibs are drawn schematically.

Type	Under the head	Sizes	Typical use
DIN 261	Plain	M8–M100 × 6	T-slots whose walls stop the head turning
DIN 186	Square neck	M6–M48	T-slots, foundations, square holes
DIN 188	Two nibs	M8–M80 × 6	Foundations and frames where the nibs lock the head
Channel bolt	Plain head, notched end	M8–M20	Anchor channels, mounting rails, solar structures

Dimensions

Hammer Head Bolt Dimensions

DIN 261 heads from M8 to M36 at the same scale, top view with the thread circle and side view; outlines simplified.

Thread	Pitch P	m head length nom	n head width nom	k head height nom	A_s stress area mm²
M8	1.25	18	8	5.5	36.6
M10	1.5	21	10	7	58
M12	1.75	26	12	8	84.3
M16	2	30	16	10.5	157
M20	2.5	36	20	13	245
M24	3	43	24	15	353
M30	3.5	54	30	19	561
M36	4	66	36	23	817
M42	4.5	80	42	26	1121
M48	5	88	48	30	1473
M56	5.5	102	56	35	2030
M64	6	115	64	40	2676
M72 × 6	6	128	72	45	–
M80 × 6	6	140	80	50	–
M90 × 6	6	155	90	55	–
M100 × 6	6	170	100	62	–

DIN 261:2010 T-head bolts, mm. Stress area A_s from ISO 898-1, up to M64.

Thread	Pitch P	m head length nom	n head width nom	k head height nom
M6	1	16	6	4.5
M8	1.25	18	8	5.5
M10	1.5	21	10	7
M12	1.75	26	12	8
M16	2	30	16	10.5
M20	2.5	36	20	13
M24	3	43	24	15
M30	3.5	54	30	19
M36	4	66	36	23
M42	4.5	80	42	26
M48	5	88	48	30

DIN 186:2010 T-head bolts with square neck, mm. Neck dimensions to the standard; ask for a drawing.

Thread	m head length nom	n head width nom	k head height nom
M8	18	8	5.5
M10	21	10	7
M12	26	12	8
M16	30	16	10.5
M20	36	20	13
M24	43	24	15
M30	54	30	19
M36	66	36	23
M42	80	42	26
M48	88	48	30
M56	102	56	35
M64	115	64	40
M72 × 6	128	72	45
M80 × 6	140	80	50

DIN 188:2011 T-head bolts with double nib, mm.

Channel profile width / depth, mm	Typical bolt threads	Common classes
28/15	M8, M10, M12	4.6, 8.8, A4-50, A4-70
38/17	M10, M12, M16	4.6, 8.8, A4-50, A4-70
40/22	M10, M12, M16	4.6, 8.8, A4-50, A4-70
50/30	M12, M16, M20	4.6, 8.8, A4-50, A4-70

Typical bolt sizes for common channel profiles. Head length and shape differ between channel makers: send us your channel drawing or part number and we match it.

Installation

Installing Hammer Head Bolts

1. Insert

Push the head into the channel slot lengthways, at any point along the channel.

2. Turn 90°

Turn clockwise until the head stops under both lips.

3. Check the notch

The notch in the thread end must lie across the channel.

4. Fixture & washer

Place the part and a washer of the same material as the bolt.

5. Tighten

Tighten the nut to the torque given by the channel maker.

T-slots

DIN T-head bolts slide in from the end of the slot; check the head fits the slot width and depth.

Strength

Hammer Head Bolt Property Classes & Loads

The bolt is only one part of the joint: in a channel or T-slot, the lips or slot usually give way first.

Class	Standard	R_m min MPa	R_p0.2 / R_e min MPa	M12 breaking load min, kN	M16 breaking load min, kN
4.6	ISO 898-1	400	240	33.7	62.8
8.8	ISO 898-1	800	640	67.4	125.6
A4-50	ISO 3506-1	500	210	42.1	78.5
A2-70 / A4-70	ISO 3506-1	700	450	59.0	109.9
A4-80	ISO 3506-1	800	600	67.4	125.6

Minimum breaking load = stress area × minimum tensile strength (our calculation from ISO 898-1 and ISO 3506-1). These are bolt values, not working loads: use the channel maker’s design loads for the fixing.

Calculator

Hammer Head Bolt Size & Load Calculator

Pick a size and class to see the head dimensions, the typical channels and the bolt’s own minimum loads.

Bolt

Thread

Property class

Head sizes from DIN 261 (DIN 186 for M6). Loads are our calculation: stress area × minimum tensile strength or yield strength (ISO 898-1, ISO 3506-1). Bolt values only, not safe working loads.

Result

67.4

kN min breaking load

54.0

kN min yield load

Head (m × n × k):26 × 12 × 8 mm

Stress area:84.3 mm²

Typical channels:28/15, 38/17, 40/22, 50/30

Materials

Hammer Head Bolt Materials & Finishes

Material	Classes	Finish	Best for
Carbon steel	4.6, 8.8	Zinc plated	Dry indoor services and machines
Carbon steel	4.6, 8.8	Hot-dip galvanised	Outdoor steelwork, solar structures
A2 stainless (304)	A2-70	Plain, passivated	Indoor and mild outdoor
A4 stainless (316)	A4-50, A4-70	Plain, passivated	Coastal, tunnels, car parks, food plants

Stainless A2

304

The grade in the photo; general use.

304 304L

Stainless A4

316

Chlorides, de-icing salt and sea air.

316 316L

Carbon steel

4.6 · 8.8

Galvanised for channels and frames.

1022 1035

Alloy steel

Large T-heads

Forged T-head bolts for heavy foundations.

4140 15B35H

Manufacturing

How Our Hammer Head Bolts Are Made

1

Bar & wire

Stainless or carbon steel, certified by heat.

2

Heading

Cold formed up to medium sizes; large T-heads hot forged.

3

Head shaping

Head trimmed to the channel or DIN profile; neck or nibs formed.

4

Threading

Threads rolled; orientation notch pressed into the end.

5

Heat treatment

Quench and temper for 8.8; stainless as formed.

6

Finishing

Passivation, zinc plating or hot-dip galvanising.

Applications

Where Our Hammer Head Bolts Are Used

Façades & curtain walls

Brackets fixed to cast-in anchor channels.

Solar mounting

Rails and clamps on C-profile structures.

Building services

Pipe, duct and cable-tray supports on mounting channels.

Tunnels & rail

A4 bolts in tunnel and catenary channels.

Machine tools

DIN 261 and DIN 186 bolts in table T-slots.

Foundations

DIN 188 and large T-head bolts for heavy machinery.

Quality & testing

Hammer Head Bolt Inspection & Certification

Check	Method	Applied to
Head length, width, height	Callipers: m, n, k	Every lot
Fit in the channel	Trial in a channel sample	Channel bolts
Notch orientation	Visual against the head	Channel bolts
Thread	GO / NO-GO ring gauges	Every lot
Mechanical	ISO 898-1 / ISO 3506-1 tests	Every heat-treatment or material lot
Coating	Thickness gauge	Galvanised lots

Every shipment includes

Mill certificate with heat number
Dimensional report
Lot number on every box

On request

EN 10204 3.1 certificate
PMI report for stainless
Bolt, nut and washer sets

FAQ

Hammer Head Bolt Questions, Answered

A hammer head screw, or T-head bolt, has a long, narrow rectangular head instead of a hex. The head drops into a slot or channel and is turned so that it hooks under the edges, then a nut on the other side clamps the part. DIN 261, DIN 186 and DIN 188 cover the standard types; channel hammer head bolts are made to suit the channel profile.

All three have the same head, for example 26 × 12 × 8 mm for M12. DIN 261 has a plain head, so the slot walls stop it turning. DIN 186 adds a square neck under the head, and DIN 188 adds two nibs under the head; both stop the bolt rotating while the nut is tightened.

Push the head into the channel slot lengthways, turn the bolt 90 degrees clockwise so the head sits under both lips, check the position with the notch in the thread end, then put on the fixture, washer and nut and tighten to the channel maker's torque.

The notch runs in the same direction as the head. Once the bolt is turned, the notch must lie across the channel, at right angles to the slot. If it runs along the slot, the head is not locked under the lips and can pull out.

It depends on the channel maker, but typical combinations are M8 to M12 for 28/15 channels, M10 to M16 for 38/17 and 40/22 channels, and M12 to M20 for 50/30 channels, where the numbers are the channel width and depth in millimetres. Send us the channel profile and we make the head to suit it.

Head length × width × height is 18 × 8 × 5.5 mm for M8, 26 × 12 × 8 mm for M12, 30 × 16 × 10.5 mm for M16 and 36 × 20 × 13 mm for M20. The head width equals the thread diameter; DIN 186 and DIN 188 use the same heads.

As a bolt, the same as any bolt of its size and class: an M12 in class 8.8 has a minimum breaking load of about 67.4 kN (84.3 mm² × 800 MPa). In a channel or T-slot the channel usually fails first, so the safe working load must come from the channel maker's data, not from the bolt.

A2 (304) and A4 (316) stainless steel in classes such as A2-70, A4-50 and A4-70, and carbon steel in class 4.6 or 8.8, zinc plated or hot-dip galvanised. Use A4 outdoors near the sea, in tunnels and in car parks; the bolts in our photo are stainless.