At Arun Fasteners we are often asked about the thread length on differing size Hex Head Bolts.  Below is a helpful guide.

NOTE: It is measured from UNDER the head

Metric Bolt Thread Length

0 to 125mm
2 x Diameter + 6mm
125 to 200mm
2 x Diameter + 12mm
200+mm
2 x Diameter + 25mm

Imperial Bolt Thread Length

Thread length = 2 x diameter + 1/4" (up to 6"), 2 x diameter & 1/2" (over 6")

NOTE: It is measured from UNDER the head

 

New stock

In 2021 we were lucky enough to purchase 8 tonnes of British steel fasteners.

Approached by a farmer’s family in Cheshire, and not being exactly sure what we were buying, we are delighted with our new treasure trove!

Consisting of UNC, UNF, Whitworth, BSF and Metric, in a complete variety of bolts and nuts.

We are still sifting and cataloguing it all, but we do know that the vast majority originated from the Alvis Military Factory in Coventry.

We are delighted to have saved these high quality British fasteners from the scrap man. Our hope is they will fulfil their purpose and be used in restoration projects worldwide.

A little history of Alvis

Originally a stationary engine factory, by the end of the 1920s they had progressed to sports cars winning at Les Mans.

On November 14th 1940 the car factory was severely damaged by the German Luftwaffe’s raid on Coventry although the armaments factory was relatively undamaged.  Car production was suspended for the duration of the war only resuming during the latter part of 1946.  But Alvis carried out war production on aero engines and other aircraft equipment.

Alvis designed a series of six-wheel drive vehicles. The Saladin (FV601) armoured car and Saracen armoured personal carrier were first.  The Salamander was an airfield crash tender. It was subsequently used as a basis for Stalwart amphibious military truck.  The FV611 model was also built to serve as an armoured ambulance.

The Combat Vehicle Reconnaissance (Tracked) family of tracked vehicles were designed in the 1960s.  The family includes FV101 Scorpion, FV102 Striker, FV103 Spartan, FV104 Samaritan, FV105 Sultan, FV106 Samson, FV107 Scimitar, FV4333 Stormer and the Streaker.

AVF Society

Established in 2005, the Alvis Fighting Vehicle Society is the largest collection of Post War tanks and fighting vehicles in the UK.  These vehicles are privately owned or part of collections.  The society functions to pool and share its resources, for the purpose of Restoration, Preservation and Education.

 

With another batch of Whitworth nuts despatched to a vintage locomotive restoration charity, we thought we would look into the history behind the thread within this era.

The Whitworth thread refers to a thread standard developed by Sir Joseph Whitworth, a prominent British engineer and inventor in the 19th century. Whitworth made significant contributions to the field of engineering, and his thread standard was one of them. This thread system was widely adopted in Britain during the Victorian era and had a substantial impact on manufacturing and engineering practices.

Within the railway, the Whitworth thread was employed in various components of rail infrastructure; the construction and maintenance of railway tracks, bridges, and rolling stock.  It had some distinct characteristics, such as a 55-degree thread angle and rounded crests and roots. This design made it more robust and less prone to damage compared to some other thread standards of the time. The standardisation of threads was crucial for ensuring that parts produced by different manufacturers could be easily exchange and replaced.

As technology and standards evolved, Whitworth threads were gradually replaced by other thread standards, such as the metric system and the American Unified Thread. However, you will still encounter Whitworth threads on vintage railway equipment, with enthusiasts and preservationists using them in valuable restoration projects to maintain historical accuracy.

We are lucky to have an extensive stock of Whitworth nuts, bolts and socket screws, shop here https://arunfasteners.co.uk/

Whitworth Threads per Inch (TPI)

Diameter TPI Diameter TPI
3/16” 24 ¼” 20
5/16” 18 3/8” 16
7/16” 14 ½” 12
5/8” 11 ¾” 10
7/8” 9 1” 8
1 1/8” 7 1 ¼” 7
1 3/8” 6 1 ½” 6
1 ¾” 5 2” 4 1/2
2 ¼” 4 2 ½” 4

 

 

 

We are often asked what size hex Allen key wrench will fit a certain socket screw. Below is a conversion chart to help:

Metric Socket Cap Screws

Thread Diameter Size Allen Key Wrench Size
M2
1.5
M2.5
2.0
M3
2.5
M4
3.0
M5
4.0
M6
5.0
M8
6.0
M10
8.0
M12
10.0
M14
12.0
M16
14.0
M20
17.0
M24
19.0
M30
22.0
M36
27.0
M42
32.0
M48
36.0
M56
41.0
M64
46.0

Metric Socket Set (Grub) Screws

Thread Diameter Size Allen Key Wrench Size
M2
0.9
M2.5
1.3
M3
1.5
M4
2.0
M5
2.5
M6
3.0
M8
4.0
M10
5.0
M12
6.0
M14
6.0
M16
8.0
M20
10.0
M24
12.0
M27
14.0
M30
14.0
M36
17.0

Metric Socket Button Screws

Thread Diameter Size Allen Key Wrench Size
M3
2.0
M4
2.5
M5
3.0
M6
4.0
M8
5.0
M10
6.0
M12
8.0
M14
8.0
M16
10.0
M20
12.0
M24
14.0

Metric Socket Button Screws

Thread Diameter Size Allen Key Wrench Size
M3
2.0
M4
2.5
M5
3.0
M6
4.0
M8
5.0
M10
6.0
M12
8.0
M14
8.0
M16
10.0
M20
12.0
M24
14.0

Most metric High Tensile (HT) nuts and bolts are produced in three grades, with the exception of mild steel.

Mild steel Grade 4.8 is the common starting grade for most threaded bar and square cup bolts (coach bolts).

Next is the starting High Tensile Steel Grade 8.8 which most bolts and H.T Hexagon Set Screws are manufactured to for general purpose use.

For more Tensile strength the next Grade up is 10.9, used in many fastener applications such as vehicle tow bars and suspension components.

The 3rd and strongest high Tensile Grade is 12.9, used in heavier fastener applications such as agricultural machinery and commercial vehicle components.

The high Tensile strength of a bolt is best protected by leaving the steel unplated. This doesn’t provide any form of corrosion protection apart from the natural oils created at point of manufacture.

If you are looking to replace a bolt and are unsure of what grade it is, you can often find the grade stamped on top of the head.

Arun Fasteners has a large range of high tensile, including 10.9 and 12.9 fasteners on our shelf. For a quote and availability call us on 01243 551484 or email info@arunfasteners.co.uk.

Arun Fasteners has a counter service available for local businesses and trade people.

We stock everything listed on our website within our warehouse so we can meet many urgent requirements.

We operate an ‘all orders in advance‘ approach to avoid customers needing to wait. Simply phone or email your order through, alternatively complete your order online and choose click and collect.

Click and collect orders will be available to collect after 10am the next day, but if your order is urgent simply call us to arrange.

We do not offer a walk in general public service.

75 years on from its creation, Units 2-3 Ford Lane Industrial Estate, continue to sell fasteners of every size and description.

Its conception came about post 2nd World War. Ivor Green, with an entrepreneurial spirit and a background in the Armed Forces, saw an opportunity when the government started selling off surplus supplies, and Ivor Green Exports was born. 

That tactic continued into the 70s and 80s when the shipyard industry was slowing down and closing.  He joined forces with another fastener entrepreneur in Scotland, A.Winston, and together they bought up tonnes of fasteners.  They continued working together, trading back and forth, depending on what their customers needed.  At that time it was all BSF, BA and Whitworth stock – the threads required in the British made machinery.

As American investment increased post war, factories were built housing their machines, which all required UNC and UNF threads. So Ivor included stock of these items, whilst increasing his export business of the imperial threads.

After the UK joined Europe, the need and use of Metric and Metric Fine threads escalated, and many players joined the fasteners business.  Ivor Green, who had been joined by his son Alan, continued to thrive selling off his vast stocks of Imperial stock word wide.

In the 90s Jon Bazley came to work for Alan, and after several years working together, Jon bought the business, and Alan enjoyed his retirement in France and the UK.

Jon changed the name to Arun Fasteners and ran it solely, later joined by his brother Dave, for over 16 years. Jon had a wealth of knowledge and helped maintain relationships with local companies.  He then decided to retire.

In the meantime Chris and Claire White were on the lookout for a business to buy. Chris who had been working as an aftersales manager for Harwoods Land Rover for over 26 years was ready for a change and to be his own boss.  Claire trawled the internet looking for business opportunities and initially dismissed a fasteners company, unsure exactly what it meant!  Eventually, she forwarded the information to Chris who nearly fell off his chair!  The initial meetings happened swiftly and they couldn’t believe the luck that it was just 5 mins from their home in Fontwell.  The business sale went smoothly, and although daunted by the learning task before them, they were grateful for the 6-month support from Jon during the handover.  They saw huge potential as there was no internet presence and no history of marketing.

After working extremely hard learning the difference between all the 16000 different types of boxes on the 4000 sq foot warehouse shelves, and installing an electronic stock and invoice system, the company is now moving forwards in leaps and bounds.  They’ve taken on a new full time employee who is helping hugely re-organising the stock and serving our loyal customers.

They are stocking more types of woodscrews, self drilling screws, stainless, galvanized products and consumables.

Their young son Joseph loves coming in to help, whether it’s crawling around on the floor with a huge magnet collecting dropped stock, or smiling sweetly at customers counting their orders and pocketing good tips! The family dog Lola is often at work demanding customers attention and enjoying the sun. “We are excited about the future of Arun Fasteners, and are grateful to our loyal local customer base, as well as the new companies we are working with in the UK and abroad”.

 

Below are common imperial washer dimensions

Imperial T3 Light Washers Imperial T3 Heavy Washers
I/D “ O/D “ Thickness “ I/D “ O/D “ Thickness “
1/8 5/16 1/32 1/4 0.55″ 0.06″
3/16 25/34 1/32 5/16 0.62″ 0.08″
1/4 9/16 3/64 3/8 0.75″ 0.07″
5/16 5/8 3/64 7/16 0.86″ 0.09″
3/8 3/4 3/64 1/2 0.99″ 0.09″
7/16 7/8 1/32 9/16 1.12″ 0.09″
1/2 1 1 1/6 5/8 1.24″ 0.11″
9/16 1 1/8 1/32 3/4 1.50″ 0.12″
5/8 1 1/4 5/64 1 1.87″ 0.16″
3/4 1 1/2 5/64
1 1 7/8 5/64

 

Imperial T4 Heavy Washers Imperial T4 Light Washers
I/D “ O/D “ Thickness “ I/D “ O/D “ Thickness “
3/16 1/2 1/16 3/16″ 0.49″ 0.04″
1/4 5/8 1/16 1/4″ 0.62″ 0.04″
5/16 3/4 5/64 5/16″ 0.75″ 0.05″
3/8 7/8 1/16 3/8″ 0.87″ 0.05″
7/16 1 3/32 7/16″ 1″ 0.05″
1/2 1 1/8 3/32 1/2″ 1.12″ 0.05″
5/8 1 3/8 1/8 5/8″ 1.36″ 0.07″
3/4″ 1.62″ 0.07″
1″ 2.10″ 0.09″

Arun Fasteners have been working with M&J Engineering. (Engineering and fabrication specialists on the South Coast.)

They’ve shared some images of their turf lifter.

Coming Friday 10am

Please see below measurements relating to our most common metric washers

Metric Form A Washer DIN 125 Metric Form C Washer DIN125C
Size I/D mm O/D mm Thickness mm Size I/D mm O/D mm Thickness mm
M3 3.2 7 0.5
M4 4.3 9 0.8 M4 4.3 10 0.8
M5 5.3 10 1 M5 5.3 12.5 1
M6 6.4 12 1.6 M6 6.4 14 1.6
M8 8.4 16 1.6 M8 8.4 21 1.6
M10 10.5 20 2 M10 10.5 24 2
M12 13 24 2.5 M12 13 28 2.5
M14 15 28 2.5 M14 15 30 2.5
M16 17 30 3 M16 17 34 3
M18 19 34 3 M18 19 37 3
M20 21 37 3 M20 21 39 3
M22 23 39 3 M22 23 44 3
M24 25 44 4 M24 25 50 4
M27 28 50 4 M27 28 56 4
M30 31 56 4 M30 31 60 4
M33 34 60 5 M33 34 66 5
M36 37 66 5 M36 37 72 5
M39 40 72 6 M39 40 77 6
M42 43 78 7
M45 46 85 7
M48 50 92 8
M52 54 98 8
M56 58 105 9

Arun Fasteners have been working with M&J Engineering, engineering and fabrication specialists on the South Coast.

They’ve shared some images of their turf lifter which is quite a beast I’m sure you’ll agree!

Included in the re-fit are our:

Metric set screws and bolts in zinc and stainless steel

Metric socket button screws

Metric flat form A washers

Metric hexagon full nuts

Split pins

The larger fixings include:

M24 studding (threaded bar) and M24 hexagon full nuts

M30 high tensile hexagon bolts have gone in the height control ramp

We would like to thank M&J Engineering.

If you are a customer and would like to feature in our monthly blog. email info@arunfasteners.co.uk

Happy Fathers Day to all the dads, especially our very own Chris.