Buy A4 Stainless Coach Screws | M8 x 100mm A4 Stainless Lag Screws

M8 x 100mm A4 Stainless Hex Head Coach Screws DIN 571

A4 (316) Marine grade stainless steel

Rust resistant for exterior use

13mm Hexagon head

ORDER BY 3PM FOR NEXT DAY DELIVERY (MON-FRI)*

ORDER BY 3PM FOR NEXT DAY DELIVERY*

FREE STANDARD DELIVERY ON ORDERS OVER £100*

FREE STANDARD DELIVERY OVER £100*

Description
Delivery

What are Coach Screws?

A Guide to Marine Grade A4 Stainless Steel Lag Bolts and Their Uses

Coach screws (also known as lag screws or lag bolts) are essential heavy-duty fasteners primarily used in timber-to-timber construction. These robust screws feature a hexagonal head, making them ideal for high-torque applications. When you need extra strength and rust resistance for outdoor projects, A4 stainless steel coach screws are a top choice, especially in very corrosive environments such as coastal areas, applications exposed to chemicals i.e. swimming pools, or areas exposed to excessive temperature fluctuations.

Key Applications:

Securing metal plates or concrete posts to timber
Heavy-duty timber-to-timber applications
Fixing into masonry when used with a nylon plug
External applications, or for use in corrosive environments

Why Choose A4 316 Stainless Steel Coach Screws?

A4 (316) stainless steel is commonly known as 'marine grade' stainless steel, as it can be used in salt water environments
Ultimate rust resistance for outdoor use - A4 stainless has better rust resistance than A2 stainless
Stainless steel is essential when working with oak and other hardwoods with a high tannin content
Ideal for projects exposed to harsh weather or moisture, chemicals or heat exposure

Important Note: While stainless steel offers excellent corrosion resistance, it’s softer than carbon steel. For best results, always use a pilot drill, especially in hard woods like oak.

Specifics

Diameter (d1): Ø8mm (M8)
Length from under head (L): 100mm
Head height (k): 5.5mm
Across flats (s): 13mm
Across points (e): 14.2mm
Thread length: See diagram for indication. Please call us for exact measurement of current stock as it varies by batch
Material: A4 (316) Stainless steel
Din standard: DIN 571

Click here to view the full sizing table

Technical line drawing of A4 stainless steel coach screws

Delivery Options

TC Fixings Ltd offers a range of delivery services across the UK to suit different order sizes and delivery times. Orders are dispatched using reliable courier and postal services to ensure products arrive quickly and safely.

Delivery Summary

Free delivery: Orders over £30 nett qualify for free delivery
Same-day dispatch: Orders placed before 15:00 Monday–Friday are usually dispatched the same day (subject to stock availability)
Collection: Available from our premises
Local delivery: Free van delivery available in Saffron Walden and surrounding villages

Free Delivery

Orders over £30 nett qualify for free delivery.

If your order is close to the threshold, adding additional items may allow you to qualify for free delivery.

Free delivery applies to standard mainland UK delivery only.

Delivery Charges

Orders under £30 nett are subject to carriage charges. Available delivery options are shown below.

Royal Mail Services (Up to 2kg)

Service	Delivery Time	Cost
Royal Mail Standard 48 Tracked	3–5 working days	£4.99
Royal Mail 24 Tracked (Most Popular)	1–3 working days	£5.99
Special Delivery by 1pm	Next working day	£14.99
Special Delivery by 9am	Next working day	£49.99

Royal Mail services are available for consignments up to 2kg.

Courier Services

Service	Delivery Time	Cost
Standard Courier	2–3 working days	£6.98
Express Delivery (Most Popular)	1–2 working days	£8.99
Next Working Day by 13:00	Next working day	£10.99
Next Working Day by 11:00	Next working day	£14.99
Saturday Delivery	Saturday	£9.98

Orders placed before 15:00 Monday–Friday are normally dispatched the same working day, subject to stock availability.

Delivery Surcharges

Additional charges may apply in certain circumstances.

Extended Delivery Areas

Orders to the following locations may incur additional delivery charges:

Isle of Wight
Isle of Man
Scottish Highlands
Scottish Isles
Northern Ireland
Channel Isles

These charges will be shown at checkout where applicable.

Long Item Surcharge

Items measuring 1.5 metres or longer are subject to a £12 length surcharge per shipment.

Dispatch Information

Orders placed before 15:00 Monday–Friday are normally dispatched the same working day when all items are in stock.

Orders placed after this time, or on weekends and bank holidays, will be dispatched on the next working day.

Next working day delivery services apply Monday–Friday excluding bank holidays.

Collection

Customers may collect orders from our premises.

Collection orders are normally ready within 1 hour, provided all items are in stock. Please wait for confirmation before travelling to collect your order.

Local Van Delivery

TC Fixings offers a free local van delivery service to customers in Saffron Walden and surrounding villages.

Please contact our team for further information if you are located in this area.