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The Pro Hex Head Screw vs Coach Bolts – Coach screws comparison

Have you ever wondered which is best to use for fixing timbers, a coach bolt or a hex head screw? The answer: they both do the job and can fix timbers securely, but there is clear winner when it comes to materials, strength, application time, reliability, ease of use and the number of tools needed.

So which method comes out on top? We’ve put together a comparison below:


Coach Bolts: Coach bolts are primarily made of carbon steel, however, this is often a lower grade of steel than hex head screws and as a result, they are often M10 or larger to compensate. This means a lower grade of steel can be used to achieve the level of strength required.

Coach bolts can undergo a number of techniques to enhance corrosion-resistance and strength, ensuring a degree of durability and structural performance. Generally, they are zinc plated/galvanised which gives an element of corrosion resistance, however, they will corrode over time.

The Pro Hex Head: The Carpenters Mate Pro Hex Head screws have been coated in Geomet 500, which is proven to last 2,000 hours in salt spray and ensures your screws can withstand corrosion to a much higher level. We also offer 316 grade stainless steel Hex Head screws that have a higher % of titanium when compared with most stainless steel products for increased anti-corrosion and strength properties in high salt areas.

Our Pro Hex Head and HD Hex Head screws are made from C1022 steels, which have a higher carbon and manganese content than basic C1020. This provides greater strength and ductility, ensuring the screws can flex with the structure over time.

Every Carpenters Mate steel screw have been through a ‘case hardening’ heat treatment which is a far more controlled method than the traditional ‘through hardening’ treatment. Case hardening provides a hardened case for ease of drilling whilst retaining a ductile core, in order for the screws to move without failure.

Winner – The Pro Hex Head


Coach Bolts: In terms of strength, the coach bolt timber connection is very strong and sturdy. This is why this method has been used for so many years when creating timber structures – it’s proven to create strong connections.

The Pro Hex Head: One of the first questions a carpenter would say when introduced to a hex head screw is ‘surely it’s too thin to be as strong as a coach bolt.’ This certainly isn’t the case. Hex head screw timber connections are proven to be just as strong as coach bolt connections and this is easily proven with the Carpenters Mate MyCalcumate app.

Winner – Draw!

Application Time

Coach Bolts: You’ll need to complete the following steps to fix timbers together using coach bolts: Drill a hole through your timbers, hammer a bolt through the hole, insert a washer and a nut, and finally tighten, the nut using a spanner, and repeat – a lengthy four-step process. Additionally, you may be required to grind the excess to make sure the end of the bolt doesn’t protrude too far.

Approximate time taken per connection: 2mins30 seconds

The Pro Hex Head: The Pro Hex Head screw has been designed to be self-drilling through any wood-to-wood application and comes complete with a free drive tool in every pack. With no need for washers and bolts or pre-drilling, and the correct drill-bit included with every purchase, these screws have been specifically designed to save time. Our pro hex head screws are perfect roofing and landscape, for more information take a look at the rest of our roof screws and landscape screws

Approximate time taken per connection: 30 seconds

Winner: The Pro Hex Head

Reliability and longevity

Coach Bolts: Fixing timber structures using coach bolts provides limited security against the fixture loosening. A washer is also used to distribute pressure to ensure the material retains its flatness and prevent the pull-out of the screw. However, time and natural movement will encourage the coach bolts to loosen, increasing the level of security risk to the structure. If the timber shrinks due to natural changes in temperature and moisture, the nut can move around, losing the integrity of the connection. Although a coach bolt offers greater resistance to pull through, it’s not guaranteed for life of project.

The Pro Hex Head: You’ll find that the thread is found only at the end of the screw – not all of the way up. This allows timbers to flex and twist, which is a natural process for timber as the external temperature changes. This ensures that the connection remains strong at all times.

All of the Carpenters Mate products are specifically engineered to be used in specific applications and go through thorough testing to ensure they’re proven to work every time. There is no need to worry about screws breaking or time being wasted by digging out failed screws from your timbers – Carpenters Mate products are tried and tested by industry professionals and rated as one the most reliable timber screws on the market. Remember, they can also be reused in other projects and are guaranteed for the life of the project.

Winner: The Pro Hex Head

Tools Needed

Coach Bolts: When fixing timbers using the traditional method, you’ll need the following tools: a cordless drill and drill bit, a bolt, a washer, a nut and a hammer, a spanner and possibly a grinder too – that’s 4 tools and 3 additional components needed to complete one job.

The Pro Hex Head: All you need is a cordless drill. Zip the screw in between the adjacent timbers and you’re done!

Winner: The Pro Hex Head

Ease of Use

Coach Bolts: Using coach bolts can be a fiddly job when it comes to fastening your timber, especially in confined places. It can be tricky work muddling your way behind timber structure to fasten the bolts, which often takes time and a lot of patience and potentially poses a health and safety risk.

The Pro Hex Head: Aside from the reduced number of tools, the Pro Hex Head has a fast installation time and there is no need to get behind the timber with bolts or washers to secure the fixture. Simply secure your fixture by using the provided drill-bit and drill your Pro Hex Head screw into the timber – as quick and easy as it sounds.

Winner: The Pro Hex Head

The Final Score

 The Pro Hex HeadCoach Bolt
Application Time 
Reliability and Longevity 
Tools Needed 
Ease of Use 

So why not give a hex head screw a go? Carpenters Mate Hex Head screws are designed with reliability, safety and efficiency in mind to make construction projects quicker, cleaner and more accurate.

That’s not all…

  • Our Hex Head screws come in a range of sizes to support UK timber sizes.
  • Each screw has specially designed thread pitch and a type 17 slash point, which has a unique sharp point for fast drilling, therefore ensuring a cleaner finish.
  • One free drill-bit (correctly-sized for your screw) is included with every box.

Our Hex Head self-drilling wood screws are perfect for:

  • Laying substructure for flooring and decking
  • Completing loft conversions
  • Repairing roofs
  • Erecting fences
  • Any other timber framing or connection

Find a local distributor

If you’re interested in our range of Carpenters coach screws you can pick up a pack from your nearest distributor here.

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