What You Need to Know About Nuts & Bolts For Restoration

One of the best things that I have learned is how to identify and organise nuts and bolts for restoration. I cannot believe it has taken me this long to understand all the different types of nuts and bolts that you get. For many years I have just fumbled along never really knowing and understanding the nuts and bolts properly. But now I realise its actually very simple.

Learning about Bolt Types

I can’t believe how much time I have wasted by not knowing this.

  • looking for the wrong bolts
  • trying to fit nuts on the wrong bolts
  • choosing the wrong spanners
  • and worst of all using the wrong bolt for the wrong application.

Let me explain this in the most logical and simple way that helped me understand. I am not an engineer so don’t expect perfect definitions here, you can research that on the internet. At the end I will explain all my lessons learned in how not to manage the nuts and bolts in a restoration and the easiest way that I have found to do it.

The most common bolts I have encountered are metric bolts. Then I had also heard of imperial and UNF from working on older landies, and I thought that was it. Then when I started working on the Series 1 I encountered Witworth bolts which none of my spanners fitted.  What made it even more confusing was that they had similar nomenclature like ¼, 7/16, 5/8 etc but were different. This is when I started to pay attention.

History of bolts and thread types

The first bolts used were Whitworth invented in 1842 by Joseph Whitworth. They were called British Standard Whitworth or BSW and had a fairly coarse thread. In 1908 a fine thread version was introduced and called British Standard Fine or BSF. In 1948 after World War 2 the world nations cooperated to introduce a unified standard called Unified Thread Standard (UTS) with UNF and UNC nomenclature. At the same time the metric standard was introduced and used mainly in Europe and Asia.

Now days 60% of bolts are metric used by most of the world except for USA and Canada who still use Unified bolts accounting for 30% of bolts. All other bolts make up the balance of 10%.

I have always been familiar with metric and imperial from a spanner point of view but have never understood the threads. Aren’t you always fascinated by the guys at the bolt shop, who just look at a bolt and know what it is? I thought they were real bolt gurus. Let me show you how simple it really is to be a bolt guru.

Identifying Bolt Types

Obviously there are many different types and manufacturers of bolts. But when you look at automotive applications then it’s a bit easier to narrow down.

The are really only 3 major distinctions in all bolts

  1. Thread type
    • Imperial (British Standard)
    • UTS/SAE (Society of Automotive Engineers)
    • Metric
  2. Fine or coarse thread
  3. Bolt strength

To identify the bolts you have to look at what is on the head of the bolt

For automotive applications only the hi tensile bolts should be used. So any bolt without a marking on is most likely unsuitable. The high tensile bolts are much stronger, resist corrosion better and will not fail under shock loading.

Critical component bolts should be minimum British class T, Unified SAE grade 8 or Metric 10.9.

So simply speaking you have a choice of 3 bolt standards giving you 6 bolt types in total

  1. British Standard Whitworth – BSW or BSF
  2. Unified – UNC or UNF
  3. Metric – Coarse or Fine

The Series 1 Land Rovers all have mostly BSF bolts with some BSW on the aluminum gearbox sections

One of the best references that I came across recently is Geoffrey Croker’s “The Great Thread Cutting Chart.

The best way to Organise Bolts For a Restoration

Normally what I’ve done when I dismantle a vehicle is try and keep everything together and then just put it in a packet a label where it came from. But what happened this time is I did that and I put a number on each packet but then lost the list explaining what it is. So I landed up with a whole lot of packets with numbers on and I didn’t know what what they were.

Since then I have come up with a better system. I’ve gone back to the parts manual and had a look at that and made a list of everything that’s needed. It is a list of all the different bolts that I need and the sizes.

The best way to do it as far as I’m concerned is just remove all the bolts nuts and washes. Don’t worry about keeping them together, remove them all. Then clean them, and check which ones you can keep and which ones are missing. Take stock of what you’ve got and then get the extra ones that you need for replacements. Then you get all of those off to the electroplater get them electroplated and when you get them back you can sort them out.

Use the parts catalogue, not the manual, because the parts catalogue shows you exactly which bolts go where. You can package them for the assembly process so when you come to put the different parts on you’ll have all the bolts in the right place. That is the way I would do it in the future. Let me know in the comments below how you’ve done it and how you do it and if you’ve got any better tips and tricks that we should be using.

You can watch the full video here on my channel The Overland Legend

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