Titanium (Ti)

Throughout my life working on aircraft I have used Titanium bolts. They are used for a number of reasons two being strength and lightness. The Ti that we used on military aircraft was about a third of the weight of a steel bolt of the same size, and was coloured a blue/grey. The picture below shows three titanium bolts that were laying about in the bottom of my toolbox with one steel one as a colour comparison. The titanium ones all together weigh about the same as the single steel bolt.

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The place where titanium is very useful is in very high heat areas like exhaust systems and jet engines. I have, in the past, heated one of the Ti bolts up till it was glowing red and hit it with a lump hammer, that did not even distort the threads and I could screw a nut onto it by hand afterwards.

Titanium is freely available these days from many places as people want lighter bicycles and lighter parts for racing motorcycles. The wheels and tyres are a great place to save weight as lighter a front wheel is, the more it will stay in contact with the road over uneven surfaces and the less gyroscopic effect the spinning wheel will have on the control of the bike.

Back to the reason for this post. The four bolts holding the brake callipers on my 848 looked a bit tatty, the chrome was scuffed in places and although most people would never notice, I did. I looked into changing them. I could buy 4 bolts claiming to be titanium from ebay China for the same price as it would cost to buy one of those bolts from the leading company in titanium fasteners in the UK. The link to the ebay ones is HERE.

They arrived today so the first thing that I did was weigh one against an old steel one as fitted to the bike, the pictures are next.DSCN0483

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As you can see there is 15 grams difference, that makes 60 grams for all four – this bike should fly with all that weight saving 🙂

The next picture shows the difference when fitted.

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The top bolt is the steel and the bottom one titanium.

All the super bike racers out there are now going to want to know about the huge performance increase with these fitted, well after going out for a spin and a coffee, the bike feels exactly the same as it did before. It may be the fact that I drank a small coffee but it could be that the 0-60 acceleration was 0.00000000000007 seconds slower afterwards, but there again I had €1.20 less coins in my pocket. I must stop being sarcastic about people spending a small fortune on carbon fibre to save the weight of half a litre of fuel!

My aim was achieved, the bolts look nice.

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2 thoughts on “Titanium (Ti)

  1. Leonard Assink July 18, 2016 / 4:44 am

    Does Ti have any of the same problems of galvanic corrosion with aluminum as steel does over time? I replaced a handful of bolts on my ST4 as the original ones had begun to corrode and strip the threads from the aluminum sleaves. Based on the article from the British Stainless Steel Association (link below), I would expect the galvanic corrosion characteristics would be worse with Ti, but I have no practical experience. I’m curious because I’d rather use Ti bolts as replacements to prevent rust from rain and salt.
    http://www.bssa.org.uk/topics.php?article=89.

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    • rouffignac July 18, 2016 / 6:01 am

      If two different metals are together and the moisture is added then you will get corrosion, that is how a battery works. There is a product that is similar to a PTFE grease that the aircraft industry uses when assembling parts to stop the ingress of moisture. Ti is perhaps less aggressive than most metals as it is quite inert in most cases. Ti fasteners are used on all military aircraft to bolt aluminium together without problems. The only thing to avoid with Ti is cadmium plate, an anti corrosion coating applied to steel, as it can affect the Ti.
      Trouble with Ti is the price, all of it is an alloy and the cheaper stuff is obviously a poorer quality. Ti is best used on very hot areas as it is unaffected by heat, exhaust nuts and bolts would be a prime location for it. It is used in the jet pipe areas as Ti sheet on some aircraft. I have heated an aircraft grade Ti bolt with a blowtorch until glowing red and hit it with a hammer. After cooling a nut could still be fitted to the bolt as the threads were not even distorted.

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