The 762 Club - LYNformation Bulletins
Aware that much development has been going on in the background, but little has been seen in public, and also that the pace of development is gradually increasing, the 762 Club introduced this on-line update feature in early 2013. This page, updated around once a month, will provide brief news snippets, images and general "Lynformation" on our progress. Please come back regularly for the latest updates.
(just hover your mouse over images to see captions, click to see a larger version where available):
See the current and archived versions of LYNformation here:
LYNformation Bulletin No.29: June
Welcome to LYNformation 29.
As is well known, 13 is an unlucky number for many people. It would seem 29 is the black number for LYN.
After a very, very good run of news concerning the building of the new LYN, I am sorry to report four pretty big 'bad news' stories this month, which are not really compensated with much good news at all.
As reported in LYNformation 27, the huge engineering conglomeration Babcock International had agreed to a major sponsorship deal with us to supply the material for the frames, cut, profile, AND assemble it. Sadly, I received a phone call in early May from their new Shipyard Director to urgently go down to Appledore and discuss the project with him. I dropped everything and with much trepidation, travelled to their shipyard to hear what they had to say. Unfortunately, due to a combination of increased workload for their regular business and under-estimating the scale of what they had agreed to, they informed me that they had to row back their commitment.
The good news is that they WILL be supplying most of the material for the frames, apron plate and footplate. Additionally they would also cut and profile all of the parts for us free of charge. However, they have declined to assemble the frames for us. This is not devastating news but it will result in two serious consequences: It will delay the project by at least two months, and we will need to find about an extra £20,000. Urgg!
Once we had this news, I immediately started the process of finding an alternative to take Babcock's cut material and to assemble it. It is not an easy job, as the tolerances are very exacting and there are quite a few parts to weld and bolt together perfectly square and true. In short, there do not seem to be too many who can quote a fixed price to do the work.
Several firms have said they can do it, but only on a per-hour basis, which we cannot afford to entertain. Fortunately, through the good offices of Alan Keef and Sons, the name of A.J. Lowther came up. Although we have not yet placed an order with them, initial discussions do look promising.
Just to add to our woes, I learnt last week that Babcock's plasma cutter had broken down and will take two weeks to repair, further delaying our frames.
2. Eccentrics and Straps
Here, there is good news and bad news. Firstly, the good news is that the eccentric sheaves and straps were getting on well and I am pleased to attach several photographs of the manufacturing process.
Just after these photographs were taken, the parts were sent away to be case-hardened, prior to final machining. Sadly, disaster struck. Once they came back and the straps were machined, it became apparent that something had gone horribly wrong. Tragically, when the first strap was being machined, it fractured in half! Inspection of the two halves of the strap showed brittle cracking. Either the material was wrong or they had been 'over cooked' and the case-hardening was too extreme and not to specification. Fortunately, this cracking occurred on the first strap and none of the others had been machined. Whitelands immediately stopped work and called me for guidance.
We are blessed with two experienced designers, so I passed the problem on to them, and a plan of action was agreed. To give you the full response, I am pleased to include the reply given to Whitelands from Ian Gaylor which pretty much summarises the current position:
It was good to talk through the current situation with the eccentric straps and a route forward.
As I understand it the current situation is as follows:
The brittle facture through the whole of the strap indicates that the heat
treatment has not achieved the specification on the drawing i.e. the raceway
surface at 58-62 HRC and the main body of the strap in the T condition or
equivalent (around 25 HRC). From discussion with Simon Middleton of
Middleton Heat Treatment it doesn’t sound as though making further attempts
to achieve this will be fruitful and there is a risk of cracking the
After discussion with John Scott who is our ICP on this project I would like
to suggest the following as a possible route forward for discussion:
- All 4 pairs of eccentric straps have been made in AISI 01 tool steel
and have been induction heat treated to harden the raceway surface.
- All of the straps have been cut at the bolting joint by wire erosion
and have distorted by shrinking such that when measured across the open arms
of the strap they are approximately 3mm under size.
- 1 pair of straps has been pressed to attempt to correct the
shrinkage and one half has snapped displaying a brittle fracture and one has
If some of the remaining straps are found to be unsound or your heat
treatment supplier has reservations about this approach please let me know
and we can discuss how best to proceed.
- Crack test the 3 good pairs of straps to make sure that they remain
sound and can be used (if not please stop work and advise us of the
- Assuming that the straps are OK anneal them and then correct the
- Re heat treat the straps by through hardening and tempering such
that they are as hard as possible but just ductile (Middleton Heat Treatment
suggest this is just <47HRC) but please could your heat treatment contractor
advise what hardness they recommend and whether any further distortion will
- Crack test the components after heat treating and if OK finish
- Replace the scrapped pair of straps using AISI 01 material.
We now await the response from the heat treatment company and hope against hope that the 3 remaining straps are salvageable, but someone will still have to replace the failed one.
Not good news.
More bad news, I'm afraid.
I have been working with a supplier in China to make the three domes for us under the supervision of a long-standing friend of the LYN project. Sadly, due to the nature of the domes (tightish tolerances), the fact that there are only three to make, and despite promises to the contrary, they have told us that they now cannot make them. They had quoted a very good price and we had someone ready to pay for the shipping but we will now have to start from scratch.
4. Component of the Month
For the first time since it was started, the Component of the Month for May has gone unsold. WE will run it for another month, but then will take it down and try again with something else in July.
OK, bad news over.
5. Eccentric Rods
These have been delivered to us by Nigel Heath (not without some considerable difficulty). During the assembly process, they had become 'bent', and a gig had to be constructed to hold them true whilst they were machined. Even now, there may be some need to tweak them in final assembly. Sadly, like an idiot, I forgot to photograph them when I delivered them to Alan Keef's last week.
6. Cylinders and Valves.
Robert Frosts continue to make slow but steady progress over in Norwich. As you can see from the latest batch of photographs, the valve liners have been machined and are ready for freezing in. This is the last 'big' bit of machining. The final chronology will go something like:
Freezing the liners in - Honing the cylinders - Drilling and tapping the drain cocks threads - Pressure Testing
In all about six weeks to go before delivery.
7. Reverser Indicator Plate
The reverser indicator plate has been completed and delivered. This will now be assembled at Alan Keef's and we hope to have photographs of the finished Reverser assembly in the next month or two.
Sorry it has been a poor month, but I very much hope we have better news soon.
See the current and archived versions of LYNformation here:
Copyright © 2009 - 2017, The 762 Club Ltd. Page last updated: 10 Jun 2015
(News page and last updated: 26 May 2017)
Company registered in England, No. 7401325 Registered office: 12 Culm Close, Bideford, EX39 4AX
Registered as a Charity with the Charity Commission for England & Wales under registration number 1139839