‘The Eagle has landed safely.
The World is filled with them, the project that it is intended to get around to when there is time.
They range from large government and corporate projects to individual mundane jobs such as tidying the workshop, working around the house, finishing something, starting something else, in fact anything that isn’t done immediately falls into the roundtoit category.
Bill Watterson summed up the challenges when he wrote: ‘God put me on this earth to accomplish a certain number of things. Right now I am so far behind that I will never die.’
Here is one of my roundtoits, the completion of an ‘O’ gauge live steam un-rebuilt ‘Royal Scot’ to the design of Martin Evans.
For some time this photograph of the rolling chassis adorned my website under the heading of projects on the go. I eventually removed it as it never progressed.
At last I have got aroundtoit and we are making progress.
Click here to read all about it.
One of the leaf springs of a 5″ locomotive had suffered with water ingress and it was noticeable that this had affected the performance of the said spring under load.
It was estimated it needed to handle a load of 14 lbs and when this was progressively applied the spring first flattened and then bowed. When the spring was dismantled the individual leaves were found to be badly corroded. It was decided to make a new one.
The theory of making a leaf spring is pretty straight forward. Obtain suitable steel strip in the annealed (soft) state which makes any cutting and drilling straight forward, harden the leaves by heating to cherry red, quench, clean then temper the hardness by reheating to a blue / grey colour and quench.
Reading up various model engineer publications and internet forums I decided to give the production a go and to describe the methodology I came up with.
Before I describe the process though, there is one point that does not seem to be covered in the descriptions and so I pass it on first as I discovered it after I had made a couple of leaves, which initially was a little disconcerting. On flexing the fully tempered leaves to my amazement two of them bent! Initially I thought that perhaps the colour I had tempered to was wrong. I cleaned up the leaves and re-tempered them, this time checking the colour was a nice blue / grey all over. Nope, still bent. Now I was a little stumped, but I decided to clean them up again and this time re-harden them to cherry and then temper. Applying the heat I made sure that the whole leaf was cherry red and that when it was quenched it was totally immersed at cherry red. In other words there had been no localised cooling before quenching. This did the trick.
The learning points of this were:
- Make sure the leaf is cherry red all over when it is quenched in oil
- Check the leaf after quenching and before tempering by flexing it
- If it bends, re-harden
- Make sure that you have sufficient depth of quenching oil to cover the leaf – this is a consideration if tempering a number of leaves. As the ‘pile’ grows bigger in the oil the leaves may start to sit out of the oil at one end for example.
The equipment I used was as follows:
Go System DIY blow torch for heating the spring leaves during hardening and for any additional heat you may require during the process.
Ground Nut Oil for quenching. A high temperature cooking oil that does not smoke or burst into flames when the hot parts are dropped in. Added bonus of a smell of deep frying!
Three 7″ ∅ steel cake tins. Two used for sand tray & cover (invert one on top of the other) and one for holding the quenching oil.
Aladdin Paraffin Stove. Surprisingly (to me!) this at full bore raised the temperature of the sand tray to 350°C which was ideal for getting the correct tempering colour. Added bonus of providing good heat in the workshop on a freezing cold day too!
Tala Oven Thermometer for accurately getting the correct temperature in the sand tray rather than relying on your judge of colour.
Thick leather gardening gloves for handling the hot trays etc.
Safety glasses or goggles to protect your eyes just in case of spits from the oil.
Pliers or tongs for handling the hot metal spring leaves
In photographs, the sequence of events was:
The individual leaves were then heated to cherry red and quenched in the oil.
The original oil container was too small and as the leaves accumulated the latter ones were not fully submerged. The container was changed to a 7″ ∅ cake tin.
As can be seen the temperature is nearly at the required 350° C. The lid helped the temperature to rise more quickly. All leaves were covered in sand to even out the heating. The process took about 40 minutes and would handle 9 leaves at a time.
The original oil bath tin was from a Fray Bentos Steak & Kidney Pudding, but although it looked deep by the time 9 leaves were in it was too small.
Colours on the right don’t show well due to the artificial light in the workshop, but you get the idea.
On the left can be seen the steel leaves on the left and the ‘Tufnol’ leaves on the right.
Five steel leaves & twelve ‘Tufnol’ leaves gave the correct torsion as can be seen on the right when the 14 lb load was applied.
In conclusion the production of a working leaf spring was not as difficult as I was first led to believe. Provided you can work out how much weight it is to carry, then by testing with an appropriate load you can work out how many steel leaves you will require. Which seems to me to be better than ‘They are very hit or miss, you will find once you are up at the track you may need to add more leaves’ as one designer wrote……..
Hope you had a good holiday and the weather suited you. I have attached a few photo’s to show the model on it’s base, and all I did was sand a hole for the plastic stand so the legs of the model just rest on the Lunar surface. So with my effort to find you and your splendid effort to restore it we’ve saved a rare model which can’t be bad.
Purchased last year, I have found this the most fantastic camera for taking very good quality video. I have fixed it to my various live steam models (5″ gauge steam locomotive and 2″ scale traction engine) for footplate views.
Not the steadiest of platforms when moving which makes the results even more incredible, such steady films for posterity.
The other evening I hit a technical glitch when transferring the files from the camera to my computer. Mid transfer the GoPro froze, the computer flashed up the message ‘USB device not recognised’. Disconnecting the GoPro it refused to turn off or do anything, the two arrows indicating file transfer remained frozen in the window. On this model access to the battery did not seem possible and removing the SIM card and then replacing it did nothing either.
The GoPro website did not provide any solution either. Consternation, choice language and depression. Have I lost my latest clips?? As it was still under the guarantee I got the receipt out ready to take to the shop for exchange.
As I could not turn the darned thing off it remained on overnight. When I checked it in the morning the battery had discharged and the screen was now blank (obviously!). I decided to reconnect to the computer and see what happened. Yeah! It sprung into life and completed the downloads.
The reason for posting this? It may help someone else if they have the same issue or similar. Let the battery discharge and then see if on recharging it reboots itself.
A wonderful camera.
In June 2012 I questioned why modellers chose to remain uncredited for their painstaking work unlike artists who invariably sign theirs.
An article appeared in the 12th July issue of The (Dundee) Courier magazine about the recent sale of a model of the ‘Charlotte Dundas’ by the Australian auctioneer, Leonard Joel Auctions of South Yarra. Apart from the staggering price what struck me was how well documented the provenance of the model was. Not only were the builders named, but the source of the material was identified too. For me this made a refreshing change that for once the builders gain recognition for their work.
Without this documentation I wonder what it would have fetched. The usual £50 to £100 as a dusty relic no longer loved?
To read more about it follow these links to the Auctioneers website:
As this years strimming season gets into full swing……
I fitted the starter lever last night. It took me about 5 minutes. As I didn’t see the Strimmer with the original lever in place, your notes were very helpful. Thank you so much for solving my husbands problem, as it was he who broke the plastic lever. Kate.
Follow this link to the repair article
One of the delights of my restoration work is opening my ‘inbox’ and reading an unexpected update from a previous client. Just such a thing happened the other Friday;
I expect you’ll recall about two years ago restoring the galleon which was made by my grandfather.
Once it arrived back in Chobham it was kept safely in its box, having first been admired. At the time we were embarking on a kitchen extension which became a protracted project, dogged with difficulties and plagued by problems. Part of the scheme was to block the old exit to a first floor balcony (which was enclosed to become the extension) and my husband designed a feature for the old door space which we hoped would do justice to the galleon. The attached photo shows you its final resting place, which I hope you will feel displays your work well. We had considered covering it with a glass dome but decided it should be seen in its natural glory. Needless to say it’s my job to do the dusting!
I thought you’d like to see where it ended up and hope that you approve.
Read about the original restoration