Last year I picked up some drawings and parts for the GWR ‘Firefly’ by Martin Evans in 5” gauge. I have spent the last few months working through the drawings and the more I worked on the loco the more I was not happy with the slide bar brackets! In picking up the plans from the previous owner I also purchased at the same time as the drawings some semi-finished parts the owner had already purchased and or made for the model including wheels and some parts reasonably cut from MS plate, these included the slide bar brackets. Just cut from 3mm MS the slide bar brackets gave no feeling at all of the real thing, they looks very plain and flat with no fillets or cast edges as seen of the original full size castings. There was only so much I could do with a file and did not want to use car filler!

So where to start? I could not find any commercially available castings for these slide bar brackets so other than building out the mild steel by adding fillets and rounded edges in some way I was a little lost. Following speaking to another model engineer friend and ex-colleague who lives and works in Cornwall who builds beautiful steam powered model boats I was told about a young graduate engineer neighbour of his who he has used to make small castings in both ferrous and non-ferrous metals from drawings supplied to him.

Let me start by explaining that I have spent my working life in medicine and other than model engineering have no knowledge of commercial or industrial processes, however when I was at school I did learn that a ‘pattern’ of some form is required to successfully make a casting. With this knowledge I assumed that the cost of making my brackets would outweigh the entire cost of my small workshop! Following thanking my friend for his advice I put the ideas of improving my slide bar brackets to bed and considered turning both truck and main wheels to size.

Again though when I looked the brackets and how plain and boring they looked they sent a chill through me as they looked so out of place on what was a nicely proportioned loco. So retrieving the email my friend had sent me with the young chaps details on it I decided to drop said young engineer an email with what I wanted in the form of a pic of the loco and an explanation of what I wanted. Expecting the young chap to laugh at my ignorance and or quote me a ridiculous price for the pair I scuttled back to my work-bench and carried on with the wheels which machined well and were completed the same day.

To my surprise the following morning I had an email from ‘Sam’ who stated that the slide bar brackets would not be a problem at all and that I was to send him the relevant drawings so he could give me an accurate price for the pair! Following his receipt of the plans he said this would be a simple job and quoted me far less than I was expecting! Following sorting out the financials the items as seen in the attached image turned up securely wrapped in bubble-wrap in a box. They were perfect n every way. In fact I spent at least 1 hour measuring them and comparing to both the drawing and images of the real thing. All I need to do was drill and file off the casting evidance.

Suspecting this to be some form of which-craft or wizardry, I could not resist a call to him to ask him how this was achieved so cheaply, so with hesitance I picked up the phone and called him. I expected him to not disclose his practice or methods for reasons of industrial espionage or wichcraft secrecy but he was quite open and told me how it all works these days, laughter in his voice! The steps are as follows:

1. Receipt of drawings, pictures and dimensions in email or printed form.
2. The use of 3D CAD to turn the above data into a computer file of the object or part.
3. Use this file to make a 3D print of the item, it is this that forms the pattern. This was the whichcraft part, or so I thought!
4. Use a burn-out process which vaporises the 3D print and replaces with metal…further whichcraft!
5. Send parts to customer.

Sam did laugh at my ignorance to this relatively cheap process commonly used all over the world. Apparently it is used routinely now for many aspects of model engineering and commercial processes. In fact he has given up a career in a large company making jet planes to run this as a business which I understand is doing incredibly well. He employs 2 people (wizards) who spend all their days making these computer files. A further 2 to make these files into metal objects (including cast iron cylinders for 7.25 locos, iron wheels up to 13” in diameter and a raft of other cleaver stuff) and has many boxes going all over the UK, Europe and the USA every day! I was truly amazed by this so wanted to share this process with you all. I am happy to share exactly what I spent in a private email but putting it into perspective, the truck wheels for 1 truck, cost me more!

I hope this knowledge helps some of you that are not already using this amazing process.

Hi Phil,>>

I am sure he has a web-site but I am not a great mover on the internet. I just used his email which is:>>

[email protected]>>

He always responded within 24hrs maximum.>>

I hope he is of help to you he is a really knowledgeable your fellow.>>

Cheers.>>

That is quite incredible, I had no idea that was how my brackets were achieved.
It does however beg the question, given such a complex preparation and process, how were my parts so cheaply made? I cant imagine he made hundreds?