The first question I would ask around on is the type and the cost of the boiler you want to do. Copper boilers this size will be extremely costly and could take a very long time if ordered from a professional boilermaker. Steel boiler may be cheaper in materials but professional welding to meet local / national regulations is very costly.

If funds are unlimited please disregard my comments above entirely, but if cost conscious like many of us, the boiler will be a big factor in overall costs.

You may need to have some large parts made on others' larger equipment, ie boiler parts wheels flywheel if they will not fit your Boxford, No problem if you have a friend or friends with such equipment but can get costly if you have to have work done at a commercial machines shop. Not trying to discourage you in any way, just mentioning these things for awareness. Good luck.

Julian,

As Jason says in that size a steel boiler is the only way to go. Andrew must have been waiting for me to pop up!

Depends on your outlook but I don't think the costs are as scary as Jeff portrays. My 6" has cost me North of £10k, couldn't tell you exactly as I have stopped counting. Castings were about 15%, boiler 20 – 25%, rubber tyres 10% all of which were incurred in the first couple of years (been on it nearly 5 now) the rest sundry materials, fastness, cutters etc. I have done a lot of the smaller parts on a hobbymat, myford and mini mill and there are a lot of small bits but there are also some big hits, I am fortunate to also have an Elliot Omnimill and a Harrison L6 as well as access to a Bridgeport, Kearns horizontal borer, large radial arm drill, Holbrook, Edgewick, large Harrison and other assorted machines. The crank shaft, wheels, diff and flywheel were all done by me on large machines as was the cylinder block on the HBM and my Omnimill. I also cut my own gears on the Omnimill. So there haven't been any sub contract machining costs, with only the Boxford you will struggle unless you have access to some bigger kit, even for a 4 1/2" engine. With some creative set ups you will manage some of the bits but not all of them and if you have to pay someone to do them, that could cost as much as the boiler! Also consider the space you need, when mine is a pile of bits there is a lot of them. Don't be put off but certainly if you are going to buy a mill buy a big one! Finally be prepared for the time requirement, mine has absorbed most Saturday's for five years and a fair few evenings and other odd days and I am not finished yet! It is no short term or quick undertaking. However with enthusiasm and tenacity it is eminently do-able and very satisfying. Do remember though that most drawings contain errors so if you are contracting stuff out, make sure you check all the dimensions carefully before placing the job!

Other than that, go for it!

Paul.

Julian, one thing to take into consideration is what you will do with it when you have built it. If you intend to rally it, and take it on the road, then I would suggest a 4" scale of a large original is the minimum to consider. Such an engine will fit into a medium size van for ease of transport. I would look at the 4" Garrett, this was the first TE I built, and I found the drawings the best I have come across. I would confirm you need a steel boiler for an engine of this size. I built mine using a Colchester Bantam, and an Elliot Omnimill. I did have access to bigger machinery for the few larger parts.

I would also be looking to see if there is a ME society in the area with plenty of members interested in road steam, and I would join. Then you can draw on their experience, and if you are lucky they will have a workshop you can use with bigger machinery than you have. I would guarantee that a few of the members will also have larger lathes, and in my experience will be glad to help.

Incidentally I am currently giving my 4" Garrett a make over, and after 21 years of 10 -15 rallies a year the cylinder bore is nicely run in, the worst wear is in the valve links, which will need rebushing and the pivot pins replacing.

Chris Gunn

My Ruston Proctor will just fit into a 6' x4' box trailer which I tow behind my Mazda 6 which can legally tow 750kg unbraked.

The trailer weighs 220kg and the engine 700kg. Loaded up with tools and supplies it is over 1 ton, so I had to upgrade the trailer with a bigger axle and add electric brakes.

Paul.