How long to build?

Great answers guys. Thanks I enjoyed reading those. Good advice.

Just out of interest, does everybody buy castings, e.g for cylinders, or machine them from the solid? Could that save you a bit of cash in exchange for time?

I machined my 3 1/2" Evening Star cylinders from solid, casting and material set from dealer nearly £300, I haven't spent that on all the materials I have bought so far and have a reasonable range. It also gives you good machining practice and workshop practice in figuring out the best process so you can hold the part. Castings can be awkward to hold if you have limited experience.

Find a good local metal supplier and buy lengths that fit in the car rather than just the piece you want. I found a supplier who has lots of offcuts and I mostly buy them, the odd piece I have to get cut if i can't find anything. Sometimes you only get charged for the expensive bits, the others are treated as scrap.

I bought castings for most of my items. Even with the core holes my cylinder casting weighs 29kg. I suspect it would be difficult to buy a big enough lump of cast iron or steel. And I wouldn't like to have to remove the suplus material even on my industrial machine tools. Likewise the final drive gears are 15" diameter so not really practical without a casting. For smaller items like the bevel gears in the differential I used extruded cast iron stock. Even then I ended up with 70kg of cast iron swarf.

Andrew

My daughter made me watch a brief 'TED' video yesterday.

It was very relevant to this discussion. It pointed out that it was discovered that LINUX was spending more time prioritising 'threads' (tasks) than doing them when it got busy, partly because the time to sort them increases as the square of the number of tasks. By changing to a system of classifying the tasks into a small number of groups and servicing the groups without repeated sorting achieved a major speed increase.

The same is true of many tasks in life (checking your email inbox was the example) and making a complex model is a good example. It's very easy to spend lots of time planning a job, deciding the best order to make things in etc. etc.

Now obviously some parts have to be made to suit others, but in general if you want to make progress just tackle the first job that comes to hand for which you have the parts, materials and tools to hand. It's easy (and I'm a prime example of this) to have a whole project stall waiting for some special part or inspiration when I could be getting on with some other aspect of it.

So when you are in the workshop with half an hour or an hour to spare, don't sit there wondering the best way to set up a big complex job, just get one of the little ones out of the way.

Now, I just have to put my own advice into practice.

Neil

I'm probably jumping ahead of myself as I'm still latheless, but It's good to know that machining from stock is an option. As for spending time on jobs, I think I'm fairly good at that. I try to do something every time I go in my work room. I could have bought a set of laser cut ribs for my Vic Smeed Tomboy last night, but soon whizzed 20 off in 10 minutes. I often find thought that with building a complete project, in my case a model aircraft, the old 80% done, 80% still to do, comes into it. Its the little finishing bits that take the time, and make all the difference. Covering with tissue especially. A bad covering can make even the best build look like a sack o' cack. I would guess the same would go with the final coat of paint on a loco.

When I started my Rob Roy in 1979 I thought it would be interesting to see how long I took to build it, so I religiously recorded the time each time I went into my workshop and again when I left. After about 50 hours I got fed up with that when I came across a mains powered hours run meter. Great I thought, just turn on the power to it when I start work and switch off when I finish. Course you can guess what happened, inevitably forgot to switch it on or even more annoyingly switch it off. In five months time that will be forty years and it's still not quite finished.

However, in my defence I have nearly finished building a 3 1/2" Spencer and constructed a garden railway with all the associated infrastructure that goes with it and of course all those other annoying interruptions that life continues to throw at you.

Phil

Some concepts from Software Engineering may be relevant. First came the idea of 'Design Patterns', which outline good ways of solutioneering with a proven track record - 'best practice'. It was then realised that there are also 'Anti-patterns', that is ways of doing things, usually common sense, that have negative outcomes.

Neil's example is 'Paralysis by Analysis', where spending too much time planning and worrying about details stops all progress. But it doesn't mean planning is a bad thing because there are many other anti-patterns like over-engineering and gold-plating.

Don't put the Cart Before the Horse in your Bicycle Shed because you might end up with a Big Ball of Mud. In this world Worse is Better.

Dave

PS Re RevStew's 'how long does it take' question. Technology sometimes bites back. I mounted a vice on my milling table this afternoon. Easy enough except the vice is set an exact right angle to the head by tapping it into alignment with a mallet and checking the result with a DTI. Normally takes me 5-10 minutes to zero in. Today, 40 minutes of industrial language and it's still not spot on...

That's the theme of the book that accompanies the video...

Neil

I've taken a guess at between 2 and 7 years to finish my 3.5 gauge loco, but thats because its a complex one for a beginner, my free time varies as my other hobbies are seasonal (rallying for example) and I've no idea how I'm going to cope or how often I'm going to get frustrated and walk away for a fortnight!

We are sticking with 16mm scale for the moment as there are plenty of designs intended to be built without any castings (see here for a couple **LINK** . That way any failures only cost us the barstock and time. A paperweight made from a poorly soldered 16mm boiler is a lot cheaper than a doorstop from a 5" gauge one too.

There are often incomplete projects on a certain auction site which are a cheap source of castings. We have picked up a couple ready for when we are more confident not to do damage, each a set of wheels and frames and a near complete casting set (with bronze cylinders) for less than the new price of a set of cast iron cylinder castings - even if we threw away the completed parts we would be in profit. Buying ahead can save a fortune, there is more than enough to see my time out in the queue already, but this has also given us the chance to get cheap drawing sets and build manuals tucked away ready.

Brian

If I ever had any ideas about building a loco, this post puts paid to it !!!

After 25 years,how the hell do you remember what it was that you started out to build ?

My span is about 2 days,and not always that !!

Good grief, that's what I call staying power, if it takes me more than a couple of minutes I get niggled and if it reaches 5 minutes I lose interest and go and do something else. What sort of accuracy are you aiming for? I'm happy with one division (0.01mm) on the DTI over 150mm for most normal work.

Andrew

I was strongly considering the Ayesha. I have no pretensions to finishing it inside a decade, and it would be a project to be mostly done at a model engineering club, under a certain amount of supervision I hope, perhaps with smaller tasks being done at home in between. A kind of 'We've done this tonight, but do this little bit at home and see how you get on. bring it back next week' sort of deal is what I would love to have happen!

In my model aircraft building hobby, I've never been shy of scrapping a sometimes nearly completed model, just because it's not up to the standard I have in my head. I used to be ruthless, but then I managed to buy a few free flight models that had been built by some of the real big guns in the hobby, and it was very enlightening. It was one of the best things I did to improve my own building. I could then look and see what the 'expert's had done, and to be honest, it wasn't all that! I wasn't as far off as I thought. But then that was just the building, those guys can fly, pick thermals, and compete too...a different game altogether...

Stew.

Nothing special, less demanding than you - 0.01mm over 90mm. Set-up conventional with the vice initially aligned roughly with a set-square:

I'm wondering if the problem is to do with the size of the studs and washers?

The studs are close fit to the slot in the vice, and the 'washer' is more like a thick spacer. Possibly the stud tilts when the vice is tapped & wedges. The adjustment problem was the DTI would move as expected up to a point and then misbehave, forcing me to start again.

All suggestions welcome!

Dave

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Not exactly sure what's going-on there, Dave ... but there's a nasty burr on the edge of that slot.

I would spot-face the casting, and make some larger diameter [thick and flat] washers ... with a  D shape if necessary.

MichaelG.

Edited By Michael Gilligan on 21/08/2018 20:29:16

I'll set up my vice tomorrow and take some pictures of the sequence.

Andrew

nip one side down to give a bit of friction and leave the other slack. Then it will rotate around the first. I normally get mine within a couple of minutes, but there agin 0.01 mm is 4 tenths, do you really need it that good?