Confused at Stuart Pricing

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Apr 23, 2012
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Hi, I am picking through the Stuart website looking for a small engine to build and I am confused by the balance of their prices;

Example 1, the S50, 10H / 10V with 3 inch flywheels are all listed at GBP73.50 (no VAT), which is sort of reasonable being similar specs, and the twin cylinder D10 and Score at GBP146.50 is understandable. But then the 7A vertical and No. 8 horizontal engines, being only slightly larger on cylinder and flywheel are GBP199.00, nearly three times the price compared to the similar single cylinder models and twice the price of the twins. They even state that the 7A is suitable for a beginner, just like the S50 and 10V / 10H.

Example 2, the Beam and Half Beam are GBP235.00 while the apparently more simple and smaller No. 9 is GBP302.00. The Victoria, being larger than the No. 9 except in bore is also nearly GBP100.00 less than the No. 9

Am I missing something here? I am not familiar with each of these engines but it seems there are large disparities in prices versus size and complication. Is there something special about the more expensive engines that justifies such an imbalance?

In general, I find the website is very sparse on information and very poor or no photos.

Also, what do they mean when they say (in a few cases) "No materials are included in this kit"? What does "materials" refer to?

Please enlighten me!!
I can not speak for Stuart. But I do know the laws of scaling are often not understood and com into play when counting the cost of material.

what seems like a little bit bigger can be more difference than you think.

For example take an engine of 3/4 and make all parts 1.3333 times bigger. or 1.333^3 makes the engine 2.35 as heavy and takes 2.35 times the material.

Also, what do they mean when they say (in a few cases) "No materials are included in this kit"? What does "materials" refer to?

Most casting kits include the materials to make the small parts of the engine. screws, nuts studs , shaft material material for pistons end caps con rods etc.
The materials sometimes referred to as hardware and bar stock to complete the kit.

Stuart kits are classic I have a 10 H kit and would love to have the 10v. There is lots of info on how to build them .

You may want to consider a simple bar stock engine for your first build.

So Please read the sticky threadss here especially in the about HMEM sub fora.
there are threads to help people get started in this hobby.
Also please post an introduction in the welcome sub fora .Tell us about yourself ,your shop and machines ,your interest in building models and your location.
As Tin mentioned, a small increase in engine size can result in a substantial increase in material required. Just a guess - perhaps some of the price disparity is that the 10H and 10V are probably priced low as they are the most popular Stuart engines most suitable for first time engine builders and as such Stuart has likely recouped the mold manufacturing costs long ago and cranks out hundreds of such castings at a time. The S10 though less popular, will be priced low as it is even simpler than the 10H/10V. the Stuart 9 is rather more substantial engine (in weight and complexity) than the two smaller beam engines.

Stuart refers to "materials" as the bar stock necessary to make all the parts that do not come as castings. Depending on the engine, this can include parts like piston & valve rods, crossheads, slides, connecting & eccentric rods, crankshaft, support columns, steam pipes, cylinder cladding, etc.

Stuart generally refers to "fixings" as the nuts, bolts, screws, studs, ball bearings, piston rings, gland packing.

For the beginner to intermediate engines, Stuart generally includes all the castings, material and fixings to complete the engine. As a cost saving measure for the more advanced engines, Stuart has been moving away from including materials, and in some cases fixings too, with the belief that most people who would be making such engines likely already have an overflowing bin of bar stock, or are well versed in sourcing the bar stock on their own. Depending on the engine and the choice of materials you use, the cost of the bar stock can be as much or more than the cost of the castings. And unless you wish to make your own nuts and bolts, BA nuts and bolts can get rather pricey these days, assuming you can find the sizes you need.

Optionally, you can also purchase things like oil cups, drain cocks, lubricators, air/steam nipples and fittings, paint and oils - none of these items are included as "fixings". For some of the horizontal engines, you can optionally purchase a governor. And for some of the upright engines, you can optionally purchase reversing kits which may or may not be included with the base engine. It has become hard to tell which engines include the reversing kit - just because the photo of the completed engine shows reversing gear does not mean it comes with the engine. the triple includes reversing. The twins have not previously included reversing. None of the un-machined casting kits include any cutters like taps, dies, drill bits or wrenches that you may need.

Hopefully the above helps take some of the mystery out of Stuart's website.
To put those prices into perspective, way back in about 1970 my wife bought me a 10V castings set. It cost 30 pounds, about the same as one-months wages at that time. And now, the price is less than my weekly pension, which makes them effectively one-quarter of the price that they were 45-years ago. Good for you, Stuart of Henley.

Tin, thanks for the reply. I understand how scaling can have a rapid effect but in the smaller sized cases I quoted, the flywheel diameter goes up 0.5 inch, the overall size is the same, and the complexity would seem to be similar but the price jumps by 300%.
And I still don't understand the fact that the Beam and Half Beam being apparently much more complex and more or less identical in size to the No.9 are GBP80 cheaper. In fact the Beams are only GBP36 more to buy than the much smaller and apparently simpler 7A and No. 8. That's why I thought that maybe the relatively expensive examples I picked out may have some super-duper feature that is not mentioned in the descriptions.

rHankey, assuming there are no other factors then your answer regarding pricing disparity makes the most sense to me.
I was confused by the "materials" thing because for some of their models they specifically mention "bar stock" as being not included and they seem to classify "materials" as something different. But your explanation makes good sense, thank you.

Geoff, I wasn't complaining about high cost, just couldn't understand why the apparent disparity in their line up.

The Old Model Company has a really nice description of each of their models with good photos and video. If the Stuart website was more informative and had better photos, I imagine there would be a lot less dumb questions like mine!! The best sources of information seems to be from other people's website and Youtube.
Having worked in marketing in the computer world I can assure you price is not simply based on the weight of material. Many factors apply, and in this case some models that sell well may have very efficient tooling made, making the per piece cost low, but others may only have simple 'one off' kind of patterns which are expensive to mold. Some of the molds may now be getting well worn, making it hard (expensive) to get good castings. Many factors apply, not simply the weight of iron.

I am doing an old ST compound Marine engine now. It came with all the material- simple pieces of rod and some small bits of sheet. I think these were often not worth the trouble- they send you just the amount needed, but if I used my own rod I would have plenty to chuck, etc.

The fasteners are a different story. Although they are the BA screw series they are such finely made and perfect scale that I bought BA taps and dies so I can use them. Getting a kit without these screws would make it hard to do a really fine model. But they count out exactly the right number so be damn careful one bolt doesn't roll under the bench!