Hi Beardy Mike, Stuart Models and Mac Models Mac Models might have something you are interested in, or maybe Reeves 2000.

Regards Nick.

Hemingway does a few steam engine designs, which can be bought as fairly complete kits with build notes, which can be useful. Perhaps not the very simplest projects but attractive models.

Nothing exotic needed for the Clarkson

PGMS or silver steel for crankshaft

Stainless 303 for piston and valve rods

Bit of brass or bronze for the glands for those two rods

ditto for valve and nut & cross head

0.5mm aluminium sheet for cladding if you want to fit it.

Steel round for conrod.

Although I am not keen of “bills of materials” I’ll knock one out later or tomorrow. This will give you an idea, items with their name highlighted are from barstock. I don’t tend to buy hex and square, you can mill that from round bar used for other parts so less sections to buy.

The Blackgates catalogue photos do not do their engines justice, this is what you get in the casting set (plus the eccentric strap)

PM about to be Sent

Always check the flywheel sizes!

There are lots of great designs that are a bit larger and less fiddly with 8″ flywheels, but you can’t turn the flywheel on a 3.5″ centre height lathe like a mini-lathe.

Neil

Converting fractional inches to decimals is a very easy process that only takes a few simple key strokes on any or even with the most basic of calculators with a method that many don’t seem to know about. Fractional inches have an upper number (the numerator) and a lower number, (the denominator) ANY fractional inch dimension no matter what it is can be converted to exact decimal inches easily. Take the top number whatever it might be and divide it by the bottom number. Example 1/4″, 1 divided by 4 = .25″ With the decimal equivalent known, it’s then easy to convert that to a metric dimension if that’s what you want since the imperial inch is actually based on it being exactly 25.4 mm to the inch. I’ll use that 1/4″ or .25″ as another example, .25 x 25.4 = 6.35 mm.

Or fractional inches to exact metric almost instantly with a few less key strokes, that same 1/4″, 1 divided by 4 x 25.4 = 6.35 mm. I have a wall chart with the common fractions and there decimal equivalents, for any I don’t already have memorized, I usually won’t walk the few steps to even check it since that calculator method is faster. And the most used tool in my own shop is a calculator, so it’s always handy. Imperial or metric is just a mathematical concept and one verses the other really isn’t any better or worse than the other. Metric is easier without a calculator, threads and there tap drill sizes are certainly easier with metric, but that’s about it for what we might be doing. For myself I was taught in school and can still visualize much better in imperial, so I just use that as my measurement of choice. But I can sympathize with those that have only been taught metric. Imperial fractions probably do seem a bit confusing, in reality it’s all pretty basic if you know that easy conversion method.

A small steam engine is the obvious go to to build, but I would suggest that a Weir type steam pump is a better choice.

Why? Smaller, simpler, only needs a tiny boiler to run, no flywheel, does something, and absolutely fascinating to watch. I bought my castings from Kennions, but there are other suppliers.

OP has a CNC mill so that can make a pretty large flywheel, not to mention using the lathe as a mill to machine a flywheel. the latter could make a beginners article for MEW.

On 7 October 2024 at 07:58 Pete Said:

Converting fractional inches to decimals is a very easy process that only takes a few simple key strokes on any or even with the most basic of calculators with a method that many don’t seem to know about.

True, but beware.  The problem is the process is tedious and a big plan may require lots of conversions.   The combination makes numeric conversions error prone.   Unfortunately double checking is even more tedious, so annoying mistakes still slip through galore.   It helps to be numerate, to have practised mental arithmetic, and knowing the common conversions off by heart makes it easier to spot sillies.

 

…. Imperial or metric is just a mathematical concept and one verses the other really isn’t any better or worse than the other.

Not so!  The problem with Imperial is it’s riddled with internal conversions.  Imperial units were derived in isolation, when measuring the weight of spuds hand no obvious connection with measuring length or time.  And before electricity, of which it has no concept!

In a home workshop, there’s rarely any need to calculate using derived units, so all seems well.   But Imperial behaves badly when engineering calls for grown-up maths because Imperial requires multiple internal conversions.   Look at this simple example:

Applying the formula is easy enough and the answer is 10,800 lb. per sq.in.  But hang on, my question to the friends of Imperial is, what’s the 6 in the formula for, and where does it come from?

It’s a ‘magic number’ resulting from mixed units.  The Imperial system being internally incoherent means that it’s littered with them, and they turn anything other than basic maths into a minefield. They’re an extra complication making more work and causing mistakes, definitely not a good thing.    In contrast, Metric was designed to eliminate ‘magic numbers’ and other faults.  Much simpler, and far better suited to maths based engineering.

Fortunately for Imperial fans, Model Engineering rarely calls for the more advanced calculations that expose the systems shortcomings.   Advanced calculation is unlikely to be needed unless a ME is doing design rather than following an existing plan.

As all conversions are bad, converting Imperial plans into Metric, or vice versa, is risky.  Small projects aren’t too awful, but converting a big one quickly turns nasty because bored people make mistakes.  Well I do!

If it has to be done, a slide rule is surprisingly effective because the numbers don’t have to be typed in.

Dave

Why go for a kit with castings, how abut one from plans. Like some of these by Jerry Howell