I have a feeling that skinny flywheel is meant to be mounted inboard and fit in the slotted base. That way a take off pulley where the flywheel is now situated would be better supported should you want to drive something with it.

As Mike says bit of a homebrew rather than a recognised design

I don't like the use of slotted screws where they should be studs and nuts

Roy

Of all the points made about the engines construction has any one noticed the eccentric strap which seems to be made from a hexagon nut and not split, so is the sheave in two pieces ?

I like that engine it's different.

Mike.

Jason, Now that I have looked closer I think you are right saves having to split the strap.

Mike.

"Folk art".. Yes, it could well be. None the worse for that, though. This engine might raise eyebrows with its slotted screws and ball-races, but it's a lovely object in its own right.

I know one model-engineer who built a beautiful (3"?) scale Allchin traction-engine, some of it while a diving officer on a RN mine-sweeper, where he obtained the Chief Engineer's permission to use the " tiffys' " workshop in his off-watch hours. He said that if the ship had been sent into action, his engine parts would have had to gone overboard along with the tinned food and the Captain's bicycle.

I once owned a curious little hand-rotated lathe made almost all in brass, and while not very practical for serious work it was intriguing. I'd found it in a second-hand shop, its history unknown. I wonder if that had been a "bunny".

Quite a lot of high-quality tools in circulation were apprentices' training-pieces, too, and sometimes bear the name or initials of their makers, and year of manufacture,, stamped on them.

The 'Mill Engine' design has been around a long time: it's very similar to the 1901 Thompstone Engine Jason is reinvigorating in ME at the moment. (Part 1 is in 4662.) Pretty much the same layout as Stewart Hart's PottyMill, and one of my old text-books describes a full-size engine of the same type. A sort of small simplified mill engine, no reverse, or condenser, slide valve driven by an eccentric, only a couple of HP, plain build, and presumably intended for a small enterprise mixing dough, making butter, driving a laundry or whatever. I believe the type was very common before electric motors took over, and they make good model – not too difficult in basic form for beginners, castings or fabricated, and can be made more elaborate if required. For example the PottyMill's plain Aluminium cylinder is mounted on a block, whereas Jason's Thompstone has turned brass feet inset into a Bronze cylinder with tasty decorative bands.

The polish and fine finish suggest the engine was made by someone who had plenty of spare time. The absence of spokes suggest he or she had access to a lathe, but not a milling machine, and perhaps decided to tackle them later. I agree the flywheel should be in the slot, which suggests the engine has been assembled incorrectly. Possibly someone made it, got it into running condition, and then passed the engine on to a new owner who beautified it, but didn't have the facilities to cut spokes, quite understand the flywheel, or realise the slotted-screws were temporary.

My first PottyMill is rough because I built it to exercise my weak machining skills: it wasn't intended for show, and the result is purely functional with many unfixed blemishes. Maybe when I'm dead it will be refurbished and sold in a glass case as an attractive antique, claimed to have been handmade by James Watt in 1760…

Dave