Has anybody built Beng’s Danni Steam engine.

[Ian S CParticipant @iansc]

Brian, you might think of putting a belt over the flywheel, or maybe just a bigger pulley on the crankshaft, that to a small pulley on the generator should give you plenty of rpm. I find it's a bit of time trying different ratios, and for these pulleys I use 1032/3/16" UNF screws from electrical fittings, these hold the pulley without slipping, but also without marking the shaft. These screws are also OK on flywheels on hot air motors, and probably on small steam engines.

Ian S C

[Pierre KotzeParticipant @pierrekotze18365]

I am a new member and has followed this topic for a while. I completed my "Danni" without any problems on a Taig mini-lathe. It's running in reverse, and the belt pulley is for a project where I need lots of rpm's. Lubrication is a mixture of light machine oil and fine graphite powder.

Pierre

[Neil WyattModerator @neilwyatt]

Very nice, Pierre.

[Brian JohnParticipant @brianjohn93961]

That looks good Pierre. How did you machine the flat on the cylinder ? Did you use a milling vice on your lathe ? Did you have trouble making the control valve ? My taps kept breaking trying to cut an M2 thread in the stainless steel. In the end I made the control valve out of bronze and silver steel. I may have another go at a stainless steel control valve now that I know the engine works.

NOTE : your flywheel looks to be different in that the spokes are curved.

Edited By Brian John on 23/09/2017 02:09:54

[Lawrie BradlyParticipant @lawriebradly72996]

Hi Pierre, I am intrigued as to what your project might be, that needs lots of rpm's. A dentists' drill perhaps? Regards, Lawrie.

[Pierre KotzeParticipant @pierrekotze18365]

Brian,

I attach a photo of how I machined the flat on the cylinder.

Maybe I was lucky when threading the valve stem. I have a 30+ year old set of high quality metric taps and dies and they are tough!

I received the straight spoke flywheel with the Danni kit from Bengs, but later on I ordered the curved spoke flywheel from them. Currently selling for 30 Euro.

Pierre

[Pierre KotzeParticipant @pierrekotze18365]

Lawrie,

I intent to build a small replica of a table saw, using carbon steel cut-off blades 25mm dia.

Pierre

[Lawrie BradlyParticipant @lawriebradly72996]

That sounds like an interesting project Pierre. (I was joking about the steam-powered dentists' drill.) Regards, Lawrie

[Ian S CParticipant @iansc]

I run a mini power hacksaw on either of three of my hot air motors, it's not exactly "high speed" a bit of 10 mm rebar takes about twenty minutes. I usually run the motor at 600 to 900rpm, and the speed reduced to about 100 to 150 stroke per minute. Driven from the 180W electric motor on my Super Adept lathe, it will cut the same bit of steel in less than 5 minutes. Powered by a Stuart Turner S9 the saw cuts at a similar speed to the electric motor power.

Ian S C

[Brian JohnParticipant @brianjohn93961]

I really don't think the small Danni steam engine will be up to cutting anything but hopefully Pierre will prove me wrong. His boiler may have more power than mine and his steam engine was probably better made.

[HopperParticipant @hopper]

Perhaps a Danni-powered cheese slicer?

[Brian JohnParticipant @brianjohn93961]

Cottage cheese perhaps but definitely not Parmesan !

[Pierre KotzeParticipant @pierrekotze18365]

Brian,

This table saw will be a replica like you find in the Mamod category. It is not supposed to cut anything – it will just buzz along like one. I plan to make various small realistic 'toy' tools that can be powered by the Danni.

Pierre

[Brian JohnParticipant @brianjohn93961]

Aha..now I understand. I think the Danni might be powerful enough to run a small dynamo and a light. It depends on how much steam pressure you get from your boiler. What sort of boiler are you using ?

[Lawrie BradlyParticipant @lawriebradly72996]

On the subject of boilers, here is my set up. Seeing it, some people laugh. Why would that be?

[Ian S CParticipant @iansc]

Good set up Lawrie, I was going to do the same, slightly larger pressure cooker, but my sister got down on it before I got a chance.

There was an item in ME, probably in the 1990s of Stuart Turner steam engines being use with a generator as a battery charger for clandestine radios in France during WW2, the boiler was a large army pressure cooker, for transit the motor/generator was packed inside the cooker.

Ian S C

[Lawrie BradlyParticipant @lawriebradly72996]

That's very interesting Ian, about the steam generator for clandestine radio batteries. I googled it and came up with a photo and short description of the ALCO Steam Generator (Stuart/Sirius) – UK 1944. This is the link: http://www.campx.ca/WWIIClandestine.html Another reference said the Australian War Memorial has one. I bought a set of castings for a Stuart 10V engine off eBay a while ago and intend starting on it when I've finished my Danni projects. My set of castings were originally bought in England in 1976. The bloke who bought them never got around to it and after he emigrated to Australia they remained in his wardrobe in country NSW for about 40 years, before he sold them to me. There is a great series of about 30 step by step videos on Youtube by 'Tinker John' on building the 10V. I know I could have bought the castings new from Stuarts, but I rather like the history of this set – all documented with original receipts, etc. As it is, if I mess up any of the castings I might need recourse to Stuarts, but I hope not.

[Pierre KotzeParticipant @pierrekotze18365]

Brian

I don't have a suitable boiler at the moment, so I'm running it on compressed air. She can idle along at 3 psi, or really shake the table at 25 psi. At this higher pressure I cannot stop the crankshaft rotating by pinching it with my fingers.

A couple of things make this engine run strong:

I stuck to the best tolerances I could. Proper alignment of all parts is necessary to eliminate friction. I also used small amounts of gasket sealant on all mating surfaces ( cylinder- and piston valve end caps) and the valve box cover. She will hopefully not blow steam all over the place when I hook her up to a boiler.

Pierre

[Brian JohnParticipant @brianjohn93961]

Pierre ; it sounds like you have made the engine very well however, if you seal everything that well then this can cause water to be trapped in the cylinder both behind and in front of the piston. The engine can lock up after a few minutes of running. I have had this problem with some engines I have built from pre-machined kits. Tapcocks are one solution but there is not much room to install them on this small engine. I have found that running on air can be very different to running on steam.

Of course, a boiler of a different design to mine may give better results ; you will not know until you run it on steam.

[Ian S CParticipant @iansc]

A mate has a very old V10(pre WW2) in his Museum, it actually has 3 steam cocks on the cylinder, one at each end where you would expect, then another in the center of top cylinder cover.

Ian S C

[Brian JohnParticipant @brianjohn93961]

I had to wait a while for my brass plates to arrive from China so that I could build another firebox for the horizontal boiler for Danni #2. Almost finished now… I just have to attach the boiler bands. Some of the brass plates (0.6mm thick) were a little bit bent and buckled when they arrived. As they were sent in a small box, then I assume that this happened during the cutting process. I ordered extras so I was able to put these aside and just use the better flat pieces. I might try 0.8mm plates next time but that could make cutting out the curves for the boiler a bit more difficult.

Is there any way to flatten out brass plates once they become warped ?

 

 

Edited By Brian John on 15/10/2017 08:04:22

[Lawrie BradlyParticipant @lawriebradly72996]

Hi Brian,

Maybe the brass plates could be straightened by tapping them on an anvil, perhaps with a plate between the hammer and 'the work', and 'the work' and the anvil, to prevent damage? (We should all have an anvil, but I've only got a vice I made in Tech' school. It does though, however, provide the necessary flat solid metal surface).

Looking back at Ian's photo of the V10 Stuart engine, I'm reminded of the nexus between restoring motorbikes and steam model making. There are a few bikes in the background of Ian's photo. I've got three bikes (Ariel and BMW) I've restored in my garage and no room now for any more. That's one of the reasons I'm now stuffing about with little steam engines. I am also appreciative of the fact that they are a damn site less expensive to play about with than old bikes

By coincidence, I finally got back today to milling the slots in the conrods of my Danni engines (a single and a twin – effectively three engines), I'm not getting a 'perfect result', but then if you aim at perfection you're bound for disappointment..

Regards, Lawrie.

[Ian S CParticipant @iansc]

My friend Matt has over a dozen bikes as part of his Museum, mostly Honda, but also BSA, and an Indian built Royal Enfield diesel powered bike with a side car, it's that slow that when he took it to a show he displayed it as a stationary engine. Ian S C

[Brian JohnParticipant @brianjohn93961]

I have finally finished Danni #2 steam plant. The housing for the horizontal boiler gave me some problems as I constructed it differently from the first one. It eventually worked out okay and now it runs well. I decided not to paint the boiler with the heat resistant paint on this one as it turned out to be not all that heat resistant on the first boiler !

(Can somebody fix that video link please ? I do not know why that does not work anymore.)

 

 

Edited By Brian John on 21/10/2017 10:07:32

Edited By JasonB on 21/10/2017 10:09:58

[JasonBModerator @jasonb]

Running like a good un

[Author]

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