Opposed-Piston Engine Project - The Steam Version

A special section just for steam engines and boilers, as without these you may as well fit a sail.
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Ramón
Warming the Engine
Warming the Engine
Posts: 82
Joined: Mon Oct 26, 2015 2:32 pm
Boat Name: No Boat Yet
Location: Rostock, Germany, Baltic Sea

Re: Opposed Piston Engine Project - The Steam Version

Post by Ramón » Mon Jun 03, 2019 11:24 pm

Thank you for your answer.

I quess it really shows up eventually if you buy cheap tools. As a student, I was only able to buy a relatively cheap drill press, whose drill table bends down under very little pressure. Now, I just use a short length of a very big suspender as a table and it works better (plus the periodical shifting of the work piece that is)

Now, my most urgent goal is to replace the electric motor of the lathe since there was no way to make the washing machine motor run fast even without load - even after trying every possibility to connect the 5 cables of that motor to the 2 power cables. Gee I didn't know it was so difficult to get a good electric motor. But now I ordered one coming next week. And THEN it gets interesting using the lathe. Before I turn all the pieces neccessary, I will upload all the pieces the core of the engine will be machined from. After I build it up, I will do a second round ordering all the metal for the valve mechanism.

Liberty ships had been built faster:) but at least the project grows.
User avatar
Ramón
Warming the Engine
Warming the Engine
Posts: 82
Joined: Mon Oct 26, 2015 2:32 pm
Boat Name: No Boat Yet
Location: Rostock, Germany, Baltic Sea

Re: Opposed Piston Engine Project - The Steam Version

Post by Ramón » Sun Jun 16, 2019 6:06 pm

To show now what I did and what I didn't do yet: The last piece of metal for the core engine arrived friday. As I explained, I split the building process into two stages:
  • The core of the engine: crank cases, cylinder, intake-& exhaust register
  • The valve train: timing belt drive (probably), the cam axis, the centrifugal governor, the mount for the rotary encoder, the valve block
The point in splitting the task is the highly experimental nature of the project. As you might have noticed, I reconsider my detail choices occasionally after more ideas or input convince me for another approach.

As I already promised TahoeSteam a long time ago ;) , I now show you all a photo of all the pieces I need for the first building step:

Image

I arranged everything in an appealing pattern:
  • The crankshafts both have open ball bearings, which will be isolated by simmer rings on the outer ends. I want to have the lubrication concept as simple and effective as possible. That's why I designed the ball bearings between the crank webs and the simmer rings. Thus, they will be lubricated by the oil inside the crankcase.
  • The 2 small locking assemblies will attach the gear, whose task is to synchronize the 2 crankshafts. I abandoned the idea to link up the crankshafts with a bicycle chain and sprockets, as it is said to be a loud option (older car engines seemed to have a timing chain.)
  • The cylinder will consist of a piece of 303 steel, as does in the uniflow steam engine of a friend of DetroiTug (viewtopic.php?f=8&t=567). I was intrigued by the above-mentioned material pairing and want to try it out myself. The cylinder needs the following adjustments: 2 identical pieces of an exact length needs to be turned. The inner diameter needs to be turned on both pieces. The exhaust- & intake ports need to be milled.
  • The 2 crankcases will consist of all the pieces with the dark skin from the steel works still on. Things, which need to be done: The pieces need some more grinding to be done. After that, each pair of bearing blocks need the seats for the bearings and simmer rings turned. After that, 2 of them will be welded with one of the U-shapes in between to create the 4 of the crankcases. 2 of the 4 welded parts then need to be turned a last time down to a specific depth to receive the cylinder. Afther that, I will fine-tune the cylinder length.
  • The large block of silverish metal with the blue foil on it is the piece of AlMg4.5 Aluminium for the steam intake and outlets. Things, that need to be done: 3 relatively square pieces need to be cut. Each of them need to be sawn in half and bolted back together. Then, each one of these need the outer diameter of the cylinder turned out and the channels milled on the lathe. Then, they just need some threaded holes around the channels to bolt the intake/exhaust registers to them.
I still just need piston pins and needle bearings for the pins, as I accidentally ordered 2 piston packages devoid of pins and bearings. And of course it is near impossible to get piston pins in that size without the pistons. But let's see.

Until now, I've been prevented to reach my goal by this:

Image

This is a mediocre picture of the headstock and cross slide of my home built lathe. It is off topic, but maybe someone might be interested in it: Some shipyard worker must have built it and I found it in a dusty, old 6-storey store house with an antique's trader in it. I immediately fell in love with the old DIY work. I couldn't pass, knowing it might one day be scrapped. Only the headatock was extremely weak and worn. Now it got a headstock welded together with 20mm(3/4inch) steel plates. The industrial bearings hold a 2 inch spindle. It is way oversized, but once it is finished, it will be a very sturdy lathe.

What I am still thinking about is some considerations about the lubrication and the addition of an oil drain plug and a screw to fill it up(which might get a small 2mm rod brazed on for oil checks. I won't realize filtering and water removal on the single cylinder test engine. Only an oil pump needs to be added to get to the top crank case, while a small connection down to the lower crankcase will provide for the back flow. But I just will use an electric pump for the first tests. The goal will be a mechanical oil pump driven by either the camshaft or another auxiliary shaft for all the pumps needed.
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