Author Topic: steam engine with 40 mm bore  (Read 7791 times)

Online Michael S.

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steam engine with 40 mm bore
« on: March 14, 2023, 10:07:25 AM »
Hello everyone,

I want to start a new build report.
A short time ago I was able to buy cast parts for two steam engines. There are parts for a single cylinder and a 2 cylinder machine. Both with a piston of 40.00 mm diameter. and 44.00mm stroke.
I have a blueprint for the one-cylinder machine, but there is no blueprint for the two-cylinder machine.
The design dates back to the 1930s and was offered in a small series by a small machine factory for model builders. I got the castings from a guy who owns the original wooden models and had some cast iron parts made.
I'll start with the single cylinder engine.

Unfortunately, I could not find out much information about the original manufacturer of the castings. His name was Max Dörfel from the Thuringian Forest and he had a mechanical workshop and was perhaps also a dealer for tools and lathes.

Michael

Offline Dave Otto

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Re: steam engine with 40 mm bore
« Reply #1 on: March 14, 2023, 12:25:58 PM »
Looking forward to following along!

Dave

Offline crueby

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Re: steam engine with 40 mm bore
« Reply #2 on: March 14, 2023, 01:52:08 PM »
Looking forward to this build!   :popcorn:

Online Michael S.

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Re: steam engine with 40 mm bore
« Reply #3 on: March 14, 2023, 02:16:50 PM »
The first thing I wanted to do was work on the faces of the base. Unfortunately, my milling machine is too small for the part.
I filed the four feet. But previously prepared with the grinder. There were spots as hard as glass on the little feet that had to be removed first.
The top of the base is already quite flat. There is only a small dent in the middle.
Now the only thing that helps is file, file and file.
(The first year of my apprenticeship also consisted of a lot of filing.)
I don't need a 100% straight surface and by constantly checking with the straight edge I have achieved a good surface.
Including a slowly blackening workshop.

Michael
« Last Edit: March 14, 2023, 02:25:30 PM by Michael S. »

Offline simplyloco

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Re: steam engine with 40 mm bore
« Reply #4 on: March 14, 2023, 02:32:10 PM »
Very nice Michael.
One of our later apprentice jobs was to make a surface plate about that big. There were three of us. The instructor removed three completed plates from his cupboard, and smashed a 1/4" chisel into each of them, and said "Now get on with that, and I want them all to stick together like slip gauges!".
It took a while with chisels, files and scrapers, but we made it in the end...
« Last Edit: March 14, 2023, 06:19:34 PM by simplyloco »
Strong minds discuss ideas, average minds discuss events, weak minds discuss people.” ― Socrates

Online Kim

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Re: steam engine with 40 mm bore
« Reply #5 on: March 14, 2023, 06:09:48 PM »
A new project!  How exciting!  I'll be following along Michael  :popcorn: :popcorn:

Kim

Online john mills

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Re: steam engine with 40 mm bore
« Reply #6 on: March 14, 2023, 07:13:52 PM »
I will be following 
John

Offline Grateful Ted

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Re: steam engine with 40 mm bore
« Reply #7 on: March 15, 2023, 02:35:53 AM »
Very interesting model, love the crankshaft.
Count me in!

Offline Jasonb

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Re: steam engine with 40 mm bore
« Reply #8 on: March 15, 2023, 07:56:30 AM »
It's an unusual design having the two separate extensions to the legs of the "A" frame and I don't think I have ever seen that on a model or full size before and can't see a specific reason why it would have been done that way unless they also offered a different base casting more suited to use in a boat hull that had the bearing housings cast integral to it and the lower height would have been an advantage and then used the same "A" frame for all versions.

The amount of work levelling the top of the box bed casting is a good example of why many full size and model castings have raised areas where any part swill attach. This greatly reduces the amount of machining needed to get a level surface for all the parts to fit to be it back in the day with what they had and now for us.

I will follow along and see how things progress
« Last Edit: March 15, 2023, 08:04:51 AM by Jasonb »

Online Chipswitheverything

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Re: steam engine with 40 mm bore
« Reply #9 on: March 15, 2023, 09:12:22 AM »
Very interesting to see your excellent pictures and, as it comes together, a build write up,  of engines that are entirely different to the familiar ones that we usually see.  Looks like being a nice project.  Dave

Online Michael S.

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Re: steam engine with 40 mm bore
« Reply #10 on: March 15, 2023, 10:05:51 AM »
I also suspect the "A" stand is intended for a marine steam engine. Just as intended for the two-cylinder machine. For the stationary variant, the extension is an emergency solution.
In the blueprint for the single-cylinder machine, the description at the top also says "ship steam engine"!? But that fits better with two-cylinder machines. But there is no blueprint for this. But the "A" stand is the same and perhaps the one-sided step on the stand is intended for a shaft of rotation reversal. An oil pump could be mounted on it for the single-cylinder machine. I will do that there. I think the original design plan was the marine steam engine.

Michael

Offline Jasonb

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Re: steam engine with 40 mm bore
« Reply #11 on: March 15, 2023, 10:47:56 AM »
Certainly an unusual base if it was intended for use in a ship as the propshaft would be very high and the spoked flywheel is not right either.

I suspect that they may have originally done it as one for a boat and then just used the same castings for this model, they would better suit a base like I have shown below. Having said that I had not seen the style beforeI remembered the model "Anna" does actually have a short A frame much like yours http://www.ateliermb.ch/shops/gussteile/ch/contents/de/d37.html

Yes I think that block on the leg would have been used to mount a pivot for a shaft that activated reversing valve gear at each end of the engine, a boiler feed pump would have been a more usual fitment for use in a boat than a mechanical oiler.

Online Michael S.

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Re: steam engine with 40 mm bore
« Reply #12 on: March 15, 2023, 12:58:03 PM »
Yes, a feed pump is also possible.
Nice that you found the website of the Swiss manufacturer of these machines. I've seen the smaller model in bronze at an exhibition before. I didn't know there were cast parts for it. On the website they write that the model was built after a German model. This machine was also available from Max Dörfel in a different version with a bore of about 25 mm.
Thanks for the hint.
Since the machine will definitely be operated with steam when it is finished, I am thinking about a feed pump.

Michael

Online Michael S.

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Re: steam engine with 40 mm bore
« Reply #13 on: March 15, 2023, 07:41:50 PM »
The first thing I did was the crankshaft bearings. The lower parts were milled in parallel and brought to the same length. The caps were also milled and soldered with soft solder.
The hole for the bronze bearings was then drilled in the milling machine.
The outer contours were machined on the lathe.
The rest was again a job for the file.
I am very satisfied and am waiting for material for the crankshaft and bronze for the bearings. Then I can align and attach both bearings to the base.

Greetings Michael

Offline crueby

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Re: steam engine with 40 mm bore
« Reply #14 on: March 15, 2023, 08:02:13 PM »
Great progress!    :popcorn: :popcorn:

 

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