The number 173.

[Michael S.]

Hello,

I would like to tell you about a model steam engine that I restored two years ago. When I bought it, it wasn't finished yet. The first builder may have started building the model between 1920-1930. It is a model from the 1925 Wilhelm Bischoff catalog from Dresden - Germany. It is called number 173 with a 30 mm bore and 50 mm stroke. There are still some parts missing and there are also some bugs on the machine.
I disassembled it and we're good to go.

Michael

[Admiral_dk]

The old part you got here looks to be good shape for their age 
So I guess that it is mostly a question of making the missing bits + testing that the Old parts are made to the correct measurements ...?

Will follow this with interest 

Per

[Michael S.]

Since all parts were individual, the base was measured and a wooden model was built. A friend from university made a cast in aluminum.
I would like to rebuild the model again later.

Michael

[Jo]

Nice little engine   

A quick translation to save others the time:

30mm bore, 50mm throw. Made from the parts of set 205 on page 29, Equipped with bronze bearing shells, regulator, throttle valve, feed pump, large hollow cast foundation and 2 condensate bowls, as well as oilers, in a varnished and nickel-plated design, output approx 1/15 HP

Actually it not that little 

Jo

[Michael S.]

yes Per, the controller, eccentric and control valve, water pump and a few other useful things are missing.

Michael

[Michael S.]

hello Jo, thanks for the translation. I didn't even think about that when I chose the picture.

Michael

[Michael S.]

The main flaw on the model was the crooked cylinder on the frame. The builder himself had problems with it. He tried twice!
I changed the holes from M 5 to M 6 and sealed them with bolts and glue. Then smoothed in the lathe.
That worked quite well.

[propforward]

You are doing some really good work there - that is a fine model and once you have corrected it and made the missing parts I think it is going to be a super engine. Very nice save on the cylinder!

[Michael S.]

Now the new holes should come to the right place. I used the front cover of the cylinder as a template. It is held in position with short screws on the frame. The cylinder is clamped to the lid with Teflon tape and can be aligned and marked with the right angle.
Now the cylinder with cover can be carefully removed. The holes are marked with additional clamps. Then you can drill and tap the thread. This is not the super accurate method, but it worked quite well.

Michael

[Zephyrin]

these beautiful castings needed indeed this expert work of restoration...
30 mm and 50mm stroke, that is pretty large for a model !
An odd point is that I don't see any steam port or passage in the extremities of the cylinder, are they cast in and open deeper into the cylinder ?

an opening in the middle of the cylinder is visible...an oiler or some sort of uniflow port ?

[Michael S.]

Hello Zephyrin,
the cylinder has the steam passages in the casting. There are holes for condensate valves on the bottom left and right of the cylinder. Even in the middle was a hole. But I locked it. In the top center is a hole for an oil connection. There's an oil jar on there.

Michael

[Michael S.]

The valve chest cover is finished and now has a lid. That was missing. The cylinder is covered with sheet brass. The piston was a very good fit and I didn't need to do anything to it.

Greetings Michael

[Admiral_dk]

Nice progress - do you plan to paint it later ?

Per

[Michael S.]

Hello Per, yes the castings were all painted. (it's been a year since it was built)
There is two coats of primer and then two coats of paint. Bischoff's steam engines were always chocolate brown. With decorative stripes.

Michael

[Michael S.]

I painted the machine as I once saw it on a finished original machine. I need more practice for the decorative strips. The black stripe was made by taping and the orange line free hand. A little detention made painting the tiles. An aluminum plate was scratched and then painted. The control valve is made and a new eccentric ring.

Michael

[Michael S.]

Hi, everyone,
the regulator is still missing on the steam engine. I got myself a cast of an original part. Unfortunately, it was cast zinc and broke very quickly. I made a new cast part from brass parts by soldering them with silver solder. It ended up looking better than the broken part.

Michael

[crueby]

That came out terrific!!   

[Michael S.]

Since there are always oil stains on the tablecloth at model steam engine exhibitions, I wanted to attach an oil separator to the exhaust pipe. An example of this can be found in old books about steam engines. There was a picture for an exhaust steam oil separator for exhaust steam engines.
I installed a metal strainer inside the pot, which drains the oil. That worked well. However, only tested in operation with compressed air.

Michael

[Kim]

Hi, everyone,
the regulator is still missing on the steam engine. I got myself a cast of an original part. Unfortunately, it was cast zinc and broke very quickly. I made a new cast part from brass parts by soldering them with silver solder. It ended up looking better than the broken part.

Michael

I'll say!  That part looks beautiful!  WAY better than the casting you had!

And the oil separator looks fantastic too!  You do excellent work, Michael! 

Kim

[Michael S.]

Hi,

and thank you for your compliments.
The machine is now ready. With steam pipe, valves and also the condensate separator in the supply steam line.

[Michael S.]

a video:

<a href="https://www.youtube.com/watch?v=bEcXgPjWhuY" target="_blank">http://www.youtube.com/watch?v=bEcXgPjWhuY</a>

[Admiral_dk]

A great runner and it looks amazing - you should be proud       

Per

[derekwarner]

Michael.......it is good to see the substantial width of the brass eccentric band over the steel eccentric it self [for the water pump on the axis of the crankshaft]

Pumps on many engines when built to scale have eccentric bands of a width that does not support the same dimensional relationship between diameters

The result of this is the band tends to float or rock off axis when taking up the line of least resistance between the clearances the two parts

Derek   

[Michael S.]

Hello Derek,
since I got a bit lazy with the restoration at the end, the brass eccentric ring is not divided. I was thinking of making the ring a little wider as an eccentric for a control valve.
The ring is pushed onto one side and screwed to a cover.

Michael