Mount Trapezium

[redhouseluv]

I'm moving onto something a bit more sedate compared to high speed marine engines and a bit different to the Stuart engines which I'm very partial to!

It's the Anthony Mount Trapezium Engine; it has an interesting movement and I found a couple of images of a completed engine online (surprisingly few available). I bought the castings before implementing my rule of not purchasing partially built casting kits, but let's see how things pan out....I have the old Engineering in Miniature copies which cover this build so hopefully they will help

I made a start today by removing the deep milling marks on the Omega shaped engine supports and machining them to size; they are aluminium as are a few of the castings. Are there any tips for machining, tapping and other processes when using Ali, it's not something I've had experience with?

Finally, if someone has built one of these, please let me know, always good to hear about the 'gotchas' 

[crueby]

Neat looking engine!  Quick search found a reference that "The model was designed by Anthony Mount in 1:12 scale and serialised in Engineering In Miniature from July 1997 to February 1998."  A few of the issues with the article can be found here:

https://archive.org/details/engineering-in-minature-july-1997
https://archive.org/details/engineering-in-miniature-september-1997-vol-19-no-3
https://archive.org/details/engineering-in-miniature-october-1997-vol-19-no-4

Not sure if that engine was included in either of the Anthony Mount books by Tee Publishing?

[Jasonb]

Not one of his that you see very often so interested to see how it turns out. Not in either of his books.Was it built to imperial or metric measurements as he did do some engines in dual dimensions and the later ones just in metric?

As for aluminium, you can turn, mill and drill with higher spindle speeds than you would for steel or iron. Sharp tools if you us einserts then get some **GT ones and if you need any new milling cutters than the ones made for aluminium and other non ferrous metals are worth getting not least as theit polished surface helps prevent aluminium sticking to the cutting edges. Also that can be helped a lot with a little cutting lubricant, I use paraffin but WD40 also works or any other very light oil.

[redhouseluv]

The drawings have both Imperial and Metric on them - thank goodness as I'm very limited on metric and really don't fancy buying another whole set of tooling!

Thanks for the advice on machining Ali, I remember having problems when machining gun metal which is also softer.

I've read the first volume of EIM and apparently the engine is attributed to this splendid looking German gentleman Professor Franz Reuleaux who is famed for his diagrams and kinematics?

https://en.wikipedia.org/wiki/Franz_Reuleaux

some of his mechanisms are fascinating and would make great builds!

https://www.engineering.cornell.edu/mae/reuleaux-collection/

[Michael S.]

Hello Sanjay,

These steam engines are very interesting, and I'm excited to see your progress.

There are a few illustrations of these "hanger steam engines"  ,   In German: "Bügel Dampfmaschine"  ,  in old books.

Michael

[redhouseluv]

Thanks for the information Michael, I didn't know there was a category of engine called 'Hanger steam engines'. The name makes sense looking at both the diagram and photo.

There's a few non-cast pieces to make which look interesting, especially the 'hangers'. As the build log states, start from the bottom and work upwards, which is what I intend to do

I found a solitary video online of a completed one running;

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

[Jasonb]

There are a couple of models of the Egell's one that I have seen on German sites, video on the second page

http://www.eckartkercher.de/index_seiten/egells.htm

[redhouseluv]

An ironing machine? If so that's the best looking and most complex iron I'm ever likely set eyes on unless 'ironing' means something else in this context?

What a truly beautiful piece of engineering; the mechanism when in motion is mesmerising!

[Michael S.]

This design is well described in Conrad Matschoss's book "The Development of the Steam Engine." The two-volume book is something like the German bible for steam engines. The original edition dates from 1908. I have the two books as a reprint from 1983.

I suspect the term "Bügel" (iron) comes from "clothes hanger."

But in German, Bügel means clothes hanger and iron for ironing shirts.

Michael

[redhouseluv]

Ah okay, definitely refers to the clothes hangar and not the one for getting creases out of shirts! 

Made some progress today the omega shaped table supports are now attached to the base and are at the correct height. This section looks so small compared to the flywheel

[redhouseluv]

Fixed the table to the supports and then did the final machining of the supports to ensure both aligned in X & Y axis. Then took a took a round file to where the curved and vertical sections of the supports meet to get a smooth finish where the end mill had created a step

[crueby]

Looks like a good foundation! Its an interesting design, not the usual straight sections.   

[redhouseluv]

It's time for the rather attractive guide frames to be 'made' and full disclosure I had them fabricated or in this instance laser cut. It's not something I've thought about before, but they are in such a prominent position I wanted them to look spot on.

I snuck them into the initial photo of the castings, but you can see them out of the packaging below. They are razor sharp so need some filing, drilling then will need to be silver soldered which still makes me nervous. I need to make sure the base and the verticals are at perfect right angles before doing this

Any advice greatly appreciated

[Jasonb]

For most fabrications I make them up much like a casting with machining allowances on the bits that matter so would have made a thicker bottom and left the slot undersize or not even include it. That way you can mill the bottom and cut the slot at one setting to get it all true.

A lot will depend on whether the laser cut bottom edge of the upright is cut square or as is sometimes the case has a slight taper. If square a simple clamp or even wiring together will work. If not a bit of jigging if there is no material left to machine off after soldering. Keep any jigs, clamps and fixtures to a minimum a syou don't want them to suck all the heat out of the work. Another option if the plate sare a reasonable thickness is to drill and tap for a couple of small 10BA or M1.6 screws that can come up through the foot into the bottom edge of the plate and get soldered in.

[Michael S.]

Ah Jason was quicker with an answer.



It looks like the parts are made of brass?

If the material is thick enough, you could replace the screws from underneath and then solder them. If you solder with silver solder, the brass will be soft afterwards, and minor angle errors can be corrected by bending.