A Tandem Compound Mill Engine

[deltatango]

In my former world of w##k the saying was "if it hasn't been written up, it hasn't happened" so I guess it's time that I started a build log for the current engine.

The choice of engine for this project is the result of my interactions with MEM so I hope you all like it, particularly Tug and Bob Potter who have played their parts in getting this one started. Tug has written of the origins of the Arnold Throp/Peter Southworth compound mill engine model in "Tug's Corliss Tandem Compound Project" build log so I won't duplicate too much of that here, just enough to set the scene.

Arnold Throp, who was an apprentice with Cole Marchent & Morley, engine builders in Bradford (Yorkshire, UK) described a model of a typical small-to-medium sized mill engine in "Model Engineer" in 1982 but didn't give any construction details and as far as I know no such details have been published. The design was worked on by Peter Southworth and he evolved five basic versions and made (or modified) patterns and was the original supplier of castings. Since then the availability of castings has been patchy. At the Forncett day out two years ago I saw Tug's progress with his all-Corliss valved tandem compound version and was impressed with it (both the design and the workmanship!). At that time Bob Potter was running "Southworth Engines" and supplying drawings and castings for boiler feed pumps and for the mill engine and he sent me a set of drawings.  The engine was, just, within what my machines could deal with and I was very taken with the idea of building one so parted with the money. Bob had given up on sending castings via the post/couriers but he, very kindly, delivered the 23 kg of metal to friends of ours "to await collection". Customer service indeed! Since then the Southworth range has been taken over by Blackgates Engineering and their 2019 catalogue only lists the feed pumps, I really hope that Arnold and Peter's legacy isn't going to be forgotten!

Of the five versions shown on the drawings my choice was the tandem compound with Corliss valve HP and slide valve LP cylinders and an "air pump" (spray condenser, really). The cross-compound versions were attractive but too bulky for easy storage, transport or display. The tandem is long but will at least fit on a shelf.

As I've done with previous projects I re-drew the design using the "Alibre" CAD package and here are three screen dumps of the results:







Next post I'll put in a drawing and make a start on the big bits i.e. the flywheel and crankshaft.

David

[crueby]

Oh, now that is a real beauty of a design!!  How big will the model be?


Hey, shop elves, break out the popcorn!!   

[deltatango]

Great to have you watching and commenting Chris!

The baseboard as drawn is just over 1 m long and the flywheel is 250 mm OD. The Hercus "260" lathe swings, not too surprisingly, 260 mm. As you will see soon this is a tight fit.

Hope you have lots of popcorn on hand as this won't be a quick build!!

David

[Larry]

Great looking design. Anxious to follow your MEM Corliss build.

[cnr6400]

"OK Chris, I'll back the dump truck full of     into your cellarway now, and then go get another load for  me"   

CAD looks great David, look forward to watching the build. Have you checked the workshop door to be sure you can get it out when finished? 

[deltatango]

Thanks, good to have you along Larry and cnr!

It will go through the door - endways on. I just hope I get it finished before I'm too old and feeble to lift the damn thing.

There is also the important question from the "local authorities" as to "where do you think you're going to put this one?".

David

[JackPick]

Wow, there's some work in that one David. Nice CAD model too.
Best of luck.
John

[MJM460]

Hi David,

Looking forward to following along.  It will be an interesting build.

MJM460

[john mills]

Hi David

  I  too will follow your build  it will be an interesting model in full size these engines must have been impressive machines to watch working and i am sure your model will be too.
     
       John

[Jo]

Nice to see the construction of another of Arnold's engines David. 

I am building his Cross Compound version ... its rather huge 

Jo

[deltatango]

John, MJM, John and Jo, it's good to have you following.

Jo, what progress have you made with the cross-compound? It would be huge bordering on humongous...

John M these machines are indeed very impressive to watch and many of them ran for a century or more with only replacement of normal wearing bits.

OK, just been called for a meal, more later.

David

[Jo]

Jo, what progress have you made with the cross-compound? It would be huge bordering on humongous...

I didn't get very far as having finally found a big enough board to sit it on I decided I needed to find a display/storage arrangement for it first. It is too wide to sit on a side board or in a display cabinet so I toyed with the idea of converting a coffee table to mount it in but got no where so there it sits 

Jo

[deltatango]

Jo, thanks for the picture. I've seen some pictures of completed cross-compounds and it was thinking about those, and where we could put them that convinced me to go for a tandem. However, it would be great to see yours restarted, could my efforts inspire you??

It wasn't just seeing Tug's model that set me off, I have family connections to NW England so a representation of an important part of the history of Lancashire has meaning for me.

The model is based on a design by Arnold Throp, published in Model Engineer, 20th August and 17th September 1982. Arnold T described it in general as “… representative of the smaller types which were made in great numbers from about 1860 onwards in this country for driving textile mills, …”.

As the model is not intended to represent any particular full size engine it can have an invented back-story. My mother’s family were all from Burnley (Lancashire, England) with her father’s family (Read) being road and general contractors (“Paviors and Contractors” in the trade directories of the time) and her mother’s (Easton) were brush makers. The Eastons made every sort of brush from ladies hair brushes to the rotary brushes for road sweeping machines but their main source of income was sweeping and specialised brushes for the cotton industry.

Based on that background I have invented the engine building firm of “Easton and Read, Engineers, Burnley”. As these engines were often given female names this one can be “Mary” for my maternal grandmother. An engine this size was quite likely to have driven a weaving mill in the Burnley area, spinning mills used much larger engines. All I have to do is get the model to the stage where a makers plate and name plate are needed...


After collecting the castings I re-packed them into a small trolley case and spread the smaller ones out among our other bags (the maximum weight for any single item of luggage is 23 kg, same as the total of the castings so we had to keep the case weight down). I don't think the person on the check-in desk had ever had a case that small that weighed so much but she accepted my explanation of the contents - without much idea of what they were, I suspect.

After unpacking the set looked like:



and, with an embryo crankshaft included:



Enough background, time to get on with cutting metal, there's a heck of a long way to go!

David

[scc]

Great stuff.........I'm in     Terry

[jadge]

Should be an interesting build. Wow, one metre, that's a pretty big model. The castings look rather nice with good definition.

Andrew