Potty Over Crank Wall Engine

[NickG]

Wow, that's really impressive Stew - it is interesting motion to watch too. Well done, a great feat to see something you like in a museum and turn it into a scale model. 

Nick

[Dean W]

Oh, it turned out so well, Stew (naturally!).  What a fine job, and the sound is pure symphony.  It is definitely one
of those "watch-it-run-for-hours" engines, and I watched the vid more than once...  A lot more than once!
Thanks for a great build thread!

[Stilldrillin]

That's pure, "Poetry in Motion", Stew!  

Blummin well done!  

David D

[sbwhart]

Thank you all again Chaps

So far its bin an interesting project, some of you Guys have commented on its size, it did come out bigger than I had in my minds eye, but in its original state it's not a very big engine, it would comfortably fit in a suite case, the model loco guys like to build narrow gauge Locos as they come out as large engines I thinks its something to do with scaling. The original engine has a fly wheel of about 24" dia I used a 7" fly wheel about 1/3 full size, and scaled everything from that, I think if I had used a 4" fly wheel some of the parts would have come out too small to comfortably make.

I don't intend running it on steam I don't think its performance on steam would be very good as I made the steam galleries on the small size.

I went away from the drawing I posted quite a bit:-as the build progressed I saw better or alternative ways of doing things, so at some point I will update them.

When I come to finish the engine off I want to round the sharp corners off and fill internal corners with something so that it looks more like a casting, can any of you guys suggest a filler.

Stew

[Bogstandard]

Stew,

You can use car body filler, but I found it very messy and hurtful on the fingers getting it to the right shape after it has set. You don't really have the time to get things perfect before it goes off.

When modifying parts on the figures I used to do when making model boats, I used Milliput.

Mix the two parts of the putty together, push it into where you want to change the shape, then while still soft, mould and carve to shape, just like modelling clay. Once to roughly the right shape, using wet fingers, blend everything in position so that it looks like part of the original. Leave to set overnight and paint straight over the top, you would never be able to tell it wasn't part of the original. You can even texture it if needed, before it goes fully hard after a couple of hours.


John

[andyf]

.... When I come to finish the engine off I want to round the sharp corners off and fill internal corners with something so that it looks more like a casting, can any of you guys suggest a filler.

Stew

Superb job. Like others, I was surprised by its size in the video, or conversely how tiny your hands are 

I've used "Milliput" for filling (Google it). If you haven't met it before, it is an epoxy resin based filler which comes as two sticks. Cut off an equal length from each and mush then together between your fingers. It has a putty-like consistency and will stay put once in place, rather than being runny like Araldite. It smooths over quite well with a wet finger.

Andy

[doubletop]

Stew

I'll post it here as well as John will know what this stuff was

"Hemetal" (or some such) came to mind, it was a metal based filler the riggers used in the RAF for bunging up things (can't think what). I believe it was in the Hematite gasket people product range. Had a dig around and Hematite is now Loctite and nothing about Hemetal

I did find this though that looks similar

http://www.eal.com.au/hypoxy.php?PHPSESSID=cc353e31e70189b5218aca111a6e97ec

Pete

[Bogstandard]

Pete,

Hermetal or Doublebond, the stuff we used came in two flat round tins

Milliput is almost exactly the same.


John

[Jasonb]

And if your fingers are too fat to give the desired radius just glue a suitable ball bearing to a bit of rod or tube, dip in water and use that to form the fillet, you can buy modeling tools which do the same thing. Duro and Magic Sculpt work in teh same way but in the UK Miliput will be the easiest to find.

J

PS The white superfine is the best of the colours

[Bogstandard]

I forgot to mention, Stew brought the engine round for me to have a look at the other afternoon.

Even in it's unfinished state, it has a great 'wow' factor, and how Stew managed to build it from a few photos and rough measurement defies belief, especially in such a short build time.

It is one of those engines that, when finished, needs to be stripped down, and a full set of good quality drawings made up of it, then share it with the world.


Great achievment Stew.


John

[JimM]

That's a cracking engine Stew, it looks and sounds great especially on the slow tickover - I'd be well chuffed if I could make something half as good one day

Would JB Weld be any good for filling the corners ?  It's a bit sticky/messy to work with but dries rock hard and is the right colour (sort of)

Cheers

Jim

[sbwhart]

Thanks John

I've gone away from my origonal drawing quite a bit when I was doing the build all the main features are their but as the build progress I saw or learn't better way of doing things, so at some point I will ammend the drawings and post them up her.

I took the engine to our club open night where members showed off their work and gave a little talk on the project and it got lots of interest and thats from a club that is very much locomotive based and a number of members asked for compies of my drawing even with the warts.

Thanks very much Jim I've just ordered some milliput from fleabay so when I get to do the fillets I'll let you all know how I got on with it.


Stew

[ksor]

Cast iron is real filthy stuff to work with, looks like I can join John's black hand gang.  

Potty Over Crank Wall Engine


Stew

Hi Stew !

I think it's a "little" dangerous working with a wedding ring - I remember seeing some horrific images where the meat was pulled from the bones of a finger because of such a ring.

But oh, what nice peace of work you do  !

[sbwhart]

Hi Ksor

Thanks for the reminder I've seen pics of fingers pulled off due to rings also :-not nice.

And thanks for your kind comment on my work.

Stew

[sbwhart]

Well, time to pic this back up again by making a start on the governor in fact I've been agonizing over it for a couple of weeks for some reason I've been full of self doubt and uncertainty, I've drawn and redrawn the governor up 1/2 a dozen times changing my mind as to type and size, eventually I gave myself a good talking too:-just get on with it and stop p******g around.

So her we are first bit the little spinning things that hold the arms, making small parts can be a bit of a pain if you don't get the machine sequence right, you can end up with nothing to hold onto.

So started off on the lathe and machined out the outer shape and reamed the bore out 3mm, I'm making the two out of the same bit of bar one at each end.

Her they are one at each end

Potty Over Crank Wall Engine

Then over onto the mill gripped in the four jaw self centering chuck, centre the chuck on the centre line of the quill, zero the dials, then with a 2mm slot drill, mill the slot across the end, then with a bigger end mill, mill flats either side, flip it round and repeat on the other end.

Potty Over Crank Wall Engine

Then over to the vice first set the quill on to the centre of the bar, with a ruler or straight edge in the slot grip it level in the vice, index to position and drill through 0.8mm for the pivot pin.

Potty Over Crank Wall Engine

Back onto the lathe and part them off, doing them this way you had the bar to grip onto.

Her they are on a length of 3mm stainless that will be the spindle with a bit of 0.8 piano wire through pivot hole.

Potty Over Crank Wall Engine

Stew

[saw]

Nice work 

[Rob.Wilson]

     good start Stew    ,,,,,,,,,,,,,,,,,,,, looks fiddly 



Rob 

[sbwhart]

    good start Stew    ,,,,,,,,,,,,,,,,,,,, looks fiddly 


Rob 

You can say that again

     good start Stew     ,,,,,,,,,,,,,,,,,,,, looks fiddly   

 

I can see me losing some of these bits on the floor.

 That will turn the air blue

 

Stew

[Stilldrillin]

Stew.
I looked at your last pic. My first thought was.... They're tiny, I would have to make a few spares! 

Looking great. Well done! 

David D

[sbwhart]

Thanks Dave.

Yes, the parts are small and fiddly, but one of thing I was agonizing about was getting the scale of the governor correct, to often you see engines dominated with over scale governors, small governors don't work as well but after all they are not working engines as long as they look right and work something like is the important thing.

Any way on with the link arms first the arms that will hold the balls.

Turn and thread a small length of 4 mm dia bar M2 I took care to get the length the same on both bars I don't want the balls hanging odd

Potty Over Crank Wall Engine

Then carefully mill the 4mm dia into 2mm square.

Then drill 0.8mm for the links.

Potty Over Crank Wall Engine

Her they are fitted.

Potty Over Crank Wall Engine

That was the easy bit now for the more complex yolk link.

First mill up the shape in a chunk of mild steel more than enough to make two links.

Potty Over Crank Wall Engine

Zero the mill on the x, Y edges of the bar, and drill 0.8mm holes in correct position as deep as the slender drill would go, fast speed, drop of cutting fluid and peck the drill in and out to clear the swarf.

Potty Over Crank Wall Engine

Now for milling the slot, the arms will only be 1mm thick and as the slitting saw will tend to spring the arms open the slots were cit in the bar well away from the edge to give a thicker section I'll mill them to size later.

Potty Over Crank Wall Engine


With thin sections its important to use good sharp tools if they are blunt the part will be bent, so with a new end mill skim off arms until 1mm thick, then mill step, to form the yolk.

Potty Over Crank Wall Engine

With another bigger dia slitting saw cut the link from the bar leaving plenty of meat around the arms for finishing later.

Potty Over Crank Wall Engine

The second arm was just a repeat of the first, this is it being split off, I was a little lean on material, but their was just enough.

Potty Over Crank Wall Engine

The links were flipped over and the other side end milled to size sorry no pics.

The hook was filed to shape.

Potty Over Crank Wall Engine

I left them over long to give something to grip on only cutting them of to length as a last op.

Here's one finished with its mate.

Potty Over Crank Wall Engine

And the finished bits assembled, they still need a bit of a clean up but not looking too bad. It will be fitted with some 3/8" phosphor bronze balls, when I work out a way to drill and tap them.

Potty Over Crank Wall Engine

Stew

[saw]

Good work looking fantastic 

[raynerd]

It is looking really great Stew ! 

[andyf]

That looks great, guv'nor!

Andy

[lordedmond]

Stew


just bung em in the three jaw on the lathe drill and tap there

grip them lightly and they will not dimple , but they will get hot ,very hot . they are a pain to drill , don't ask how I know 



Stuart

[mklotz]

This article...

http://www.homemodelenginemachinist.com/index.php?topic=6852.0

describes how I held some (spit) wooden balls to drill them.  However, I have successfully used the same technique to hold and drill steel and brass balls.