Pet (it's all Ralph and Gerry's fault)

[michael]

Ralph, JT, Yes paper rules! I have done my share of Architectural models in card and paper. I am glat you liked the site JT I need to do some maintenance and updating there.

The paper making experts no doubt have done all this before, I know that Christoph has done some remarkable work with paper.

This evening I did some more experiments with the paper.

a] a small roll of white bond onto some 3/64 brass rod. I started out with some superglue and then switched to carpenters glue because I found it worked faster and was not as obnoxious to work with. I made some cuts after it was glued to the rod.



b]I started to roll up the different widths to the various diameters. I was using the carpenters glue exlusively by now.



c]I added another couple of diameters all with the strips of paper and carpenters glue. then gave the lot a coat of olive drab, then flat yellow used some rembrant pastels, ochre, orange, green, brown.



d]drilled the holes for the pipng with a pinchuck and the 1.15 mm drill and the .033thou drill



d]Added a hand wheel made from a punching from a 3 ring binder hole punch, and a bit of fine brass wire stuck it onto the valve stem then dropped a little crazy glue onto it with a pin. A coat of buff paint was dribbled on with a toothpick when it had set, painted it with olive drab.



Here is Bertrand taking it over to see how it looks on the loco. (Bertrand was modified from a dollar store wierd plastic fireman a couple of years ago)

[underworld]

All looking awesome!!!!!


underworld

[JT Previa]

Your work (and your organized work-bench) are a continued inspiration.

Why not spray the injector with some gold/copper paint? I often use a metaillic sharpie or pen for this sort of really small coloring (no paint fumes!).

Thanks,

[Rockley Bottom]

That is a very neat job, I like the finish
Thank you for taking the trouble to show us so clearly
Ralph

[jameswaterfield]

Come on Michael, I'm getting withdrawal symptoms. All those reports and now nothing for days!!

James

[Gerry Bullock]

Come on Michael, I'm getting withdrawal symptoms. All those reports and now nothing for days!!

James

You're right James BUT Michael's probably going to blame me again as one of his upcoming Loco Shed items couldn't be posted for lack of photo links.
He's been repairing them.
Keep the build details coming Michael we all want to see the finished Loco - so far looking superb.
GerryB

[michael]

Oh my goodness it has been over a week! Sorry for not keeping up the pace, but I have just spent the weekend with my son (up visiting with a "LITTLE PROJECT") we got to bed last night at 3 am. up at the crack of dawn, they left an hour ago for Calgary, Safe journey.
My son is in Art and design School. he came up to visit with this simple project, yeah right! It was a marathon pull all the stops of 45 years of interactive exhibit design to bear on this "simple Project"



The deal is that as the piece of stone rises up a column of brass rotating begins to show beind the stone and it is bearing a wedding ring of white gold that he will be giving to his bride. the mother of our grandson, Boston James who incidentally got his first lesson on the Myford Saturday afternoon. He is a bit shaky yet on the technical terms, But I could tell from the drool on his face that this was where he was destined to be.


I will be duly getting back to the business at hand of completing the wonderful little crew Loco.

I am also working on a set of drawings to build this gem as a live steamer on 45mm track.

[dieselwater]

Lovely photo Michael He looks right at home there.

[chris69]

He couldn't have a better teacher,
congrats.
Chris

[michael]

It has been one of those days, I have already shoveled the equivalent of 42 cubic yards of snow today and there is now another 6 inches laying on the driveway so tomorrow if it stops now there will be another 45 cubic yards of the stuff to shovel!! The consequences of a 300 foot long driveway.

So this evening to console myself I got working on Pet again, now that Jupiters build sequences have been uploaded to the website.

First I turned some 1/2 inch brass to the rough dome shape, the dome end is solid and the bottom is turned to form a tube at the bottom exactly the same process as the Jupiter dome build.



After annealing and forming on a wooden block the dome is pretty close, I still have a bit of tweaking to do on the top of the water tank, there is a bit of a ridge which I think I can tease down. and the screw that will hold the dome on will remove any gap when it is tightened up anyway.







Thats it for tonight, tomorrow the chimney. The stack is easy enough the base looks a bit tricky though.

Looking at the photos I think I might have to lower the dome just a bit more, I'll see how it looks tomorrow. Oh yes and I did solder the tank to the rest of the boiler assembly. That was a bit tricky. I am sure that the folk who build a lot of the brass etched stuff would tell me that it is easy and to stop whining. I was looking again at that amazing little 09 brass scratch built loco this morning
http://galleryowen.fotopic.net/p61530599.html
and thinking wow I still have a long way to go to get to that standard.

[chris stockdale]

I finally remembered that 'Nipper' was modeled by Simon Bloomfield at the 16mm show in the UK in April where it won the Andrew Neale Cup.




Enjoy.

cheers

[michael]

Thanks Chris that looks like a really great model do you have any information about the builder and how he built his model?

[Geeky Gecko]

Michael, I've just read your description of rolling paper around a rod to create the valve stem (great result by the way). If I may add something, I would suggest that tearing both ends of the paper strip, rather than cutting, results in a less obvious line on the finished surface. You may already have discovered that by applying water based adhesive to the paper, and allowing the paper to expand before rolling, results in the paper gripping the rod more tightly when it contracts on drying.

[michael]

Stefan, thanks for the tip I will try as you suggest on the next roll.

Today I worked on the cad drawings for creating a complete set of plans using the builders drawings on page 40 of the crew narrow guage book, some great photos and advice from James Waterfield. Eventually the plans would enable a builder to build a full size version.

Also today I worked on the re-flairing of the dome, I felt that it was too high. and also made the parts for the chimney. I had one failure on the base and the one in the picture is the second attempt.

Here are the parts. the chimney was turned from a solid bar of .250 inch brass bored to a thin wall at the top then annealed and flaired. The base is from some brass bar turned to .290 then bored to .252 and flaired to form. and parted off and then shaped on the wooden former to the contour of the top of the water tank.



A couple of shots of the dry assembly of the chimney and dome. The screw thread sticking out from the top (2x56 UNC) of the dome will allow the safety valve fitting to tighten down the dome and hold it in place.



.

[gfadvance]

I know we keep on saying it but your work is truly inspirational Michael.

However "turned to .290 then bored to .252 " is starting to worry me .... you will be counting rivets next

Anyway I seem to remember that when you were moving house you voiced concerns over the amount of modelling stuff you had accumulated ! ... so I'm prepared to help .... just send me the bits of modelling you reject, that dome for instance, and I'll try to find a use for these bits of rubbish

I'm sure there are plenty of others out there who will volunteer to help in this way, you've only to ask

[jameswaterfield]

Lovely!

[michael]

Gordon, James, thanks for the kind words. Gordon it was the base of the chimney that failed not the dome, if you can imagine a peice of tube that looks a bit like a squashed pop, can is what is tooks like only 1/4 inch in diameter. Your welcome to have it but I have no idea what you would use it for .

[underworld]

Your metal work is amazing Michael!!!


underworld

[John New]

To assist Michael with the accuracy of this build I volunteered to take some detail photos of the valve gear bits of Pet that other people don't normally photograph whilst I was in the NRM for our SLS Centenary celebrations last weekend.

The 23 images taken are now on line on my fotopic site together with three previously unpublished general views from a 2008 trip. The one below is a reminder of what Michael's finished engine will look like:-



Plus a taster from the detail set.



Fotopic failed - images now here http://www.island-publishing.co.uk/jalb ... index.html

[michael]

Oooooh! John thanks that under shot looks great, thank you very much, this will help with the scale drawings that I am preparing from the engineering ones in the Crew Narrow Gauge book. I'm off to look at the others now.

[michael]

Hi again John, in image PC125946 where the valve rods pass through the frame spacer it appears that the two valve rods are a square section and that the casting has a rectangular hole. Can you recall if they are in fact square. and in image PC 125941 the very bottom of the valve rod casting is shown. I am assuming that this casting is the same one that is projected through the frame spacer and is just visible as a rectangle in the PC 125946.

Thanks again for taking the time to get such a great set of pictures they will be very very helpful.

[John New]

I have got a copy of Ted & Clive's book too.

What is noticeable when you look closely at the actual engine is that the Stephenson link valve gear is set up in a V shaped configuration whereas on the general arrangement drawing all the connecting rods (power) and the valve gear rodding is shown as parallel and at 90 deg to the rear axle.

In reality on Pet the set of four bores in the cylinder block are obviously parallel and 2 x piston rods and 2 x valve rods emerge and pass through the frame spacer/spectacle plate. However between the lifting link at the valve gear's front end and the crank axle the valve gear tapers so that there are only three segments on the crank axle not four. There is s a distinct gap between the two sets at the expansion link/die block end but the eccentric rods are set in the V so that all four meet at the axle end with minimal clearances.

That may be why in your PM note to me the other day you were wondered how it fitted in at the crank axle end as the spacing there seemed too tight.

(Edit) PS - Just seen your last which arrived whilst I was typing this. I will look on the high-res masters for you tomorrow as I am just about to shut the PC down for the night.

[John New]

Four new enlargements (cropped images) added to the set which partially answer the questions.

it appears that the two valve rods are a square section and that the casting has a rectangular hole

The rods where they enter the cylinder and valve chambers are both round. If they were rectangular I think packing the glands at the corners would be almost impossible and also the ends inside will be threaded to fit the piston and the valve heads. Given the loading a round section would be required to cope with the pressure on the joint and crucially to make it steam tight. The water pump drive rod is also circular.

The other ends of these rods obviously fit into knuckle joints and the links back to the crank axle are square or rectangular section.

Although very much covered in grease and fluff from the years on show you can also see the valve gear drive goes through the spectacle plate in a rectangular hole. Unfortunately I have not managed to capture a shot of the front (cylinder) side of that or the valve rod knuckle joint. I don't think this bit fits to the drawing either as there is no evidence in my photos of the support sleeve casting shown on the drawing or of the angle to the spectacle plate shown in the cross section.

[michael]

John, Thanks for the new picture, I was also amazed at the amount of grunge on the workings, I agree that it is a rectangular hole and it would then be a pretty safe assumtion that the valve rod linkages are also rectangular.
your comment about the segments on the crank axle are interesting, I will make another assumption here that the middle segment is common to lets say the bottom end of the expansion links and that the top of the expansion links would then be connected to the outer two segments which would be set at 90 degrees to each other at.

Anyone with greater knowledge of how the Stephenson valve gear works would be able to confirm whether this assumpion has any merit.

John thanks again for this information, Who knows when all is said and done my drawing might possibly be the only as built one of the valve gear and underside workings.

[John New]

I agree that it is a rectangular hole and it would then be a pretty safe assumption that the valve rod linkages are also rectangular.

No. They are half and half. Front end (see post from earlier today above) are round on both the power and valve gear rods within the cylinder castings.

Hope this doesn't make me sound too much of nerd and the following is a bit of an essay I admit. However although not a fitter I have worked on steam engines on and off as unskilled help to fitters for many years and have finally got the hang of it all.

The piston rod (power) comes out to the cross head as a round rod and that is fixed so it only goes fore and aft. The crosshead hangs from a single (or slides between a pair of) slide bars so it stays on the centre line of the cylinder bore.

From the cross-head the power link to the crank axle is via a pin fix knuckle "U" joint at the front to the crank axle. That link rod, the connecting rod, is flat bar. Pet is a two cylinder engine so there are two sets of this gear. On a two cylinder engine the crank setting is 90 deg. It drives to the back axle and the outside coupling rods also transmit power to the front wheels.

To make the steam alternate either side of the pistons in the cylinder a slider is moved to connect variously to inlet and exhaust ports. On Pet the valve rods are also round bar as far back as the expansion link, from there to the crank axle they are also flat bar. The bit I failed to photo for you adequately is how the suspension of that rod is undertaken as it too must run in just a fore and aft motion. It is possible it just hangs off the lifting link but I'm not certain that would work.

The two rods in the set waggle the expansion link as the eccentrics rotate BUT the key thing with the Stephenson gear is only one of the pair controls the movement in the valve rod at any one time the other being in neutral. The die block is moved up or down to select either the foregear eccentric rod or the backgear eccentric rod.

On Pet's left hand side is a big lever that is connected to the bell crank visible just aft of the forward axle springs. Moving the lever moves the crank, that bell crank turns a rod at 90 deg over the frames and attached to it is the lifting link that looks like a straddle crane over the four eccentric rods. That moves the die block up and down to change which eccentric rod is active thereby reversing the engine. Top rod is usually foregear.

On Pet as I stated yesterday the sneaky design dodge is the V configuration you can clearly see in the underside shot taking four units at one end of the valve gear down to three segments on the crank axle.

The cranks have to be at 90 deg as there are two port movements to each stroke (Inlet and exhaust) making four per rotation. The 90 deg setting means inlet and exhaust cycles should be opposed across the pair of cylinders. It also stops the coupling rods getting crossed which is why even an electric powered steam engine has to have the axles quartered. If you look at the photo of the crank axle you can see the 90 deg offset setting quite clearly.

On a real 3 cylinder engine the crank settings are 60 and 120 respectively but on a model you have to quarter.