MB22 steam engine

[antopia]

Hi,
I have just started my MB22 steam engine.
boy took some time to sort out my lathe to do this
had to fit a myford cross slide so i can use my vertical slide
anyway now the lead screw is not accurate so I will have to fit a digital caliper
so the readings are better.

here is some pics more to follow when I get time.

Regards
Steven
just have to figure out how to make the River Queen seeing how me and woodwork have never met before.

just read the camera instructions 

[granath]

Hello! looks nice! i'm off to start my first build due to this weekend if everything goes as planed.

Good luck! looking forward to next update!

[antopia]

Well here is an update,It has been a little cold of late so progress is a bit slow,I have now managed to produce the top cover,bottom cover and the bedplate,as you can see I have an unusual way of producing
items.
I did find a 2.5 mm end mill so I used the vertical slide to machine the middle out from the bedplate.
as yet there are no holes,I had decided to join the 3 plates together then set them up and drill the various holes then I can use the top and bottom covers as templates for the cylinder.
The 2 center holes for the brass guides in the covers will be machined after the top and bottom (one at a time) covers are fitted using some small sleeves in the cylinder bore as a guide to drill and ream the covers,this "should" make everything line up

[steamboatmodel]

Hi Steven,
Is the MB22 steam engine from available plans or a kit?
Regards,
Gerald

[Eddy Matthews]

The MB22 engine was done by one of our members Gerald, namely Malcolm Beak. The drawings are in our Downloads section at: http://www.paddleducks.co.uk/index.php?ind=downloads&op=entry_view&iden=161

Regards
Eddy

[antopia]

Hi Gerald,
Eddy has given the link to the complete plans,
I bought a book "Model Marine Steam" by Stan Bray,the book has Malcolm Beaks steam plant
plans but unfortunately it is incomplete so I emailed Malcolm and this is how I found Eddy and Paddleducks.
there are quite a few items Malcolm has submitted and are all worth having,forwards/reverse gearbox,water level control and automatic gas burner control.

Regards
Steven

[steamboatmodel]

Thanks Eddy and Steven,
I have been looking at too many plans lately or I would have recognized this one. I have the same book and had gotten the corrections and some information from Malcolm.
Steven  it looks like you are off to a good start, keep us posted
Regards,
Gerald.

[malcolmbeak]

Hi Steven
It's been over a month since your last post and I'm wondering how you are getting on with MB22. If you need any help, please feel free to ask. I might even have some answers - it has been more than 20 years since I made the last one!
Here are a couple of pictures of one of the engines, here fitted with a pump and full flow by-pass. Full -flow because this is for a plant with water level control.
Malcolm

[antopia]

Hi Malcolm,
I think progress is slowly !,
I have drilled and tapped all the holes in the block and also top and bottom covers ,
crank shaft bushes are done and fitted to the bedplate  holes are ready to install the columns but
they have to be made yet.

I had to fit 2 digital readouts one for the vertical slide and one on the cross slide as I was not
getting very accurate results,and more problems,I have a light/magnifying glass fitted to my lathe ,its a
complete unit with small fluorescent tube in ,it is very handy, but it has some bad interference with the digital readouts
causing them to fluctuate so I can use one or t'other ,but not both!.

your pictures are a real inspiration,lovely

I have just produced a scotch crank /tender axle pump for my gauge one loco "The Project" this is why progress is also slower,
but I have been invited to a get together in early may and I wanted to make sure it runs for more than 15mins without stopping.
so the picture of the pump is quite interesting so a question what size balls did you use and how much difficulty in getting them to seal?
and ram size /stroke.?
I have found that the outlet ball is the hardest one to "get right",hit with hammer and use ball on rod to burnish,fit and test then burnish again then
complete the circle again. or am i just unlucky?

Steven

[malcolmbeak]

Steven
The pump on this engine is 0.100 bore with a stroke of ¼" and 1/8" balls are used. The gland not hides the "O" ring that seals the ram. It is type No. is 607. It is for a 0.100 shaft, and the cross section is .040. How do you cut the valve seat? I always use a cutter design I originally saw in the K.N.Harris book. If you look at the photo, you will see that the actual valve seat is slightly proud of the rest of the surface. The idea of this is that any debris will lie in the hollow below the actual seat. I'm not too keen on tapping the ball to get it to seat correctly – a very gentle tap is all that is needed, and applied truly axially. It's all to easy to get this wrong. The idea of a ball on the end of a rod and burnishing the seat is the way I usually do it.
The sizes for the D bit for 1/8 balls has the small diameter portion at 3/32 and the larger dia is 5/32. The lift should be restricted to ten thou at the most.
On the scotch crank I use a tiny ball race for the slider, with a washer either side to prevent the shaft and slide rotating.
I've added a couple of photos showing the pump and by-pass on another MB22
Malcolm

[antopia]

Malcolm,

I don't really have many model building books just very small selection,I tend to try to work things through.
seem's burnishing is well used,I have some smokers tooth powder I use for seating balls and slide valves this is
time consuming but works very well.

I have only produced a couple of water pumps 1 is a published design and the other was my own both suffer from
not seating balls on the output side.next time I make one it will have direct access to the seat so I can use a tool to face it off

yet my pop saftey valve worked first time.
 
>The idea of this is that any debris will lie in the hollow below the actual seat
thats the bit i did not do,when I made my d-bits, noted for next time.

I do understand about the lift being as small as possible, also my valves use 5/32 balls so my large diameter is only a 1/64 larger than the ball
but the small dia is 3mm or 3/4 of the ball so it seats at 45 degrees I used this from my gauge one book by JvR.

I like the use of your bearing in the scotch crank,another note for next time. mine is a built up unit cast iron sides with brass separators a bit ugly but
I can skim a few thou of the brass tubes to get the fit when it wears, it is held in place by the steel eccentric,the pump is 5/32 ram 3/16 stroke.

when I get the engine done I can see me making a pump like yours also,very well thought out,I had a discussion with my son about the pump
last night, suffice to say I was most impressed .

>I've added a couple of photos showing the pump and by-pass on another MB22

this means you have made quite a few.

Steven

[antopia]

its took a while but more progress with my mb22 engine,
thought I would have got both crossheads done but only got part way thorough 1
i don't get much time now as I travel 3/4 hour to work and back so at best only 2 hours workshop time

Regards
Steven

[malcolmbeak]

Steven
Nice to see it coming along. I like the dome nuts on top of the columns. How did you do the crankshaft - is it from solid or built up. My original one was soft soldered using comsol solder and still seems Ok. All the later ones were from solid however as it gives me a much better of satisfaction. I look forward to hearing how it performs.
Malcolm

[kiwimodeller]

Steven, when you have it ready for putting in a boat River Queen would be ideal and if you do not want to do too much woodwork Kingston Mouldings do a very good quality fiberglass hull 890mm long for her. Cheers, Ian.

[antopia]

Malcolm,
i built my crank using loctite then drilled and pinned,I had a few goes as springing was a problem,what I ended up doing was making the 2 main journals and disks in one and offset drilling 1 hole in each disk then parting the center disk and drilling this for 2 offset holes then mounting it in the lathe and glueing it there it gave me chance to move the each disk until I got everything running true,next time I will make a jig to hold each journal while glueing each part then clamping each journal so they remain true.the main problem with loctite is you need 1 thou clear so it makes things a little slack,then some would say undercut the diameter so you have 2 small "fits" then there is not time as the loctite sets in 10 seconds, did I say I had a few goes .....

I had thought of making from solid,quite a challenge, you are very brave,as close as i have done is a single throw as a 2 piece which was silver soldered, disks and crank pin in one part, then drilled for separate main journal,I must say that this crank was much stronger than the one I made as separates,so I would think your one from solid would be better.

the domed nuts I made a tool using a cut off disk in a dremmel but I only have a second tap so I have tapped thro' ,the tool shapes as it parts off

I am looking forward to having it running, there is not that much left to do now.

Regards
Steven