Author Topic: A Small Inverted Vertical Steam Engine  (Read 26913 times)

Offline ProdEng

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A Small Inverted Vertical Steam Engine
« on: September 30, 2012, 09:28:24 AM »
This build was started three months ago and even though it is documented elsewhere I thought I would post some of the interesting bits and the rest of the build here.  The model is based on a high speed inverted vertical of the type commonly used to drive generators.  While the prototype had a 4" bore the model has a bore closer to 1/2" making the scale 1:8.  The design was modeled in Inventor and even at this advanced stage of build is still incomplete!



My modelling interest lies in making small models of small engines with rotative pumps catching my interest.  With few published designs available the pumps appeared too difficult to tackle and the idea of this build was to develop technique to see if a pump would be possible for me.

To my inexperienced eye, the most difficult part of scale modelling steam engines is to make the casting look believable so naturally that is where the build started.  I include a 3-D model of the standard so the objective can be seen.



Aluminium was chosen for the standard to make it easy to work.  The process consisted of milling filing and scarpind followed by lots of sanding.







The standard took a while to make but, when broken down to simple steps, was not terribly difficult.  The end result was very encouraging.



Most of the rest of the build to date has been pretty standard machining most of which I have picked up from other peoples work :)

So this is the state of play up to a couple of weeks ago when I stopped to make my die holder set up.



More soon!
Jan in Perth

Offline ProdEng

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Re: A Small Inverted Vertical Steam Engine
« Reply #1 on: September 30, 2012, 09:39:25 AM »
The next part to make was the cylinder cover.  As I have no bar stock, a piece of 1" plate was sawn and mounted in the 4 jaw to make a piece.  The tool used to turn the recess in the top of the cover is a piece of 1/8" HSS mounted in a home made holder.  Grinding a small tool from 1/8" round is very quick and inexpensive.



After turning the part was mounted in the mill to drill the mounting holes.  I love setting up using an indicator, there is something about getting the job running so there is no deflection of the needle even if it is not necessary!





A quick trip back to the lathe to part off to width and it was done.  No picture of the finished part yet coz I forgot to take one :slap:
Jan in Perth

Offline sbwhart

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Re: A Small Inverted Vertical Steam Engine
« Reply #2 on: September 30, 2012, 09:45:31 AM »
Nice work  :ThumbsUp: :ThumbsUp: :ThumbsUp:

Interesting model I like your 3D drawing what software are you using ?.

Stew
A little bit of clearance never got in the way

Offline peatoluser

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Re: A Small Inverted Vertical Steam Engine
« Reply #3 on: September 30, 2012, 09:57:24 AM »
that standard came out spot on. certainly looks a casting
a few questions if I may?
what's the overall height of the engine?
how did you attach the feet to the standard?
what's the stroke?

thanks in anticipation

peter

Offline ProdEng

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Re: A Small Inverted Vertical Steam Engine
« Reply #4 on: September 30, 2012, 10:07:06 AM »
Thanks Stew.  The software is Autodesk Inventor, I use it at work as it is well beyond my pocket.  Modelling allows checking clearances before building the parts as well as providing  nice working drawings very quickly.

Peter, the engine is about 6" o/all.  The feet on the standard are recessed in pockets and then glued with JB Weld.  The stroke is 18mm.  Thanks for your interest.
« Last Edit: September 30, 2012, 10:53:58 AM by ProdEng »
Jan in Perth

Offline vcutajar

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Re: A Small Inverted Vertical Steam Engine
« Reply #5 on: September 30, 2012, 10:17:11 AM »
Hi Jan

Nice to see your engine here also.  Keep it up.

Vince

Offline ProdEng

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Re: A Small Inverted Vertical Steam Engine
« Reply #6 on: September 30, 2012, 11:44:25 AM »
Greetings Vince,

Lots of familiar names here!
Jan in Perth

Offline Don1966

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Re: A Small Inverted Vertical Steam Engine
« Reply #7 on: September 30, 2012, 12:58:09 PM »
Hi Jan, glad your posting your engine here although I was still following it on the other forum. Looking great and waiting for you to complete.


Don

Offline zeeprogrammer

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Re: A Small Inverted Vertical Steam Engine
« Reply #8 on: September 30, 2012, 01:20:20 PM »
That's an interesting engine. I've never seen one like it.

The standard came out excellent.
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
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Zee-Another Thread Trasher.

Arbalest

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Re: A Small Inverted Vertical Steam Engine
« Reply #9 on: September 30, 2012, 02:59:37 PM »
Nice work on the Standard, came out very well! :ThumbsUp:

Offline Jo

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Re: A Small Inverted Vertical Steam Engine
« Reply #10 on: September 30, 2012, 05:32:12 PM »
That standard looks the works :ThumbsUp:. Question: How did you attach the feet to it?

Jo
Enjoyment is more important than achievement.

Offline smfr

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Re: A Small Inverted Vertical Steam Engine
« Reply #11 on: September 30, 2012, 05:42:20 PM »
Great to see this build here, Jan. I look forward to the next update!  :ThumbsUp:

Simon

Offline ProdEng

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Re: A Small Inverted Vertical Steam Engine
« Reply #12 on: October 01, 2012, 11:51:48 AM »
Thanks for all the positive comments, it all helps keep the motivation up :)

A Public Holiday today allowed a bit more work.  The victim this time was the valve chest cover.  Nothing too taxing here, the part was marked out then the pocket milled to the lines by eye.



The holes where placed using the dials.



Then the whole lot was deburred and the machining marks polished off.  The little brass bar is an aid to polishing I saw used by a watchmaker.  In this case the end is turned down to 1/8" and the end milled at 30 degrees.  A narrow strip of abrasive is wrapped around the end and you polish away!  Brilliant for getting in the corners and very kind on the fingers.  I find myself admiring clock and watchmakers more recently, they use some very handy techniques.



Now I have to finish the design before any more machining.
Jan in Perth

Offline b.lindsey

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Re: A Small Inverted Vertical Steam Engine
« Reply #13 on: October 01, 2012, 01:40:06 PM »
Nice to see this one posted here as well Jan.  Its all looking great so far and look forward to seeing more.

Bill

Offline ProdEng

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Re: A Small Inverted Vertical Steam Engine
« Reply #14 on: October 07, 2012, 05:59:38 AM »
Only managed a few hours in the workshop this weekend due to life getting in the way :)  Next part to make was the valve chest.  Most of this is pretty standard machining, a repeat of steps performed on other parts.  The Sherline mill is good for drilling holes up to 1/4" after which you need to mill or bore.  Having recently received a boring head I decided to bore the hole in the valve chest to remove material that would otherwise be milled.



With the hole enlarged close to the marked lines the rest was milled out following the lines by eye.



The hole for the valve rod was drilled along with the counterbore for the gland.  The hole for the rod is 2mm diameter at the top and 1.5mm at the bottom.  By drilling the surface of the bottom part with the 2mm drill I ended up with a nice countersink for the 1.5mm portion.



I have started the fitting process of the assembly and needless to say it needs a "bit" of adjustment.  At least it's provided the opportunity for another mock up shot.



That's it for this week, a lot of detail work remains but most of the major parts are now done.
Jan in Perth

 

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