Author Topic: A Small Inverted Vertical Steam Engine (Read 27397 times)

ProdEng · « **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!

ProdEng · « **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

sbwhart · « **Reply #2 on:** September 30, 2012, 09:45:31 AM »

Nice work

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

Stew

peatoluser · « **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

ProdEng · « **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.

vcutajar · « **Reply #5 on:** September 30, 2012, 10:17:11 AM »

Hi Jan

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

Vince

ProdEng · « **Reply #6 on:** September 30, 2012, 11:44:25 AM »

Greetings Vince,

Lots of familiar names here!

Don1966 · « **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

zeeprogrammer · « **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.

Arbalest · « **Reply #9 on:** September 30, 2012, 02:59:37 PM »

Nice work on the Standard, came out very well!

Jo · « **Reply #10 on:** September 30, 2012, 05:32:12 PM »

That standard looks the works

. Question: How did you attach the feet to it?

Jo

smfr · « **Reply #11 on:** September 30, 2012, 05:42:20 PM »

Great to see this build here, Jan. I look forward to the next update!

Simon

ProdEng · « **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.

b.lindsey · « **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

ProdEng · « **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.

smfr · « **Reply #15 on:** October 07, 2012, 07:23:28 AM »

That's looking great! Now I see why there's that slot in the column; it's for the crosshead guide. Those one-sided crosshead guides always make me a little nervous; you'd think they might go off on a kilter and bind. I'm sure yours will be fine though!

Simon

steamer · « **Reply #16 on:** October 07, 2012, 12:53:53 PM »

Actually that design is pretty old and tried and true in the steamboat community. Lots of 12"-FOOT boats out there with slotted crosshead guides....they work fine.....Long rods...or "long legs" (2 1/2 times the stroke or more) as it's put help with reducing the side load on any cross head.

Dave

zeeprogrammer · « **Reply #17 on:** October 07, 2012, 01:13:52 PM »

Almost there Jan and it's really look good. That last pic is very impressive.
Looking forward to the run.

Don1966 · « **Reply #18 on:** October 07, 2012, 03:18:02 PM »

Jan your engine s turning into a awesome looking engine with all the look of casting. Great job so far, what have you in mind for the flywheel?

Don

vcutajar · « **Reply #19 on:** October 07, 2012, 04:08:29 PM »

Keep up the fine work Jan.

It is starting to take shape.

Vince

steamer · « **Reply #20 on:** October 07, 2012, 07:15:17 PM »

Saw the attached over at Preston Services.....sweet engine from a 100 years ago ....You'll notice the cross head design.

Dave

ProdEng · « **Reply #21 on:** October 08, 2012, 11:31:32 AM »

Thanks for all the kind and encouraging comments, work has slowed over the last few weeks so I need all the help I can get

The little engines designed for generator duty where limited to 60psi steam so not a lot of force on the crosshead I guess.

Ah, the flywheel, good question Don! If I had a good idea the flywheel would be made by now. I am torn between the "safe" hog it out from the solid but I know I should at least attempt a fabrication. Using a casting would be a bit of a compromise and anyway these small engines had odd spindly flywheels that I would like to capture the feel of. So the answer is there is no design yet but it can't be put off for much longer $:-\$

Dave, that marine engine is lovely and would surely make a great model. The next project is going to be a pump but after that I might have a look at a small marine engine.

arnoldb · « **Reply #22 on:** October 16, 2012, 06:35:48 PM »

Good going Jan

- I'm a bit late to say anything, but have been following along.

I also tend to like spindly flywheels, and have had some success fabricating them. It's one of those things that you just have to take a deep breath, tell yourself you CAN do it, think things through and do it

Kind regards, Arnold

ProdEng · « **Reply #23 on:** October 18, 2012, 01:24:21 PM »

Thanks for the little push Arnold, the design is done

The O/D of the flywheel is 95mm (3 3/4") and the spider is 2mm (5/64") thick. The spider is a lot like a clock gear wheel and will most likely be made from brass. Need to start looking for materials. The angled return on the rim will have a radius turned in it when the whole thing is soldered together. Exact manufacturing process is yet to be decided!

ProdEng · « **Reply #24 on:** October 19, 2012, 01:54:25 PM »

Decided to make the valve rod in one piece but this turned out to be a poor choice. While gripping the 2mm shaft in order to mill the head, the force of the cut caused the part to spin ruining the head. After a few choice words I checked one of Arnold's Elmer's builds and made a separate head to be soldered on. The soldering turned out to be very easy and the fillet of solder improves the appearance

The valve and valve nut should be up next

NickG · « **Reply #25 on:** October 19, 2012, 04:27:42 PM »

I remember watching this build too. Looks great Jan

steamer · « **Reply #26 on:** October 20, 2012, 01:39:37 AM »

There's a reasonable way to deal with a flywheel! ....like that!

Dave

arnoldb · « **Reply #27 on:** October 23, 2012, 06:05:57 PM »

Good going Jan

I've been meaning to start silver soldering the valve rod heads - it's just been a bit daunting up to now. The next one up I'm definitely going to try and silver solder, as it matches the rest of the brass/bronze better in colour.

I like the way you want to make the flywheel

Kind regards, Arnold

ProdEng · « **Reply #28 on:** October 27, 2012, 09:20:08 AM »

Thanks for the comments, helps to keep the pictures coming

No material for the flywheel so the valve became the next victim. The bar of brass I have is a bit oversized so four sides where milled to get a bit of stock with square sides. The slots where used using a four flute 1/16" stub end mill. The short cutter makes me feel a lot more confident that the end will not drop off but is only useful for shallow slots.

The bar was inverted in the chuck to mill the pocket, again using the 1/16" cutter.

Finally the part was "parted off" with a 1/8" diameter cutter.

That's probably it for this weekend, shop time has been short recently. I look forward to a three week holiday at the end of the year

gbritnell · « **Reply #29 on:** October 27, 2012, 12:21:25 PM »

It sure looks great in it's natural finish. Another option for cutting small slots is to use a slitting saw. Although I sometimes use even 1/32 end mills in my mill I try to avoid using the very small ones because of the lack of rpm on my machine.
gbritnell

ProdEng · « **Reply #30 on:** November 03, 2012, 09:46:56 AM »

Hi George,

The Sherline runs up to 2800 rpm and, being such a light machine, provides good feel of feed force even with small cutters. I intended to use a slitting saw to cut the part off but the bar was too long to mount vertically and I was too lazy to rotate the mill head!

With most of the parts made I have now turned my attention to doing a bit of sculpting and finishing. The base still needed to be shaped and boss added to mount the stay bar. A draft angle of 2 degrees was milled on the base using the angle table. After milling the edges where rounded with a file and sanded to blend.

I only had a vague idea of how the boss was to be made and fitted. Started off by milling a pocket in the front of the base to take the boss. The base is held down with two clamps and there is a parallel between the base and angle table to resist rotation.

Leaving the base on the mill, I started to turn the boss. A test fit showed that the parts where in alignment.

Before gluing the boss was shaped to provide access for the fixing nut. The boss will be fared in using JB Weld followed by a bit of filing and sanding.

A mountain of filing and fitting now awaits my attention but at least assembly can follow just behind

Don1966 · « **Reply #31 on:** November 03, 2012, 10:11:48 AM »

Great work Jan, I am really getting anxious to see you complete it. The flywheel will be a challenge and an interesting bit of work. I look forward to seeing it built. Your base and standard looks great.

Don

zeeprogrammer · « **Reply #32 on:** November 03, 2012, 12:49:10 PM »

Nice post on making that valve. It helped me to see it.
And the base came out real good.

smfr · « **Reply #33 on:** November 03, 2012, 03:48:11 PM »

Nice work! Is that a shop-made angle table? It looks pretty handy.

Simon

ProdEng · « **Reply #34 on:** November 11, 2012, 01:18:41 AM »

Thanks for the comments guys.

Simon the angle plate is a Sherline acccesory and it is designed to fit a vice, lathe chuck or rotary table. Here is a shot of the rotary table mounted to make a leadscrew dial for my lathe.

Some progress has been made with the engine, mainly fitting work. The crank, rod and crosshead now play well together

Still no material for the flywheel, brass is very expensive. Looks as if I will make it from 1/2" steel plate, not very elegant but effective.

ProdEng · « **Reply #35 on:** November 18, 2012, 07:36:01 AM »

Work started on the flywheel, I have a piece of 16mm steel plate so the price was right! I cut a very rough blank with an angle grinder and improved it with the bandsaw, wearing the blade out along the way. The flywheel is only 11mm thick when finished so a lot of material to remove. A 95mm diameter disc fits in the 4 jaw chuck but the C3 is less than happy machining steel of this size. There simply is not enough power or rigidity in the machine. As a result progress is SLOW and quite boring. Anyway after lots of hours of tiny cuts the disc is turned both sides and after the bore is finished I can move to the mill to do the spokes. The picture shows the first operation, the other side looks the same when it is finished

.

ProdEng · « **Reply #36 on:** November 18, 2012, 11:16:39 AM »

Managed to squeeze in another hour so I bored the flywheel to fit the crank and slipped the flywheel on to see how it looks. It looks a bit massive with no spokes but the sizes where taken off a drawing so it should work out.

gbritnell · « **Reply #37 on:** November 18, 2012, 12:35:02 PM »

Jan,
A big flywheel will work better than a small one but I agree it does look a little large compared to the engine.
gbritnell

ProdEng · « **Reply #38 on:** July 21, 2013, 03:03:46 AM »

Well it has been a while since anything was done on my engine but I have been distracted by some of lifes ugliness. Getting back to the workshop was a bit strange, everything left exactly as it was with, to my eternal shame, thin layers of rust on a few things!

I wasn't looking forward to milling the flywheel or to making a tooling plate to go on the RT but in the end it went reasonably well and I learned a lot along the way. The machined finish on a lot of the spokes loked as if it had been chewed out by a rat but a bit of file work saved the day

Hope to be able to get some regular machining sessions going now and also catching up with what everybody else has been up to.

Captain Jerry · « **Reply #39 on:** July 21, 2013, 03:30:25 AM »

Hi Jan

It is great to see your return and to see this project revived. She is a beauty and you have shown a good eye for detail and proportion. I'm also glad that life's challenges have allowed you rejoin us.

Jerry

vcutajar · « **Reply #40 on:** July 21, 2013, 04:51:32 AM »

Hi Jan

Great to see you back at it. Really looking good.

Vince

Don1966 · « **Reply #41 on:** July 21, 2013, 02:30:37 PM »

Hi Jan, I am also glad to see you back. You engine needs finishing and I for one would like to see it running. Nice work on the flywheel and engine.

Don

steamer · « **Reply #42 on:** July 21, 2013, 02:58:36 PM »

Quote from: vcutajar on July 21, 2013, 04:51:32 AM

Hi Jan

Great to see you back at it. Really looking good.

Vince

Absolutely!....welcome back Jan!

Dave

NickG · « **Reply #43 on:** July 21, 2013, 03:28:29 PM »

Really nice looking engine, well done

Jo · « **Reply #44 on:** July 21, 2013, 07:30:41 PM »

Welcome back Jan looking forward to seing more of this engine

.

Any chance of jotting down a few notes of what you leant? I for one still have to learn how to use a rotary table

Jo

ProdEng · « **Reply #45 on:** July 22, 2013, 11:54:22 AM »

Thanks for all the kind comments, it is indeed good to be back

Jo, this particular encounter with the RT was a comedy of errors. First lesson was that the RT needs to be centered on the spindle and then the work centered on the table. I turned a dowel to centre the tooling plate on the RT and used another dowel to locate the flywheel on the tooling plate. The whole lot was then centered on the spindle in one go and I have no idea why I thought that would work! Needless to say there was an error resulting in the spokes not being quite radial! Next mistake was to use the cutter supplied by Sherline with the machine. This is a double ended affair with a 3/8" shank that fits in a holder screwed onto the spindle nose. In soft metals this works fine but not on steel; the tip of the tool is too far from the spindle nose and provide lots of leverage to twist the column. I persevered with this until the cutter was blunt, switched ends only to find that this end was already blunt. Sanity returned partialy and I fitted another cutter into a collet that fits directly into the spindle so reducing that overhang. Things improved briefly until the cutter snapped off. I had been using slot drills up till then, logical for a slot but then tried an end mill with much better results. By the end of the job the end mill was worn out as well. The moral of this story is to buy decent tooling in the first place.

When I took the flywheel off the RT I was so dissapointed it nearly went flying across the yard

After a quick clean up with a file it looked a lot better but will need filling before painting. The good news is that I am more likely to have another go at machining a flywheel rather than less

b.lindsey · « **Reply #46 on:** July 22, 2013, 02:05:35 PM »

Let me add my welcome back too Jan. As a fellow Sherline user I very much enjoy seeing what others are doing with theirs.

Bill

ProdEng · « **Reply #47 on:** July 23, 2013, 11:28:19 AM »

Tanks Bill. I like my Sherline mill, at the moment it has more capability than I do! With some good tooling and better setup I am confident it will do all I need.

Dave Otto · « **Reply #48 on:** July 24, 2013, 01:07:37 AM »

Hi Jan

Good to see you posting again; this has been an interesting project and I'm glad to see it continue.

I really do like the large flywheel; it makes the engine look like it would be capable of some serious work!

Dave

ProdEng · « **Reply #49 on:** July 24, 2013, 12:38:31 PM »

Thanks for dropping by Dave. The flywheel is about 1/2" too big according to dimensions given by Haeder in his book on steam engines and the rim is a bit heavy. The model is of a small engine having 4" bore so the overall height of the engine is about 56" and the smaller engines have disproportionately large diameter flywheels. If I where dedicated I would remake the flywheel but...

Alan Haisley · « **Reply #50 on:** July 25, 2013, 01:46:23 AM »

Jan,
Any idea what kind of steel you found to make the flywheel? It sounds like something pretty hard to work.
Alan

ProdEng · « **Reply #51 on:** July 25, 2013, 11:19:35 AM »

Alan, the steel was a bit of hot rolled plate and was on the soft and stringy side. It didn't turn very nicely either. Normally I source quality material but this was a lapse in judgment on my part, my original plan to fabricate the flywheel would have been better as it involved brass.

ProdEng · « **Reply #52 on:** July 28, 2013, 09:04:01 AM »

A little more done this weekend, the piston and piston rod. No pictures of the piston being made because I forgot

The piston was made from a piece of cast iron rod to fit into the aluminium cylinder. I tried to make the rod from stainless and while it turned well enough I couldn't get a thread on it, just too stringy. Plan B was to use a piece of less than ideal silver steel as nothing else of the right size was available. That went better but again the threading was not so good. The thread was screw cut and then cleaned up with a die nut.

The good news is that the piston goes up and down without hitting either cover

Not many parts left to make now but lots of fitting and finishing followed by some paint maybe. Time to start thinking about a new project!

Don1966 · « **Reply #53 on:** July 28, 2013, 02:36:49 PM »

Jan, that is going to be a nice engine. I find small rods don't thread very well on my lathe either. I just do as you did, follow up with a die.

Don

ProdEng · « **Reply #54 on:** July 29, 2013, 12:00:38 PM »

Don, my theory is if I attempt to screw cut everything, eventually I will get it all just so and the die will sit in the draw. I need to make a jig to grind the tool a little more accurately, with pitches down to 0.35mm (72 TPI) the tool needs to be spot on.

ProdEng · « **Reply #55 on:** August 11, 2013, 05:33:09 AM »

With the graver rest finished it was time to get on with tidying the studs. It takes on a few seconds to chamfer and radius the end of the stud; it takes longer to mount them to the chuck than to turn them! The stud is screwed into the bar in the chuck and this proved to be a poor way of holding the stud due to random and excessive runout. I need a better method for stud and nut making

The stud in the picture is M2 and the graver is 1/8" HSS.

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Author Topic: A Small Inverted Vertical Steam Engine (Read 27397 times)

Arbalest