Author Topic: A Small Inverted Vertical Steam Engine  (Read 26909 times)

Offline ProdEng

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Re: A Small Inverted Vertical Steam Engine
« 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 :Mad:  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 :Lol: 
Jan in Perth

Offline b.lindsey

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Re: A Small Inverted Vertical Steam Engine
« 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

Offline ProdEng

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Re: A Small Inverted Vertical Steam Engine
« 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.
Jan in Perth

Online Dave Otto

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Re: A Small Inverted Vertical Steam Engine
« 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

Offline ProdEng

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Re: A Small Inverted Vertical Steam Engine
« 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...
Jan in Perth

Offline Alan Haisley

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Re: A Small Inverted Vertical Steam Engine
« 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

Offline ProdEng

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Re: A Small Inverted Vertical Steam Engine
« 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.
Jan in Perth

Offline ProdEng

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Re: A Small Inverted Vertical Steam Engine
« 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  :embarassed:  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 :cartwheel:



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!
Jan in Perth

Offline Don1966

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Re: A Small Inverted Vertical Steam Engine
« 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

Offline ProdEng

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Re: A Small Inverted Vertical Steam Engine
« 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.
Jan in Perth

Offline ProdEng

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Re: A Small Inverted Vertical Steam Engine
« 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 :embarassed: The stud in the picture is M2 and the graver is 1/8" HSS.

Jan in Perth

 

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