Elmer's Standby derivative, my 2nd engine

[bent]

Well, I haven't been slacking over the last few weeks.  Really, I haven't.  I have been slowly turning out parts for a version of the #19 engine from Elmer's plans (downloaded from http://www.john-tom.com/html/ElmersEngines.html).  My tweaks were intended to make it perform a bit better than his description at low pressures, we'll see how well that works.  I pushed the flywheel diameter upwards to 1-3/4", thinking a bit more inertia will help the motor keep ticking over in spite of the tiny and long flow passages in the design, which is "valved" through the crankshaft.  I also pushed the crankshaft diameter up to 1/4", which allowed the ports to be .090-ish instead of the 1/16" of the original design.  This meant I also had to push the stand a bit taller, and make the base a bit wider to accomodate the larger flywheel.

Photos below -

first is a shot of the base and stand squared blanks (all polished with the little sanding disk and sitting on my assembly drawing - an experiment to see if I could make a "machined turned" hotrod finish),
second is the base and stand finished, along with turned but not milled piston, bearing, flywheel and a squared bar for the cylinder.
third is the crankshaft, bearing (2nd try after mungling the tapped 10-40 inlet hole ) and blank for the crank.  Notice the step in the crankshaft, where I corrected the diameter after finding over .005 of runout.  One of my next projects is tearing into my mini-lathe tailstock to make it easier to adjust the center.  Grr...    I've seen some stuff on the interwebz about doing this...but it doesn't look easy.  Sigh.
fourth is a picture of the piston rod blank (1/4 x 1/8 flat bar) setup to run in the 4-jaw chuck, and the cross slide set to turn a 3 degree taper.  I struggled with alignment (stupid tailstock...grrr... ) but finally got it to about .005 runout (ish).  Add another project -make a toolpost holder for the dial indicator.  Oh, and then junk the cheap, and now slipping Hazard Fraught adjustable holder.
fifth and last thing on Sunday was turning the piston rod, very slowly (500 rpm and .005" max cuts) to avoid the worst of the chatter.  And then resetting halfway through when the cross slide started to knock against the live center in the tailstock.  Oh, and again when some idjit bumped the carriage wheel.  And then the moment of panic when I re-adjusted the tailstock and it looked like I'd buckled the part     -but it was just the lens distortion of the new headset magnifier I was using.  Whew.  Turned out ok, even if it isn't perfectly symmetric due to the runout.

Now to find time over this coming week to use the mill/drill here at work, and hopefully not mangle anything else.  Wish me luck.

[Ye-Ole Steam Dude]

Parts are looking good and the changes you are making should improve on the performance.

[bent]

Ok, just about done.

In order of photos below
(1) Turned the crankshaft, bearing and crank pieces
(2) Bored the cylinder on the lathe with 4-jaw chuck (this got a little bit tapered, using a fairly slender boring bar, had to hone it a bit afterwards).  Then to work, to bore and tap #3-48 mounting holes (not too deep!).  Drilled and tapped #10-40 for the steam/air inlet on the bearing.  Pressed the bearing to the stand with a little bit of green loctite, and drilled the (.098 dia.) port thru the bearing wall. 
(3) Milled the "valve" flats on the crankshaft - note I turned a groove that aligns under the bearing inlet port, so I wouldn't need to align the inlet with anything else, I just located it where I wanted it.
(4) Crank "valve" flats milled, and
(5) machined a very small .125 od x .100 id bearing for the #3-48 cap screw (I didn't think I could make a go of machining a #3-48 shoulder screw like Elmer did, so this was my substitute).

Now home to make a plug for the flow passage, turn and thread an inlet tube, do some final deburring/polishing and then assemble.  Hopefully post a video tomorrow.

[Ye-Ole Steam Dude]

All that work really looks good.

[b.lindsey]

Very nice. Looking forward to the first run 

Bill

[90LX_Notch]

It is coming along nicely bent.

-Bob

[bent]

Thanks again everybody.  It's been fun, even if only to learn more about how to be a more precise machinist (starting by reworking some bits of my mini-lathe, and seriously thinking about buying a decent mill that I can mod to be the way I want it, and leave setups in it, and ...etc.).

Here are some of the last photos of the assembly process, and a link to a video of the final build running.  There is a slight air leak at the inlet tube where it threads to the bearing; just not enough meat there to make a good connection I guess.  Should have stuck with Elmer's soldered joint  .  Oh well.  Runs ok, if a little sticky at first, and throttles down to about 4.5 psi where it's just barely ticking over.

running video:
[youtube1]https://youtu.be/1qe2zbbEY9Q[/youtube1]

photos below,
(1) setting the "valve" timing using a .093 drill bit to center the "exhaust" port at mid-stroke for the crank
(2) completed assembly
(3) tapped the flow passage in the stand to thread in a piece of a #3-48 screw, which then got a liberal application of thread sealant

And now back to redrawing one of Jan Ridder's glass-cylinder "Flame Eater" plan sets for American standard units, and to fit materials I could find...

[b.lindsey]

Looks and runs great! The engine turning in the cylinder and base add to the finished look too!! Well done.

Bill

[Ye-Ole Steam Dude]

Bent your engine turned out great and it is a running little jenny.

[bent]

Umm, just realized I posted video here in the build forum instead of the "showcase"  .  I assume it's ok though?

[b.lindsey]

It's fine also if you post it in both places.

Bill