Engines > Your Own Design

Redo of Elmer's Standby for beginners

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This has been kicking around in my head for a long time.   I built Elmer's Standby years ago.  The rotary valve interested me.   I did not like the small scale / drills / screws / taps etc.   Always thought it would be fun on a larger scale.  Then the post about a beginner's engine got me to thinking about this again.   Drew up some quick pencil sketches at work with some rough dimensions as guide lines.

With the same approach as my past EZ Engine I wanted it simple, no mill needed, common tools, and minimum of pieces to order.   

So here we go.  Started with .75" x 2" aluminum bar and bought 4.5 inches of it.   .75" for the main shaft support.  1.5" for the cylinder and 2" for the flywheel.   Cut it into its pieces;

IMG_5888 by black85vette, on Flickr

Flywheel first.   Locate the center and center punch.   I use some cloth gaffer's tape on my chuck for added friction.   Hold it tight with the live center and then make it round;

IMG_5893 by black85vette, on Flickr

IMG_5894 by black85vette, on Flickr

Face both sides then drill the hole for the .25" shaft undersize followed by a chucking reamer.

IMG_5895 by black85vette, on Flickr

Cylinder is drilled undersize 1.25" deep followed by .5" chucking reamer.  Cylinder is .375" below the top.   Then drill a .125" hole at the very rear of the cylinder bore.

IMG_5891 by black85vette, on Flickr

Support for the crank shaft is drilled undersize followed by .25" chucking reamer.   The shaft is also .375" down from the top.   Then two .125" holes are drilled.   They need to be .25" apart and evenly spaced in from each side.   They match up with the valve.  Rerun the reamer after drilling the two holes to clean it up for the shaft.

IMG_5890 by black85vette, on Flickr

The valve is cut into the shaft.   The exaust port is .25" wide and the intake is .5" wide.   You can see the relationship to the two holes in the support piece.    The two notches are .050" deep.

IMG_5897 by black85vette, on Flickr

Drill a .125" hole in the end closest to the exhaust (shorter) notch.   Drill to the center of the notch.

IMG_5886 by black85vette, on Flickr

Then drill through the exhaust notch into the hole just drilled in the end of the shaft.

IMG_5887 by black85vette, on Flickr

I made a piston from .5" brass and .5" long.  Just turned down some on one end and made a flat at the center of the piston.   Drilled and tapped a 6-32 thread.   Made a crank from some scrap aluminum.   Used a 6-32 set screw in the end of the crank and drilled / tapped a 6-32 hole offset .375" from the shaft for the crank pin to give a stroke of .75".     Made two .125" wide spacers for the shaft to keep the flywheel and crank away from the support.

IMG_5899 by black85vette, on Flickr

Used epoxy to glue three .125" pieces of brass tubing into place and to hold the flywheel on.   Using some fuel line that is the right diameter for a snug fit on the brass tubing.   Also made some small spacers / bushings to go over the screws for the connecting rod to ride on.  They are just wide enough (.075") to allow the connecting rod to not bind when the screws are tightened.  Connecting rod was drilled just slightly larger than the bushings and was made from 2" of .25" x .125" brass.

IMG_5900 by black85vette, on Flickr

There you go.   Took me about 6  hours of shop time.   So maybe this is the One-a-day engine.  Fired up the compressor and it ran on about 2-3 lbs of air pressure.   Here is the video.  (because I know you will harass me if I don't post one)

Thats slick!
& simple, nice...


Dave Otto:
A little diversion Rick??

6 hours?!!! Augh!
That might scare off some beginners.
First time I built an engine it took me that long to convince myself I had the stock in the chuck right.  :Lol:

Nah. That'll show the beginners how easy it can be.

Nice job Rick.


--- Quote from: Dave Otto on January 30, 2013, 01:41:10 AM ---A little diversion Rick??

--- End quote ---

Yes, waiting on a couple of orders to come in.   Very relaxing to go from something that is half done in 4 months to something completed in 6 hrs. 


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