Lathe Project 1 - Simplex Air Engine

I wanted to share this Simplex Engine design.  So I have created one large (and maybe slightly overwhelming) drawing to aid anyone else who wants to build it.

Please remember, I have not yet made every part, so there may be mistakes and/or missing dimensions.

Simplex Engine Drawing

Lathe Project 1 - Simplex Air Engine

Over the past week, I have been using every spare night to machine my engine parts.  Here is what I have done so far.

First, I re-machined the piston to cam connecting shaft.  I was not happy with the first version. After my third attempt, I'm pretty happy with the result.  A few mill operations and it's done. (the top part is the first attempt, the bottom my final part awaiting machining on the mill).

Connecting Rods (my iterations)

Next, after only one attempt, I created a nice drive shaft which also serves as the valve for this engine.  A few mill operations and it's done.

Drive Shaft

Next, I machined the pin which will hold the Connecting Rod to the Piston.  I just need to thread the small diameter (#2-56).

Piston Pin

Finally, after a number of failed attempts, I finished the lathe work on the Cam Shaft Pin.  This pin connects the Connecting Rod to the offset weight.  Two of the diameters need to be threaded with #2-56.

Cam Shaft Pin

I have also included two cross sectional images of the engine assembly.  The first image is the cylinder being pressurized (the compressed air comes from the end of the tube).

Pressurize Stroke

The next image shows the exhaust stroke.

Exhaust Stroke

Lathe Project 1 - Simplex Air Engine

For my first 'real' project, I wanted to start small.  Nothing too time consuming or complicated.  After poking around on the web for a while, I stumbled on a 9x20 lathe blog (Smithy's Lathe Blog).  Smithy has made a number of cool working engines powered using compressed air.  After doing some reading, I thought I could do the same.  So, I sat down and designed my own based on Smitty's.

Simplex Air Engine - Front

Simplex Air Engine - Rear

I have also started the first part, the connecting rod.  The basic shape is there, next comes a few milling cuts and then holes for the pins into the piston and cam.

Partially Complete Connecting Rod