machines which I have made, am making, or intend to make, and some other stuff. If you find this site interesting, please leave a comment. I read every comment and respond to most. n.b. There is a list of my first 800 posts in my post of 17 June 2021, titled "800 Posts"

Tag: John; eye surgery; metalworking


90% setup time, 10% machining.

The columns are tapered on all faces, so are difficult to hold, and difficult to measure.

I did a CAD drawing, to measure the taper angles, and to calculate some extra dimensions.

Then, in order to hold the castings in the milling vice, I made some accurate wedges at the appropriate angles (3 and 12 degrees) in wood and aluminium.

I actually progressed a bit further than the photos show, even roughing out the condensing tank.



The aluminium wedges have a 12 degree taper. The top wedge is sitting on a 10 degree and a 2 degree precision taper, giving an accurate 12 degree slope for milling. I made 2 such wedges, each 100mm long.


Unmachined casting on right. Partly machined on left. Quite difficult to set up, despite the setp up blocks at the appropriate angles.


Today I received a 16.6kg package by courier. It was too heavy for the regular post.  It contained the castings for the model triple expansion steam engine, which I am hoping to build in the next year or so.  I am told that on average this model takes 3000 hours to complete.  That is a scary thought.  Almost unbelievable.  But when I calculate how many hours went into the much simpler single cylinder beam engine (maybe 600-800), I guess that it is not an unrealistic estimate.  Just as well that I am close to retirement age.

The castings were made in NSW Australia, and supplied by Kelly Mayberry at EJ Winter.

All carefully wrapped

All carefully wrapped

The castings are all brass, gunmetal, or bronze

The castings are all brass or gunmetal.  There must be at least 100 of them.

Looks like the condensor chamber, as part of the engine frame.

Looks like the condensor chamber, as part of the engine frame.

The base.

The base.

A large chunk of brass

A large chunk of brass, the intermediate and low pressure cylinders.

The castings appear to be free of holes or defects

The castings appear to be free of holes or defects


As you can see from the picture, the Ridders “bobber” is quite a pretty engine.
If it works perfectly it develops just enough power to revolve, but not enough to do any work or to overcome any perceptible internal friction.
Unfortunately, my Ridders does not even turn over with the heat applied. It revolves freely by hand, so I do not see where the problem is. In any case, now that I know how powerless these machines are, I have lost interest in spending more time on it, and I am returning to paint and finish the beam engine.
The pictures are for interest only.

(ps.  Note made April 2017.   About a year after I originally posted this, I returned to the Bobber.  I made a new piston from graphite, replaced the 3 steel balls with ceramic balls and retried it.   It still did not work.  Then I tried varying the number of ceramic balls.   With 2 balls, it ran perfectly!   Smooth and fast.  There is a video of the feat in a later post.)

This is the first engine which I have made which does not function.

Almost fully machined Ridder “bobber” heat engine.
With heat applied.
Unfortunately it does not work.



Or something like that…

Last year, when climbing out of the gorge of the Zambesi River, Zimbabwe, I developed an enlarging black spot in my right eye. The black spot progressively enlarged, and I decided that I had contracted one of those African worms which eats its way into the human central nervous system.  So of course I ignored it, and flew home to Oz.

Over the next few days, the black spot became bigger, blocking out about 1/3 of the vision in my right eye.  So I thought, this is not normal, and I consulted an eye doctor.

One hour later I was having an emergency operation for a detached retina.

The eye doctor sucked the fluid out of my eye, filled it with gas, and lasered the retina back to where it should be.  All under local anaesthetic.  A painless but weird experience.  I was totally blind in my right eye for 2 weeks, then miraculously, my sight returned.   Gradually, from the top down, as the eye refilled with fluid.  It was really odd seeing a water level upside down.   Like seeing the sea above the sky.

At least my left eye was OK, but I really got to appreciate the value of binocular vision.  It really sucks when you pour yourself a nice red, only to miss the glass.   And machining is a challenge.

To cut a long story short, my sight was restored thanks to modern science and first world medicine, for which I am profoundly thankful.  Also to Drs Ben Clark,  Patrick Lockie, both expert and dedicated Australian eye doctors.

One year later, I have had another eye operation, this time to replace the right lens, because I had developed a rapidly deteriorating right cataract.  Again under local anaesthetic, again expertly performed, this time by Dr Mark Whiting.   My vision is a bit blurred, and I need new glasses, but must wait 4 weeks.  Meanwhile, I must not work (as a surgeon), and other activities are hit and miss.  Already I am having withdrawal symptoms from my workshop.   Maybe the electroplating would be OK, if I can persuade SWMBO to drive me to my workshop…..