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Tag: memory loss

Timing the Trevithick dredger engine-3. How embarrassing….

As planned I removed the engine from the boiler, to discover why it would not work with compressed air yesterday.


After yesterday’s failed attempt with compressed air, I removed the cylinder and piston and valve assembly from the boiler to check the steam passages, throttle and rotary valve. 


These components were removed so I could see what was going on.

I wish that I had checked this before going into print yesterday.

I discovered that the bronze cylindrical insert with the steam ports had never been fixed/Loctited into position.  Clearly it had rotated with the first engine movements yesterday, causing all steam passages to be blocked.  No wonder I couldn’t get the engine to do anything!

And worst was that I had mentally made a note to secure the insert, when I inserted it, a month or so ago.

So today I drilled and tapped a hole for a stainless steel grub screw to hold the insert into position.  I decided not to Loctite it at this time, but will do so when I am sure that the timing is correct.  I might need to alter the shape of the ports, and the insert would need to be removed to do that.


Tapping the thread for the grub screw using the shop built tapping head which I made to Mogen Kilde’s design a couple of years ago.  I have never broken a tap while using this tool.

After reassembling the components I ran another test with compressed air.

Somewhat to my surprise, at 20psi the engine ran for a few revolutions, before  settling down into a back and forth motion.  It still needs to be timed, but hey, it moves.  But by this time it was becoming hot in the workshop, so I left the timing for another day.  Maybe tomorrow pm.   Not Thursday because it will be HOT.  42ºc  (107.6ºf)


Anyone for a swim?

High summer.

Hot workshop, wearing only shorts and boots.


I think that I will stay in the workshop.

Today was my deadline to have the triple expansion steam engine assembled and working, ready to be hooked up to steam at the Geelong Truck show.

GSMEE (Geelong Society of Model and Experimental Engineers) has a display in the Vintage Machinery Shed at the show, with many small working steam engines and the odd IC engine running.  Plus the Vintage Engine group has many full size engines running….  always a really interesting place to visit.

Another full day in the workshop would have just about had the triple in the display.  Unfortunately, I lost a day having to get a dental root canal abcess reamed out.

Then the day before yesterday, I could not find the drag links for my triple.   I had made them in early December,  and I was sure that I had put them in the multi- compartmented box where I store all such bits.  Despite thoroughly searching the box, at least 20 times, they were not there.  Could I have put them down somewhere else in the workshop?  So I searched the workshop.  No luck.  So I tidied the workshop, putting tools away, sweeping up rubbish, all the while searching.  Still no luck.   So I cleaned and searched my car, my bedroom, the living room, every where that I could concievably have left them.  (OK, I did not actually clean the bedroom and living room, but I did search).   I grilled my wife.  Had she seen them?  No.

So I slept on the problem.  Next day was going to be hot, so at 7am I drove to the workshop (it is about 15km from home), and searched again.   Still no luck.

So I searched the multi compartmented box for the 21st time.  I knew that it was a waste of time, but I was seriously considering making a new lot of drag links and bearings, probably a 2 day task.

There were some tiny containers with tiny fasteners in the compartmented box.  The drag links could not be them because they are too big, aren’t they…..??

The first tiny container, contained, you guessed it, the drag links.!!  They were smaller than I remembered.


Self disgust!

Age related loss of short term memory…..

I had to get that one off my chest.

The other thing that I wanted to mention, is a superb machining blog site.  Actually, 2 superb machining blog sites.

The first is by Joe Pieczynski, who is a Texan who makes his living from machining.  His techniques and teaching are really, very, excellent.  Aimed mainly at an audience who are beyond absolute beginners.  Do a Youtube search on “Joe Pieczynski”.  Look at his video on machining ultrathin materials.

The second, I have probably mentioned before.  An Australian  machinist, whose videos and machining techniques have to be seen to be believed.  Mainly with a clock making interest, but the techniques can be used by all of us.  For some reason I cannot cut and paste his Youtube connection, but you will find it by doing a search on “Clickspring”.  What is particularly exciting in Chris’s “Clicksping” is that he is soon to embark on remaking an Antikythera calculator.  Watch it!  You will be hooked.






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