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"

Category: KoffieKop

Koffiekop Modification

I have been considering this modification for some time, and today I located the aluminium heat sink-radiator material which I needed, and which I knew was somewhere in my stuff.

The Koffiekop Sirling engine requires differential temperatures between the top and bottom plates.  I wondered if installing some heat shedding plates on the top plate might increase the running time on a cup of coffee.


The heat sink material is glued to the top plate with a heat transmitting electronic silicone glue.

Afterwards I ran a test with a cup of hot water.

The engine ran for 26 minutes!  That is an improvement of about 25% on the best previous runs.  Success!

The Horizontal Mill Engine (HME) is assembled and ready for the D valve to be timed.  This is how it looks.  I wont get to it for a couple of weeks now.


I did squirt some compressed air into the valve chest, but minimal movement.  Not surprising, considering the position of the eccentric was just a guess.  When I get it going there will be a video.  That crankshaft pin is temporary.  It is a 3mm cap screw going through a 4mm cap screw.  go figure.


Flywheel and Sugru

Firstly the SUGRU update.

Sugru, if you have been following this blog, is the flexible black insulating repair compound which I used to repair some electric cables on my lathe.   The cables supply power to the stepper motors, so they are in constant flexing motion when the lathe is operating.  I wondered whether the Sugru would remain adherent and intact.

Well, I am pleased to report that after several weeks use, the Sugru looks as good as the day I applied it.  A winner!

The flywheel.

This is the flywheel after some sanding and polishing with a Dremel.


The 100mm flywheel, with lubricant ready to be applied.

I might have to make another Stirling engine to use it.