Plans, projects and how-to's for home machinists

A couple of “micro” Stirlings

This is Jan Ridders’ newest Stirling engine.  It’s so small it uses a 1 Euro coin for the flywheel and a couple of 5 Euro cent pieces for the top and bottom plates of the displacer cylinder.   Jan will tell you that he got the idea for building a micro- engine from a Swiss artist who goes by the name “jovallmen” on YouTube.  His engine uses a couple of Swiss 5 centime coins and it may be even smaller than Jan’s.  You can see a video of it here.

As usual, you can get a set of free CAD drawings for this engine by visiting Jan’s web site and requesting a copy.

Jan Ridders’ Updated Flame Eater and “Scuderi” 4-stroke Engine Plans

Jan Ridders has updated plans on his web site for two of his favorite engines: a 2-cylinder flame eater and a Scuderi Split Cylinder internal combustion engine.The flame eater was one of the first engines that Jan drew up detailed plans for and one that has received a lot of interest since he first made it eight years ago.  He said the quality of these original plans was poor and in his spare time has updated the CAD drawings to make them clearer.  It was a project Jan said he almost scrapped because at the time he didn’t know much about what it took to get flame-eaters to run, but after building a vertical 1-cylinder engine he got the hang of it and picked this project up again.

The Scuderi Split Cylinder engine was another of Jan’s favorites, but after the plans raised design questions he decided to update the CAD drawings.  Jan found plans for it on the internet and then made some variations, like separating the two cylinders entirely. This is easy to make using mostly standard parts.

Jan features a number of other engines on his web site, which is available in both English and Dutch.  You can request a copy of his plans by sending him an email.

Jan Ridders’ Flame Eater “Marc”

Jan Ridders recently updated his plans for a vertical flame eater engine that he originally made in 2003 as a birthday present for his son Marc.  He made a number of improvements and redrew the plans using a CAD program.  Jan says this engine is “more forceful and noisy” than his Stirling engine models.

This is just one of about two dozen beautiful engines Jan has designed.  You can see them all by visiting his web site, which is in both English and Dutch (look for the buttons to change the language).   Jan gives his plans away for free, although he will accept a donation if you’d like to make one.  You just have to send him an email telling him which plans you would like.  You can contact him via his web site.

Materials List for Jan Ridders’ Simple LTD Stirling Engine

Here is a list of the materials you will need to build Jan Ridders‘ new simple low temperature differential Stirling Engine.  You can download the plans here (PDF).

I was going to build his Coffee Cup Stirling but I have started building this one instead because it will take a lot less time.  I have not been able to spend much time in my workshop lately, which is typical during the warm weather months, and I would like start a project I can finish within a reasonable amount of time.

I know I get a lot of visitors looking for information about Jan’s Stirling engines, so I am posting this with the hope that someone will find it useful.  I usually hate studying plans to determine what materials and tooling I’ll need to buy.  I’m always worried I’m going to miss something and the project will grind to a halt while I place an order and pay a huge shipping fee for just one item.  I’m not too fond of ordering stuff either.

Fortunately, I already have almost everything I will need.  I just have to buy the graphite, a glass tube for the power piston cylinder and a suitable plastic tube for the displacement cylinder.  I did some checking last week and I think the glass and graphite will be easy to obtain.  Finding a 4-inch clear plastic tube has been a problem.  You really can’t make the top and bottom plates until you know dimensions of your tube.

Jan’s plans are in Metric units and I’m in the US, so I am going to have to convert them to English units.  I have not built this engine yet, so consider the fractional English sizes I listed to be just suggestions for now.  Stayed tuned because I’ll start posting some construction photos and notes soon.


  • 18 mm [.70 ~ 11/16-inch] round – Countra weight (Counterweight) – Sheet 6
  • 20 mm [.78 ~ 3/4-inch] round – Displacer kernel (Hub) – Sheet 5
  • 32 mm [1.26 ~ 1-1/4-inch] round – CD kernal (Hub) – Sheet 6
  • Material to make two 112 mm [4.41-inch] diameter disks for the top and bottom plates of the displacement cylinder.  One needs to be 5 mm [.20-inch] thick and the other 8 mm [.31-inch] thick.

You have a couple of options here.  One is to start with a couple of disks cut from a 112 mm or bigger round bar.  This could be very expensive if you have to buy a length of it.

A cheaper alternative is to make them out of a flat plate by following Bogstandard’s excellent tutorial.  You also have some choices if you do it this way.  You can buy your aluminum plates in the two thicknesses you’ll need or use the same thickness for both cylinder plates, which should look and work fine.  You can also mill the metal down to the thicknesses you’ll need.


  • 5 mm [.20 ~ 3/16-inch] round – Fork (2) – Sheets 5 & 6
  • 11 mm [.43 ~ 7/16-inch] round – Crank webs (4) – Sheet 7
  • 1 mm thick x 6 mm wide flat stock [.04 x .24 ~ 1/32 x 1/4-inch] – Displacer & Piston Rods – Sheets 5 & 6

Continue reading Materials List for Jan Ridders’ Simple LTD Stirling Engine

Random Quote

Ignorance per se is not nearly as dangerous as ignorance of ignorance.

— Sydney J. Harris