Hi, Thank you for your answers. The steam engine we are building is from the book " Things to make " by Archibald Williams. This is an old book from the beginning of the XX th century. You can have a look at this design in the Project Gutenberg Ebooks on the web. For sure it needs some modifications..... PIerre MODEL ENGINEERING DISCUSSION LIST. To UNSUBSCRIBE from this list, send a blank email to, modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject line.