I live in a camper van with a West Highland Terrier for company.
My passion is creating images but it is a work in progress.
I am always willing to share what knowledge I have and can be contacted through the comments on this post or e-mail ADRIAN

Tuesday, 2 November 2021


 I was awake long before the Lark this morning and after an espresso was raring to go at the crack of four. I couldn't face learning the Assembly Workbench in FreeCAD so decided to model another version of the cylinder head. I got there after a couple of hiccups but the model is no good. I had a big topology problem which is something that happens far too often in FreeCAD. I know the answer is not to put sketches on model faces, one should instead attach a Datum plane and sketch on that. The model needs doing again so I'll be more considerate of my workflow next time.

This looks okay but will cause problems if converted to a line drawing/blueprint. It would be impossible to convert to machine code.

This measures 32mm x 15mm, the groove is for a silicon "O" ring to seal the glass cylinder, it doesn't need to be a groove so in the next version I'll make the minor radius of the hemispherical combustion chamber larger.
I then lost two hours of my life. I found the formula for calculating the volume of the hemispherical section and then very vaguely remembered having to generate this during calculus at school. That's all I could remember so I foolishly searched for the derivation on YouTube. As is always the case I had a couple of false starts then found this chap who explained the matter perfectly.
This was fun and he got the correct result which is more than I did all those years ago. Clever bugger he is. Looking at his white board a scruffy clever bugger.

If I manage to complete this project, I'll either be very happy or totally insane. I'll leave you with this.

Have fun.



  1. Okay. I had to go back this far anyway now that you are blogging again. Love the cartoon.Your understanding of all these things is so far ahead of mine that I might as well be on a different planet.

    1. I enjoy it Graham. I have barely scratched the surface if you'll excuse the pun.