Hi Pierre,
Some really good Unimat articles by Rex Tingley and others can be found in the Model Mechanics magazine. These include various bits of tooling, and even the complete build series for the "Sweet Sixteen" 16mmm to the foot traction engine built on the Unimat.
The good news is that the magazines are free to download from this website.
To do so, hover over FEATURES in the black toolbar near the top of the page, and then click on Magazine Reprints. You will find the list of Model Mechanics magazine ready to download at the bottom of the second page.
Clive