This is the tool as designed in England by George Thomas and described in his book Workshop Techniques. The standard reach set of castings follow his dimensions.
This tool was designed by George H. Thomas (GHT) and first described in a rather disjointed sequence of articles that appeared in the Model Engineer in the mid-1970's. All of these were later collected into a book titled "Building The Universal Pillar Tool". After being out of print for some years, it was combined with material describing GHT's Universal Dividing Head and printed as "Workshop Techniques". This is not a word-for-word reprint of the previous two books; it also contains additional useful material. The castings and the book are in one place.