I have a TG jig built from just 2 castings, one of my round to its. Got the sketches from Canada, Guy Lautard and given the castings by someone who had given up, probably because he had no drawings. So started from scratch a long time ago and it's nearly finished. Just got the tool holder block to bore, drill and tap. Not top of my list as other small projects more pressing, needed for use soon and to keep the write ups going in club newsletter.
The Lautard device is very simple, based upon only one pattern to make 2 castings which need to be machined slightly differently. He goes on to describe different attachments, with necessary drawings included, to sharpen reamers, radius grinding and several others.