MichaelI can post a drawing for the design that I made the short run of. The design is pretty basic but the most important attribute is the ability to set up precise clamping situations.
Michael
Thank you Michael,I had to sort out a couple of things and add some dimensions these are general and there is a lot of scope for variations the principles are what are important. I have saved the drawing as an autocad DXF a JPG and a PDF
View attachment 216082
I hope this helps, I also have lots of photos of various types of additional clamps that slide into the top 3/16 hole. I used National Fine and Coarse threads, but these are arbitrary metric or BA equivalents would obviously work equally well \.
Michael
I can see a number of us building them going forwards.Thank you for that. Looks like a project for the Autumn.