Gantry type milling attachment.

[olderdan]

Is surface grinding to square the riser block pads to centerline of post and/or threaded portions? Dissecting the photo hinted slight design alterations to work around that.

Sorry for the minimal post, I have been busy of late.
To explain a little further, the raising blocks were ground to the same dimensions as the tailstock base until a DTI mounted on the boring table clocked zero over the over the width of the blocks, this would also also take into account any wear in the bed, saddle and slide ways on a very old lathe and would match the way the lathe is.
The blocks were not milled but the V was plunge ground from solid with a form wheel, this was the start point for further work.
The base of the pillars were faced after welding using a 3 point steady and the pillars running true, the top clamp faces were trued in the same manner using a service mandrel. Using this method it was at least possible to ensure correct tramming in one direction, the other could be adjusted on the verticle slide.
As this is an attachment and not a milling machine some compromise must be accepted but it has turned out better than I had hoped for, and the blocks are still able to be used for their original purpose if the need arises.
I know where your coming from regards CNC and I have used it a lot before I retired and the results are unquestionable but these days I enjoy just winding handles.
Thanks for the interest.