As always, Mr. Best gives good advice and I've used similar techniques to establish square on other machines too, the only thing I do differently is wrap the square around the front so it's riding against the face of the fence (where the stock will be) and I don't have to rely on the front of the fence being parallel to the back of the fence. ?The fence on the slider needs to be exactly square to the line of travel in order to get shoulders square to the work piece. ?If you are using a bump stop, or another form of stop, then the component being machined needs to be prepared properly but I still always try to make sure I use the same portion of every component up against the stop. ?Some folks will tenon one end and then use the shoulder from the first one against a stop to make sure the shoulder to shoulder lengths are always identical, just depends on what you're after and how you want to work.
