Just to give you some idea of what can be done without special tools but with lots of care. One of our local members, who earned a living from rebuilding classic racing cars and old motorcycles, bought an ex-Argentinian twin and set about checking it out. Using only straight edges, set squares, clamps and the kind of measuring equipment we almost all have, he found that the inner faces of the rear frame lugs, which take the rear wheel spindle, were not parallel when clamped up to the correct width. Frankly I have never even thought to check that measurement. Fortunately he had the skills and equipment to mill the two inner faces back to parallel. Ingenuity and care can replace a lot of high tech. The device shown in David’s video is a treat to watch but my guess is that it cost a fortune and requires a lot of training and practice to make best use of it.