It obviously wouldn't work on more industrial sized machine tools where the sizes, weights or design complexity prevents it or takes too long to do. For the smaller and more simple machine designs like his Myford, George Thomas advocated in one of his books of pulling the cross and top slide feed screws and adjusting the gib until the slide can be smoothly pushed by hand from end to end without a trace of going tight or slack. That's also not going to work with a whole lot of wear if that's present. But this is a machine tool rebuilding forum.
To me doing it that way is a lot more sensitive. But also double checking for any excessive side to side clearance with an indicator as eKretz mentioned is my method as well.
To me those tapered gibs are imo the first sign of being a decently designed machine and it's what my BP clone has. A whole lot of older/smaller machines had or have the much poorer set screw adjusted non tapered gibs. So fwiw maybe I can add something here because oddly I've never once seen it mentioned in any forum post yet that this type of gib design has a major and built in fault. G. Thomas explained and illustrated the problem extremely well and how to properly fix it. As he said, the general adjustment method would be just fine if the slide didn't ever have to move, since it does and the instant the slide is moved, then due to friction between the parts, it then tries to drag the gib in whichever direction the slide is moving. And those pointed in most cases gib screws and the divots they seat into on the gib work exactly like miniature wedges that then help to tighten and ruin even the best set adjustments. Once that gib rides up enough on the slope of the screw tips it over rides that frictional drag and it's then held in place but still tightens up those carefully set adjustment clearances. Because of that, the gib adjustments need to be run a bit looser than ideal. No it's not much movement, maybe less than a thou, but it can and does affect how much feed screw pressure it takes to move the slide as well as giving the slide a certain amount of stick/slip and logically a bit more part wear.
How he solved the problem was with a simple cross pin and a hole drilled through the side of the slide and just through the gibs depth while the parts were fully assembled and in there working position. Then he disassembled and re-drilled the hole in the side of the slide to be a close slip fit on the pin. The hole in the gib was left as a light press fit. Then he drove the properly measured for length pin into but not past the other side of the gibs face. That pins the gib in place and prevents it from trying to move with the slide at all. Yet the few 10ths or so of clearance allows removing the parts during any future disassembly. Yes I've done it and it does exactly what he says it will. On larger machines than his Myford, reaming the two different sizes instead of only drilling them might be the better method though. Those tapered gibs also solves the same problem if it has the two opposing screws to lock the gib from moving.
