I’ve got one, and I’ve used it typically where I’ve needed to cut some ply to fit in house improvement work. In this sort of situation it works well. Find the angle by slapping it against the place where the cut piece should fit. A firm twist of the knob to fix the angle. This is accomplished without any tendency to change the angle. Then put then angle guide in the guide rail and gently push the angle guide against the work. However, from this point, do not use the angle guide as a fix for the guide rails. The guide rail should now be in the correct position so use the guide rail just as you would if you had placed it against a drawn line. This means you would either clamp the guide before cutting, or, if the cut is not too long and the guide is gripping the surface, then in the normal fashion you can use the guide rail trust that the rail will not move. I often find I can use the guide rail without clamping, but if the cut is a bit awkward then its all to easy to move it a tiddly bit even for ‘normal’ cuts if one has to move ones body to continue the cut and perhaps even un-plunging and re-plunging the saw for one cut. So for any cut where I’m not square to the rail and I cant put one paw on the guide rail then I find its best to clamp firmly first. And angled cuts fall usually fall into this category for me. But then I don’t do this for a living and skilled hands would be better at this I would think.
