Bill Tindall, E.Tn.
It is the home stretch when it gets to be time to install hinges. I find this operation stressful. A screw up here will be apparent to all and some are not possible to fix.
What I do is common in many shops. I number the hinges, having been burned by a batch of hinges being slightly different in the past. I lay the hinge where it will live and scribe the ends on the door stile. With a marking gauge set to just shy of half the hinge width I scribe the width of the mortise.
With a router set to the hinge thickness I free hand route away as much waste as I can, almost kissing the scribe lines. Another of the many things I learned in the Headley shop was the value of being proficient at free hand "carving" with a router for waste removal.
Shown is the cobbled together arrangement I have for holding long things in the vise I have. It works. I would like to know what others use that could be better, or more convenient.
It is then a simple matter of chiseling away the waste in the corners.
A hinge is temporarily installed with one steel screw, shorter than the final brass screw. When the door fits to my satisfaction I will come back and install all the brass screws. By installing screws one at a time I have the opportunity to diddle with screw holes to ensure the hinge is snugged against the mortise. If one of the three screws wants to pull the hinge away from the mortise and I can't fix the situation, I will just leave it loose. If the mortise is made correctly it will be the mortise than holds the weight of the door and the screws merely hold the hinge in the mortise. One snug screw is sufficient for the task.
Two dimes are set where the bottom of the door will close (the final clearance for the bottom of the door) and the door wedged into position. The hinge positions on the case stile are marked and the above process repeated for making this mortise.