|I wanted to share a few thoughts on speedy vise alignment.|
For 100% accuracy, there is no substitute for indicating in a vise. For everything else, there's cheating!
Yes, this is a cheap Harbor Freight drill press vise. No, it is not as precise as a real milling machine vise. But if you understand its limitations, it can be very useful. It will do for this demonstration.
In the above photo the vise is canted at an exaggerated angle to show what we are trying to eliminate.
If you put a steel rule in the vise as shown, it is easier to see the angle, especially if you look straight down on the T slots. This is a small vise with a 6" rule, but the longer the rule, the more accurate your guesstimate will be.
In the photo below, it is easy to see the vise is much straighter. But not quite there, yet. Sorry for the flash glare.
In this photo, the vise is straight enough for all but the most picky milling jobs. If the job is that critical, either run an indicator on the edge of the rule or cut soft jaws.
With a 12" rule, I can get a vise to one or two thousanths in 12" by eye. With a little practice, you can too. The whole trick is to look as straight down as you can and compare the edge of the rule to a T slot.