The pointer is a
very rough guide, they're marked with the accuracy of a 5 dollar protractor. And you can set your marks with the same protractor on the slide. Some of the better taper attachments have a vernier scale, but you still have to rely one something a little more accurate for really bang on tapers, since those vernier scales are marked in 5 minutes of an angle.
If you want to do your own morse taper shanks where 100 percent contact is critical. You use a dial indicator over a one inch travel (2 inches is better if you get the long travel ones) or your DRO. You have another dial set up on your cross slide to measure how far it moves. Its realy critical that you get it pretty darn close with self holding tapers like the morse tapers. The difference in a few thou per inch in taper will make the difference between a good self holding taper and a lawn dart.
Im going to assume your using the old style taper attachment and not the telescoping type, because you have to rid the backlash on the telescoping.
I dont remember what the morse taper angle is off hand but I will do an example with pipe thread for you NPT with an angle of one degree and 47 minutes. or 3/4 of an inch per foot, to get an angle from a taper ratio its tan-1(rise/run) or tan-1(amount cross slide moves/amount carriage travel)
NPT tapers 3/4 inch per foot in diameter, which means your diameter increases by .75 an inch for every 12 inches in travel.
.75 divided by 12 will give you how much your diameter increases in one inch, and this translates into
HALF THAT DISTANCE your cross slide will travel in one inch.
.75/12=.0625 This is your diameter taper per one inch
(.75/12)/2=0.03125 This is your radius taper per one inch
In english, you alter the angle of your taper attachment bit by bit until you get to the point were when you move your carriage one inch, your cross slide will move 0.03125. you can then mark your ratio of angle on the attachment regardless of its distance of the pointer from the pivot length. You place dial indicater with the plunger contacting the carriage, with the magnet on the ways to measure how far the carriage is moving (in this case one inch) and you place the other dial with the plunger on the cross slide, with the magnet on the cross slide ways to measure how far your cross slide moves (in this case 0.03125)
heres the morse taper angles I just dug up, give it a try.
http://www.diracdelta.co.uk/science/...er/source.html