I'm not the best at explaining myself through typing, so I'll try not to make this too confusing.
First you will need a shaft mounted in your lathe that is straight and true. I've used the tailstock quill for this as well.
To help you see where I going with this, move your compound at any angle, mount a indicator on the compound, touch off on the shaft and
move it along the length of the shaft (or quill). You'll obvious see indicator movement. We're going to call this movement the "X".
The distance from point A to point B on the shaft will be the "Y".
We know your taper is .0493" taper/inch, so if you had your compound set exactly at the known angle, you would see .0247" of "X" movement if you moved your compound the proper distance ( 1"+,I'll explain). The more travel you can get from your compound, the more accurate this will be.
If you could move your compound twice the distance", then obviously you would see .0493".
Because the compound movement is on a different axis of movement, it becomes the hypotenuse of a triangle, so we need to use the following formula: Square root of "A" squared plus "B" squared / A being the Y movement and B being the X movement.
So: The square root of 1 + .0006 = 1.0003
So, you would move your compound 1.0003" and see a indicator movement of .0247. Pretty minute I know, so if you can move your compound further, the X figure becomes more achievable.
Hope this makes sense.
