Old thread but same type problem.....

Good old 4.500" TPF.

I'm trying to get my head around what it actually means and how do I make it meaningfull:

1) Aproximate angle in degrees to make rough check (included angle)

2) Exact numbers to make the taper in the lathe (top slide method = half angle)

So, this is the bugger: 4.500" TPF big end is 0.87"

http://www.wmsopko.com/images/D-00108-R.jpgGreat. I assume that 4.500" TPF stands here for included angle, which ratio is 4,5" for 12,0" and half angle would be 2,25" displacement at 12" distance? Is this correct and if not what actually then this 4.500" TPF stand for and what it is when setting the machine to do this taper?

I think I know but after reading this thread and being raised on ratios of half angle I am having this WTxxxx moment.

Pekka