I completely understand the concerns of people that advise alternate methods and the reasoning makes sense when considering it. I
am left to wonder if it is a case of "beating the monkey"
**, however...
Frankly, my experiences have contradicted the admonitions. To be clear, I am not saying that the alternate methods do not work. We know that they do. What I
am saying is that after careful measurements and uses, my results do not agree with the cautions against the method. I repeatably achieve .0002" - .0003" runout up to 12" away from the chuck, and all the way back to it after grinding the jaws. Flipping parts that have been previously turned yields good results, as well. ( I actually have to do that fairly often )
Of course, I am not advocating that one not use their head. Quite the contrary. I took the time to choose the size of the radii that were ground as well as precautions against grinding dust infiltration. And, of course turned the chuck pressure down to suit the application. ( in Bill's case, it would be manually )
After having done this a few times now, I find the results very predictable and very repeatable. Also, easier and faster than other methods. So when I hear or read things like this, I have to wonder if someone has been beating the monkeys.
One of my posts is here -
http://www.practicalmachinist.com/v...red-soft-jaws-337081-post3001958/#post3001958
** - The old story goes that there is a cage of 4 monkeys. The keeper throws a banana into the middle. When a monkey reaches for it, all the monkeys are given an electric shock as a warning not to touch the banana. This continues for a while, until one day all the monkeys will not reach for a banana thrown into the cage. Later, one of the monkeys is swapped out for a new one and a banana thrown in. The monkey starts to reach for it, but the other monkeys beat them and prevent them from doing so. The process is continued until eventually all of the monkeys are replaced.
At this point, we are left with a cage full of monkeys that will not touch the banana.
... but no one really knows why... They just know that they can't.
So we're left with Henry Ford's admonition. "Whether you think you can or you cannot; You're right."