Jim,
Let me admit that the first time I saw a wood lathe I was devastated at the cack handed way it was designed and literally thrown together without any real attempt at an engineering masterpiece they in my mind should be firstly for the price secondly for accuracy.
The common excuse used to be its only for wood you know. What do you expect for fourpence Crayfish? The I saw my first mandrel a horror production with a long 1/4 inch roughly stem extending from the one piece soft steel no 2 morse taper base, then the least exciting thing was the tiny recess for the tip of a live centre invariably never matching ( 60 degrees and all that never talked about) thats when I made my first wood lathe then eliminating the point entry to the mandrel, having observed my mates all forcing their other turning hand to the spinning pair of blanks I decided and ever since practiced only turning half a pen at a time shortening the mandrel, cutting off the threaded section and recessing the mandrel around 3/8 th of an inch into a brass sleeve fitted into the live centre thus creating the very first form of mandrel saving. Did I cop a serve from non handy turners.
Now what I would like to see is a collett holder fitted to an accurate no 2 morse taper shaft (mission accomplished) what I did for years was use a thread converted spare chuck from my Hercus Metal Lathe (smallish one) with a fitted shield to protect my nuckles from the three jaws. Spent an innordinate time matching the two points from the head and tail stock (try that sometime) and find more short comings of wood lathes 9 No adjustment abilities etc).
Perhaps I should stop here because I have applied these principles to every part of pen turning to make repeatability, comfortable for me including a sit down bench adjacent pen press,variable speed tiny buffer etc plus plus.
Guess what one year to go for 80 yrs tells me if their is a better way and I feel I can improve my lot I will, so disregard all of what I say for yourself fight your own battle of Warterloo but do not be downhearted when you try to share pen turners unite to pick holes in every little thing rather than put them to the test.
With regard to Mandrel Savers I have purchased many different ones, used them all to find out for myself how true the description and technical production actually is imagine for example how I feel when prepurchase the gab says precission and I find a 4 dollar tiny bearing designed for round thrust no concern for push thrust and extravagent claims of accuracy etc the dependant bearing.
Anyway yes I am in favour of Mandrel Saving in the best way possible for ease of use in my dedicated Pen Turning Lathe, the heavy steel bench I welded fitted an 1 1/4 inch laminated top bolted on the lathe driven from the head stock to a three phase motor mounted on the left hand side on top of the bench for free leg space and ease of fitting a separate infinite speed controller, really enjoy making and using the forty odd mods since to fine tune allowing me to design and build happily at my bench.
To the Anti or luke warm mandrel lovers I salute you hastening to say threr is always a better way to suit everyone.
To reply in all things with great humour and comaraderie is noble easy and less time consuming so to this end finding contentment with acheiving will satisfy me more, have fun I intend to.
Kind regards Peter.