Sharpening has always been a controversial subject with woodturners!
My experience is that IF you only wish to sharpen for turning, a bench grinder is more than enough. BUT it must have a decent wheel. I tend to use white/pink stones, a 100 and a 60 grit, but as the 100 wears down I have been looking for another and as yet I have not found any, they all seem to stop at 60 grit.
The benefits of a slow/half speed bench grinder are such that as a learner it gives you more time on the stone before over heating, but I think this small benefit is outweighed by the cost of such machines. Especially as all it takes is a little practice and you won't burn the tool anyway.
Slow wet grinders such as the Tormek are great tools but IMO not for woodturning, I base this on the fact that as much as it is nice to have the sharpest edge possible, it just doesn't last long when you have the surface of a piece of timber passing it at yards per second in some cases. The Tormek will give a sharper edge than a grinder, and if you posses one, great I would use it, but they are very expensive to buy just for turning.
Another of the great failings of beginner woodturners is that they don't sharpen their tools often enough. I watch folks at a club I go to and they will turn for a couple of hours and never approach the grinder. When working at home I know within a few minutes how often I will need to redress the tool while working on a certain piece of wood. You should never sharpen when the tool is blunt, you always sharpen the tool before it gets blunt. Even if it means going to the grinder every 10 minutes. Then ALWAYS sharpen before doing the last cut, that way you are getting the best surface possible from the tool.
I used to sharpen all my tools free hand, on a flat platform (aka K Rowley) but after watching Jimmy Clewes, Mick Hanbury and the like I now sharpen my gouges using a jig. I still sharpen all my other tools on the flat platform, but my 3/8" and upwards bowl gouges, and my spindle gouges are all done on a jig.
SO IMO if you are a turner and cost concious a bench grinder is fine, if you have the money buy the best but I don't think your turning will benefit. As with all things in life nothing is that easy and all hobbies need a little patience and perseverance when learning a skill. I'm sorry to say it is not something you can buy.
On this note I will finish, but if anyone is really struggling and wants a bit of help with their sharpening, or anything else. (turning only :twisted: ) Get in touch and we could maybe arrange to spend an afternoon going over bits were you think you are struggling. As with all turners, my way is the best way O
so I can only show you how I do it.