Every year or two someone asks which vice the should they buy, which generates the usual rash of opinion and advice. It's been a couple of years and I think I want a vice, so this post.
Recently (other threads) I acquired a new mill. It biggish – 820×210 table (an Amadeal VM32L – much like a WM18 in size).
So my first question is what size vice makes sense? Currently I have a 2 inch machine vice and a 3 inch RDGTools vice which looked big on my CMD10 and a bit silly on the new mill.
I'm thinking that 5 or 6 inches (125/150mm) is about right. 8 inches seems excessive (oh ah, vicar…).
Now, In previews posts people either had a vice which was very accurate or used a lead hammer. Sometimes both. What weight should the hammer be for a machine of this size? Can you use other mallets? Wood/Rubber?
Then I wonder about new (Chinese) vs second hand. My first problem is that the second hand vices cost almost as much as a mill – and some of them look pretty ragged. Does a 10 (20/30) year old vice retain it's accuracy?
The previous posts mainly talked about the Kurt vice (which costs more than many mills) and Kurt clones. Apparently (in 2017) ARC were about to take on a Kurt clone which I think is the 'versatile milling vice'.
And then there are the hundreds of 'acculock' vices on eBay – which I guess are Kurt clones of various qualities?
And as far as I can tell there is no machine vice made which isn't 'precision' – regardless of quality!
My budget for this is £100 (or less) which puts most of the options out of scope. Is it worth applying several months of budget to a vice? What will I really see as a difference in my machining? Should I just buy a cheap (ish) vice and lead hammer.
In anticipation of many conflicting responses … 
Iain