On Tue, 9 Mar 2010 15:19:58 -0000, "Mungo \"Two Sheds\" Toadfoot"
wrote:

How powerful are they? Will any of them go through, for example, a 10mm
steel bolt in less than an hour? Any specific recommendations other than
"angle grinder"?

Si

The smallest ones rely on high speed with fairly decent torque.

Any of the common ones, dremel,aldi or lidl are fine for diy use, the
problem lies in the area of the tool used more than what you use it
in.

A bolt like you specify would present no problem, I have cut loads of
rusty ones off cars and lent mine out to friends for similar purposes.
A sanding barrel will also make short work on a window frame.

As said the tools used are the problem. All those boxes of grinders
you see seem to have the grindstone fixed to the shaft with the
equivalent of the glue gun stuff and drop off as soon as they get
warm.

If you buy the premium dremel tools they do work. You get what you pay
for.

So for sanding and cutting, particularly in confined spaces they are
brilliant, forget all the grinders unless you pay a lot for the
grinder.