John Rumm wrote:
On 15/05/2010 15:12, spamlet wrote:

What does 'SDS' mean anyway? 'Define: SDS' in google comes up with
nothing
about drills.

Often incorrectly claimed to be special drill system or similar[1], it
was originally the German phrase: "Steck - Dreh - Sitz" translating to
Insert, Twist, Lock or similar.

[1] You can get (Bosch) jigsaws with SDS clamping mechanisms as well.

What is it that makes 'SDS' able to do a job that a 'hammer' drill won't?

By hitting the bit *much* harder while turning it.



...using a mechanism that has NOTHING to do with SDS bit locking
whatsoever...

So what you have is that SDS is a bit lock mechanism,m. But what people
MEAN by 'SDS drill' is one that has an impact mechanism different that
which is found in a normal 'non SDS' hammer drill that simply use
something like a cam system to judder the bit forwards and backwards.
The 'SDS 'has an impact system that literally hits the back of the shaft..

The fact that these two completely different and unrelated mechanisms
both appeared at the same time on the later generation of drills, is
what has completely confused the whole arena.