On Mon, 07 Sep 2009 23:55:28 +0100, John Rumm
wrote:

If you get a bit hot enough the weld will fail that holds the carbide
edge. Did the bit change colour or start to get a blue sheen? If it did
that would indicate overheating.

No, it didn't overheat nor turn blue.

The Bosch ones I use regularly are their "multimaterial" bits which I
find to be excellent - they in theory drill everything, but are
excellent on masonry.

I have used those in a non-sds drill but I thought they only went up
to about 13 or 14mm and in short lengths. I didn't know they did wide
and long sizes too. This was just a "plain" Bosch sds bit.