On 17/02/2021 15:35, Jimmy Stewart ... wrote:
Just got my first keyless chuck drill and I am having
problems......bought a new bosch 550 wired drill to replace my old black
and decker and Stanley drills and a 20mm masonry drill to open up the
holes in a teracotta airbrick.....anyway got the bit tightened and
started drilling on the hammer settings and after a few seconds the
drill fell out and rolled down the roof to the ground......this can't be
normal... am I doing something wrong?....instructions just say tighten
until clicks are heard......doesn't matter how tight I make it the drill
still falls out....any ideas ? ...

Never come across with one that makes clicks. I am not particularly keen
on them, but if you really can't get it to grip however tight you do it
then it sounds like it is faulty. You are taking care to centre the
drill as you tighten it, I assume? If you start with it wide it is
sometimes possible to get it to grip on two jaws only, in which case it
will come out when you use it.

On my Makita cordless you need to set the gearbox speed to slow to get
it properly tight; on high speed you can make the motor turn backwards.

Or is this one where there is a second collar on the chuck, so that you
grip both when tightening.