Pilot hole needed?

[Dave]

I have to a (SDS) drill 16mm hole in some brickwork for a rawlbolt. Is it best to drill a pilot first? I think probably not, as presumably SDS is designed to start with it's own leading edge (?)

[The Natural Philosopher]

Depends on how accurate it needs to be - a hammer type action tends to overbore a bit epecially at first.

Mostly no one cares, as most of the strength is from the deeper part of the hole.

[Stuart Noble]

Can't do any harm to start with a 5mm bit. I usually use a non hammer drill for any kind of precision. My SDS bounces about a bit too much

[Christian McArdle]

I don't bother. I do start with hammer switched off for accuracy, though.

Christian.