Concrete fence posts

[ray316]

I have put concrete fence posts in and would like some help and advice on drilling for gate and driveway fittings.
I have drilled the driveway concrete posts and using timber attached to the posts but when l drill through the concrete posts it crumbles a fair amount of concrete off the post on entry and exit of drilling .
I’m using a sds 10mm on hammer drill , what am l doing wrong as this has happened on both driveway posts.
I have the pathway gates to fit now and would like to try and get these done with clean drilling holes .

 

[stevie888]

Use a small bit and go through being very gentle over the last bit (try without hammer) then open up coming in from both sides

 

[Hobobanobo]

I'm interested in how this goes, as I will be doing the same thing this spring.
I have 2 Corner posts 7 foot tall I want to bolt a wooden frame too for a gate.
There is not a change in hell I'm getting those posts out if it breaks. So any advice is appreciated.
Is SDS required you think, I have a decent sized drill in my Dewalt combo set I recently purchased. Was going to use that.
Fix with 10mm concrete bolts after drilling 8mm holes? 3 per post perhaps.
Terrified it will break.
At the front I need the same but no fence yet. I may just throw wooden posts in to save the hassle.