Drilling a concrete post

[meccarroll]

Has anyone drilled a concrete post? I have one I'm thinking about drilling to attach a wooden post to but am not quite sure if the concrete post might shatter or split. It's something I've not had to do before so if you have drilled one with success or failure please let me know.

Mark

 

[Mike G]

It will have reinforcing in it. Use a masonry drill, and drill slightly off-centre to avoid hitting the reinforcing. Don't bash the plug in too hard with a hammer as these posts are brittle and smash easily.

 

[AndyP]

Perhaps try without the hammer mode on the drill to start with.
I have a concrete post and rail fence and after one of the rails was reversed into and broken into 3 pieces (by persons unknown) I had to screw some angle iron into the rail and "glue" it back together as it is impossible to replace the rails without removing the posts. I choose to use a chemical fixing for the screws.

 

[Doug]

Drilled quite a lot of concrete posts, they usually have 4 thin reinforcing bars held by a plastic clip running through them so drilling on centre is usually the best bet if you want to avoid them, I use an SDS with a 4mm masonry bit to drill the initial hole, you get some break out but if you drill in the right direction that will be covered by the timber post

 

[meccarroll]

Many thank's Doug and Andy for the replies.

Think I'll go with a small bit as suggested to start off with. I don't think I'll manage to drill concrete with a rotary bit (without hammer/SDS) but I'll give it a try first, if it works it would certainly help. I may get away fixing the post using the two existing holes already in the concrete post and just bolting the wood post to the concrete one the only problem is the last hole is about a third of the way down the concrete post so I may not obtain a satisfactory fixing without a further hole drilled out further up the concrete post. At least I now have a couple of suggestions to try Cheers.

Mark

 

[meccarroll]

Just to let you know drilling the post went fine. I used a small drill bit first as Doug suggested then widened the hole with a larger drill bit. I drilled central to the post to avoid the steel reinforcement bars. I just had a little breakout on the back of the post where I drilled through (all covered by a fence panel. Thank's for the help and suggestions.

Mark

 

[Doug]

Glad to hear you got it sorted, I find the main problem is if you hit a piece of gravel within the concrete with out SDS getting through those is almost impossible.