drilling hard brick with weak mortar

[Ouch77]

I have the difficult situation where my house is made from very hard local brick, combined with a pretty soft mortar (apparently made with stone dust). In my renovations I'm finding a good portion of the time when drilling into the brick (SDS with decent bosch bits) the vibrations of the hammer drill loosen the brick within the mortar, thus negating the security of whatever fixing I'm trying to put in, as the brick is no longer one with the wall. I've tried varying the speed of the drill, slower just prolongs the agony and the brick still occasionally feels loose, too fast and I melt the drill bit.

Freqently these are small holes, up to 10-12mm diameter, bigger stuff is core drilled, which takes an age, but usually results in the brick not coming loose unless I run out of patience and chain drill some small diameter holes with a hammer bit.

Does anyone have any suggestions? Anyone else been in this situation (it can't be just me..)

 

[aveatry]

Start off with a 4mm drill pilot hole look at this thread for some good tips. https://www.diynot.com/diy/threads/why-am-i-so-inept-with-wall-plugs. I now use the bosch small drill bit mentioned. Its a 9 cyl or somthing and is very good. Maybe the sds is just to violent, try a good cordless on hammer as I think its a shorter faster action if you know what I mean and start with a small 4mm then build up to the 10mm with ever wider drills and you should not need the hammer action on that is causing the damage.

 

[Notch7]

I use dewalt extreme masonry bits, then do exactly what Aveatry does: drill a 4mm hole, then a 6mm hole etc

 

[Wayners]

If drilling causes problems. Use duck tape to cover all the bricks and repoint with lime mortar or whatever it is. No skill required