"I bought this to chop out a row of bricks so i could fit a cavity tray, The instructions said to drill a 10mm hole and insert the rake into the hole, I found it a bit slow so i ended up drilling a series of holes along the mortor and then found the tool cleared out the remaining mortor. It also doesn't quite reach to the back of the brick so had to chop out the rest of the mortor by hand. On the plus side it causes less dust than an angle grinder which saves time on clearing up at the end of the job."
"Slow going, but then again my mortar is VERY hard, real man's mortar! Probably works best on soft crumbly material, or possibly old lime mortar. At least it didn't break like some reviewer's examples, but in places the carbide material has worn away. Only advice I can give is to read manufacturer's instructions re: only use for 5 mins then stop."