School me on my hammer drill

[SteveCh]

Just bought a Bosch rotary hammer drill and started right out using a chisel bit in hammer mode to break out a shoulder of stone in one corner of my garden.

This is the first hammer drill I've owned, and this is the first time I've used one. The reason for the post is that I find that the chisel hammers the rock ok, but only when I find this "sweet spot" on how much pressure I'm putting on the drill. I have to move the drill up and down to reach a spot where the "hammering" action is obvious. A tiny bit more pressure, I feel the drill vibrating but the chisel is just vibrating, too, not moving up and down enough to really see. When I hit that sweet spot, the chisel does a number on that rock. If I don't, it barely does much though it still works some.

Is this normal? Is is simply a matter of getting accustomed to using it?

 

[gsmornot]

Sounds normal and sounds like it might take a while to get used to. In this case it sounds like the stone is very hard. Lifting up to get more "action" from the tool is more like using a regular hammer to break up the rock rather than the chisel cutting through the rock. Normally you would not see an obvious large sweep of the tool other wise the thing will beat you to death. Its made more to vibrate like you describe and work its way though the material. Try it on concrete and you might see more results. Also, take a look at some videos of people using the tool and compare to what you experience first hand.

 

[SteveCh]

Thanks, that is about what I was guessing. Yes, this is hard stone. I have some holes to drill in both concrete and concrete block and will see how it works for that. Yes, it did beat my hands up pretty well, my fingers were tingling [not a good sign] after two hours of using it. When it vibrated on the rock, it made very tiny progress; when it "hammered" the rock, it made ten times better progress.

It is a beautiful tool, and I finalized my choice on which brand to buy after reading the advice here on the forum, advice given to other posters. I continue to learn a lot here. [And spend too much money on tools, I am awaiting an online purchase of an IR compressor, small one, from HD to arrive at my nearest store.]

 

[Strouty]

I would say when you saw it vibrating, you were also wearing it out quicker. Usually the bit should not rattle, that will wear out the chisel and the drill too. The stone may be more than that unit is capable of handling.