I think in the concrete wall drilling installation expansion screws do not know is good or impact drill hammer.
With a hammer, I did Aluminum Alloy steel doors and windows, hitting the expansion screw hole is used in electric hammer.Difference, go to Baidu encyclopedia see you understand.
Two samples can be, if it is a brick wall with the impact of drilling well, because the brick walls are not very hard, you may use the electric will hole bigger, the expansion screw is not tight, if it is a concrete wall with hammer is better, because the concrete wall is too hard, with the impact of drilling drilling may not dynamic,
Percussion drill. The only choice for personal use.
