I buy impact rated bits. I got my set from Granger, they were on special for around $30. I don't think they make this exact set anymore, I think they updated the tools.
http://www.all-spec.com/products/073983....ApY-8P8HAQ
http://www.all-spec.com/products/073983....ApY-8P8HAQ
tackit, proud to be a member of MetalworkingFun Forum since May 2014.