One thing I forgot sorry about that.
u must check if the ram hammer is wet from oil if not may be that is the reason.
last year I was demonstraiting in STIA with two anyang hammers and I know them
very good.
philip of chaina if u know nothing about air hammers do not advice what to do with them.
and u do not have to humiliate some one for his language, my English is also not good !!!