In message , freddyuk
writes

I will probably get flamed here but here goes - i bought one of those
Chinese SDS drills with rotostop and a kit of bits from France for euro
30. I was so impressed (for domestic use only) i bought another one on
my next wine trip. A few months later they appeared in Srewfix etc.
selling for about £40.00 without the bit kit.
One of mine has lost its "hammer" action and i was wondering if there
was a way to repair it easily. It has not been used very much so worth
repairing if i can. The other one has been used a lot for digging up
concrete etc and has proved to be a real bargain for the price.

Anyone any ideas or experience?

I have the reverse of your problem.
My Bosch drill has developed a slight hammer action on *drill only*.
Years of abuse with oversize drill bits may have moved the hammer cam
along the shaft such that it is in permanent contact. Yours seems to
have gone the other way:-)

I don't know how these parts are assembled but the hammer collar may
just be heat shrunk to the shaft. Minor tolerance variations/abuse
perhaps have allowed it to slide out of position?

The annoying thing about even slight hammer action is that it blunts
conventional metal cutting bits:-(

regards
--
Tim Lamb