John Rumm wrote:
Tim Lamb wrote:
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 OPs drill sounded like an SDS - hence no cam collar etc.

It is - he said "i bought one of those Chinese SDS drills with
rotostop and a kit of bits"