Hi Arvind. What Charles said. A lot of older Craftsman routers never had the option of 1/2" collets.
Might think about upgrading. Newer Craftsman routers are more powerful, and most will accept 1/2" shank bits. And, with Black Friday sales coming up, should be able to get an even better deal on one. Look for a dual base set, best of both worlds that way... fixed and plunge.
Sometimes I wonder whether the world is being run by smart people who are putting us on
or by imbeciles who really mean it.