*PLUMBERSSTOCK EXPERT* responded:
Thanks for posting a question regarding our Milwaukee 14-46-1060 Lg Quik-Loc Blade Clamp Kit. No, it won't work with a 6521-21 saw. What you're looking for is the Milwaukee 14-46-1011. If you are all set to purchase the kit, just click on the link to transfer to the product's page and click on Add to Cart. Enter your zip code to get a shipping cost estimate and proceed to checkout to begin the ordering process. Thanks for choosing PlumbersStock.com as your online shopping buddy. Have a great day!