No idea about the Dewalt mixer, but here is what K-drill has to say about the Milwaukee mixer. I know some say it works fine, but I would much rather listen to the mfg…
Straight from K-drills website:
“Milwaukee Mud Mixer was tried by several members of our field test staff with similar results by all. Final Results: The heavier Milwaukee Mud Mixer did not have a high enough current load or temp setting to work with the 8 inch K-Drill and would continuously shut down after 2-3 holes. The standard 2703-20 drill far out-performed the Mud Mixer in all of our testing. Until Milwaukee makes some changes to the control circuit in the the Mud Mixer I would be certain it could be returned for a standard 2703-20 or 2803-20 hand drill.”