Originally Posted by
Doug Fattic
I took a picture of my Niles, MI based Anvil lower HT cone. This one did not have very tight tolerances between the 2 pieces. The cone came right out of the socket. The bolt is a 1/4" X 20. Just to repeat, dsaul's suggestion to unloosen the screw a few turns and hitting the screw head with a hammer would be my choice. If for some reason it didn't loosen, then I'd go to plan B. The likely culprit is flux that has seeped into the cracks acting like glue. You might try pouring or soaking the part in very hot or even boiling water. That might dissolve the offending flux and at the same time provide heat that might break the bond between the aluminum and steel pieces.
Interesting my jig has a lip for the largest part of the cone to "sit" into, he must have changed his design at some point. The previous owner was tig'ing in this jig but who knows before that, could have some flux in there.