It sounds like the coil might be sitting too high on the deck, and when you try to screw the whole base in, the chimney is pushing up on the coil. This happened to me once when I made one of my coils really big because I ran out of my normal 26g wire. So I used 24g wire instead instead. I usually do 5 wraps with the 26g around the little screwdriver that came with my subtank mini and this gives me 0.5-0.6 ohms which I really like. The size and width of the coil is awesome for the Subtank mini rba deck. But since the 24g wire is lower resistance, I had to make the coil bigger diameter wise to get 0.5 ohm. I could have made it wider but I find 5-6 wraps the most I like to go with the rba deck. Anyways the coil was hitting the chimney and I couldn't screw the base in. Solved the problem by seating the coil lower on the deck.
P.s. I'm still quite new to building my own coils so I'm sorry if my terminology is off, or if it's difficult to understand what I'm trying to say. I don't use a jig or drill bits so I cannot give accurate measurements of my coil diameters etc.