Installing wheel studs in Yukon axles

I'm running into a problem and hope someone can shed a bit of light for me. I have a set of new BBP Yukon axles I am putting in my 8-3/4 and I am trying to install new 1/2" wheel studs. The problem I am running into is they don't seem to pull in when I try and tighten them down with a lugnut.

Just curious if the metal is harder on the Yukon axles which makes it harder to pull the studs through? I'm interested on any other techniques that some of you guys might have done that may help me out.