Always hate to waste a decent diagram, so here's what I posted on a FB page when the subject of drill press fretting came up earlier today.
While great for what they do best, drill presses aren't meant for any extremes of downward pressure on the working table. Normally this isn't an issue for fret-pressing, but sometimes......whoops.
So, about 5yrs ago, my nice old Craftsman floor-mount drill press suffered a cracked table yoke while refretting a stubborn Ibanez neck.
Someone (forgot who, maybe somebody here) came-up with a great idea to keep it from happening again and I use it religiously. In fact, a couple of different lengths of 2X4's are good to accommodate different table heights. Good, cheap insurance :)
Had the exact same thing happen to my Delta and used the same solution after fixing it. Good prevention.