Do you know how to make better joint stems digitaly?

I have another question… are there that many digital sculptures here? I’ve been fiddling with a few new programs, & I had a question about making better stems for screws to go into. With a few pieces that I have made, I’ve noticed that I have had a problem making a clean joint. Normally what happens is that I have problems being able to get the screw to go in smoothly. I’ve even tried using soap/wax to grease the treads so that it would go in smoother. The only thing that I can think of to make things easier is to scan the screw that I plan on using, make a negative image of it, & build a stem around that. Any tips that anyone could throw out there? The pieces that I have been making look fine, it’s the screws that I tend to have a problem with.