Tightening all three holes reduces any such tendency. Ask any machinist
they will tell you "tighten at all holes".


I've been a Tool and Die maker for over 20 years and I disagree with your
statement. A drill chuck isn't meant to be accurate, nor is it meant to be a
three jaw lathe chuck. I'm not saying you can't do some cheating here and
there, but expect the accuracy of your equipment to take a beating. I do
understand that you can't always have the perfect tool for every job that
needs to be done, but you gotta be careful when you improvise. Remember, a
drill press isn't designed to take side loads, and neither is a drill chuck.
With that being said, I'll admit that before I bought my first CNC lathe, I
used one of my CNC mills as a lathe to make simple plastic parts.

Perhaps the difference is the quality of my equipment. The drill chucks I
use are completely rebuildable, and cost almost as much as some people spend
on their whole drill press. Perhaps that's why I've never had an accuracy
issue when tightening only one hole. Or, maybe it's because if I really need
it to be accurate, I use collets instead.

I think your ideas are very reasonable if the craftsman doesn't get in a
hurry and chooses his cutting tools carefully. Avoid clamping things to the
table, and feeding in with cross slides if you have that capability. As long
as you're using hand held tools, it would be difficult to overload your
bearings, and with your mounting idea, you'll be less likely to have the
part go flying across your shop. Especially if you back up the end of the
part like you suggested.