Originally Posted by
verktyg
A small internal sleeve will help keep the parts aligned but is unnecessary for strength. Most of the forces are applied on a plane parallel to the steerer.
The welding is usually done while the parts are held in a lathe or a fixture. Butt welding tubing is a standard procedure done throughout manufacturing - from aerospace to automotive to the medical industry.
It's no problem for someone who knows what their doing.
Finding that person is the rub now, isn't it? Most framebuilders don't have that type of background.
Another issue with an internal sleeve, on shorter frames you might be left with not much stem insertion, as it would butt up against the sleeve before you got it down where you wanted it to be.