To hold the centerline on the workpiece will help the device shown in the figure.
Recommend to read
The builder’s “barrel factory”
Owners of private houses or dachas often face the need to prepare concrete solutions. Mixing water, gravel, and cement in a certain proportion is not difficult, but very labor-intensive,...
DELTA-WING ON THE ROCKET PLANE
If you flip the binder "M-K" for a few years, then they will have a lot of materials about models of aircraft raketoplana scheme. But... time goes on and the situation changes. Three or...