To hold the centerline on the workpiece will help the device shown in the figure.
Recommend to read
COMBAT BECOMES PEACEFUL
Dedicated to the memory of General designer Mikhail Kuzmich Yangelya. In issue No. 7 of 2000 published an article "the workhorse of the launch sites" dedicated booster light class —...
THE MYSTERIOUS SCREWDRIVER
This screwdriver can be used to tighten the screw in the most difficult and hard to reach places without fear of dropping it — Spitz sits on the tip of the tool like glue. The secret is...