The upper straightedge has a rounded lip on the right and left sides.
The ruler marks start inside the rounded end, about 1/8" in.
The markings on the bottom ruler start right on the flat side.
I use the bottom ruler more often.
Both centering rings are glued 1/2" from the ends of the tube.
Using the squared ruler against the ring I can easily check the 1/2" spacing from the ends of the motor mount tube.
If the ring is flat against the end of the ruler I know it is perpendicular to the tube.
Rotate the tube and check again from a few different places.
Never really understood why I'd want a steel ruler that does not start at the ends? :) That said, I have one. ???
ReplyDeleteYeah, knowing how I use a ruler now I never would have bought one with rounded ends.
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