Spirit level vial accuracy terms...

[10KPete]

I was looking at level vials and find I'm not really clear on what the accuracy terms mean. The accuracy seems to be stated as "6'/2mm" or similar on these vials but what does that really mean??

Thanks,
Pete

[mklotz]

If that's all they say, they need to more clearly explain what it means.

My guess, and it's only a guess, is that it means that a 6 arcminute tilt of the vial will cause the bubble to move 2 mm.

6 arcminute = 6/60 = 0.1 degree

[10KPete]

Most interesting, Marv !!  It read as six feet to me.  I think I'll send the guy an email and ask that question. Nothing to hide.....

Pete

[crueby]

There is a good writeup of how the sensitivity is specified here:

https://www.leveldevelopments.com/sensitivity-explained/

[10KPete]

Thanks Chris!!  That is exactly what I couldn't find....

Pete

[mklotz]

Most interesting, Marv !!  It read as six feet to me.  I think I'll send the guy an email and ask that question. Nothing to hide.....

When writing angles in deg, minute, second notation it's common to use the single quote (') for minutes and the double quote (") for seconds, thus...

12º 34' 56" = 12 degrees, 34 minutes, and 56 seconds

[Mosey]

Starrett has a  definition of the markings and accuracy of the various precision of their machinists levels somewhere in their older tool catalogs, but I apologize for not knowing where it is found. I'll fish it out in a day or so. They state what the markings mean in terms of degrees per foot of length of the tool blade.
Mosey