How are minutes used is sensitivity? What does 35 minutes per 2mm mean in leveling and engineering?

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How are minutes used is sensitivity? What does 35 minutes per 2mm mean in leveling and engineering?

In: Engineering

Minutes are a part of circular measurement. 60 minutes equal one degree and 60 seconds equal one minute. So 35 minutes per 2mm means 2mm corresponds to 35/60 (or 0.58 degrees)

Degrees of a circle, 360 of them right?

If you want to describe an angle that is less than a degree, a degree is split down into 60 minutes. If you wanted to describe an angle that is less than 1/60th of a degree, or less than one minute of angle, you’d use seconds, which are 1/60th of an angular minute.

If it’s on a production drawing, it’s because someone hates you, because that’s a virtually impossible standard to keep.

There are 360 degrees in a circle. There are 60 minutes in a degree.

So you’re going for 35/60=0.58 Degrees off plane per 2mm.

Listing it “Per 2mm” implies that you’re going to keep adding 0.58 degrees every 2mm, creating a curve or series of staggered lines. I’d be guessing what the intention is, but it’s probably obvious if we had the drawing to look at.

Listing “Minutes per 2mm” is weird though. Typically it’s either “Degrees/Minutes” or “Xmm per 2mm”, giving you a triangle to solve for degrees if need be.

As a side note, surveyors use degrees-minutes-seconds to get high precision with only six numbers. It would take a lot of decimal places to get the same precision in decimal degrees.