Coefficient of Friction Testing

[JamesCH95]

Originally Posted by Ether

They do not require calibration by the user because they are calibrated at the factory. That is a source of error, analogous to using a bubble level to locate a level surface for test set-up.

In most modern buildings, it is easy to find a flat level location using a bubble level. Once that location is selected for the test setup, multiple "tilt" tests can be conducted without the need to measure the gravity reference each time.

Whether or not the factory calibration of a device with a built-in level is inferior or superior to the use of a mechanical bubble level is an open question at the moment.

The digital readout of an angle sensor is certainly more convenient¹, but that's not the point of contention here.


¹It's also more expensive if you don't already happen to have one on hand

The electronic angle finder/level that I've used extensively, and that I really like, was calibrated from the factory to +/- 0.2deg of level and +/- 0.1deg angle change from level. McMaster PN 21465A81. Just turn it on and directly measure...

Your average carpenter level is only good to about +/- 1.5deg of level. More precise machinist bubble levels are available of course

You're right, a digital angle finder/level might be considered expensive, but it's the sort of tool that will last for many years of reliable service. It is substantially easier to use and more accurate than a non-digital angle finder. It is especially useful when making complex mill setups or doing complex tube notching and cutting.