Site Measuring Joists - Web Thickness

[EngDM]

Hey all,

Just wondering if anyone has a solution to finding a web thickness of a hollow round bar member. I want to perhaps bring a drill and put a small hole, but what tool could measure thicknesses off that? My callipers would require quite the substatial hole.

There is an old joist type up in Canada where the OD is the same but the thicknesses vary throughout. As of late we have just been using the minimum size and reinforcing heavy, but I'd like to find a more economical solution.

 

[dik]

uggering on the interior surface of the hole can make this inaccurate

Can you not remove this with a 'rattail' file to remove the burr?