How do you measure the root of a screw?

[Orange Tortex]

I need to find the root of some screws so I know what size drill bit to use when drilling pilot holes. Is there a tool that can measure the tiny spaces between the threads? Or is there some kind of formula for finding the root by measuring the threaded sides?

 

[Rick]

The Aaron had a video on this.  Check warmoth's youtube channel.

 

[aarontunes]

I've talked about it in a bunch of vids. This one, e.g.


[youtube]https://youtu.be/68UR6bXBDTY[/youtube]

 

[Verne Bunsen]

I just hold the drill bit up in front of the screw and find the one that covers the shaft and leaves the threads exposed.  :dontknow: And I always use a conical grinding stone to "countersink" the finish around the hole, which prevents cracking when the screw is installed.

 

[TBurst Std]

I just hold the drill bit up in front of the screw and find the one that covers the shaft and leaves the threads exposed.  :dontknow: And I always use a conical grinding stone to "countersink" the finish around the hole, which prevents cracking when the screw is installed.

While I have a tool to measure it, this is still the way I do it. Eyes are better than any camera, the brain better than any computer.