Callout for threaded hole to be tapped straight

[stilllearning]

Hello,

I am in the process of finishing up a print that needs a callout to make sure the hols are threaded straight. The issue we are having is that the threads are not being tapped straight down and then the BSPP o-ring fitting will not sit flush on the face causing leaks.

Do you guys know of a way to notate that the threads need to be tapped straight?

Any help would be appreciated.

[Kelly_Bramble]

GD&T Perpendicularity tolerance relative to tap start surface...