Has anyone got an explaination on the headers in a hole file?

Hi,

This is a general inquiry on what some of the headers mean in a hole file.

I am unable to find any documentation on these headers. I can only find out about call out formats.

The headers I am referring to are:

FASTENER_ID  BASIC_DIAM  THREAD  TAP_DR  TAP_DEC  PERCENT_THREAD  CLEAR_DR_CLOSE  CLOSE_DEC  CLEAR_DR_FREE  FREE_DEC  CLEAR_DR_MED  MED_DEC  CBOREDIAM   CBOREDEPTH   CSINKDIAM   CSINKANGLE   BOTCSINKDIAM   BOTCSINKANGLE

I know most are self explanatory, however there are some that I am not 100% sure on.

What is the difference between DR and DEC values?

What is THREAD_PERCENT?

I am creating additional hole files and would like to fully understand them first.

Many thanks,

Miles