I saw this idea on the on Pinterest a year or two ago and have been itching to actually do it myself. I knew I wanted to keep the wood a natural look, but I debated between painting the numbers on or using a wood burner to burn the numbers in. I tried my handheld torch and that didn’t work, I looked up chemical reactions to burn in a wood design and decided not to blow up my house. After all this it hit me that they make hand held wood burners.
Check out how it turned out. You can see closeups and some of the process.
This is the Spool before I did anything to it.
Here is a closeup of a few of the numbers: