Over the years I have tried about every means of marking wood.
I like mechanical pencils because they do not need sharpening and fit with clips in my pocket.
But standard lead sizes break to easy when scribing wood.
For the last year I have been using pencils with 1.3mm lead successfully.
Until recently I could only find versions that were made for kids and the lead and erasers were not replaceable.
I found this set that I really like. They are real mechanical pencils but with 1.3mm lead and standard erasers. They are surprisingly good quality
Here is what comes in the kit:
Here is a bonus: if you want to mark on wood without any permanence try these. However these leads are very fragile. That said not having to try and sand out the marks is worth the frustration of breaking leads.