Marker (Sharpie) Pen Test

rbscebu

Member
Joined
Sep 10, 2020
Location
Atherton Tablelands, Queensland, Australia
Whenever I get a new or new-to-me straight razor (SR), the first thing I do before the blade touches a hone is a marker pen examination.

What you need is:
  • A black permanent marker pen.
  • A 10x or 20x loupe.
  • A reasonably fine (about 10k) perfectly flat whetstone or equivalent lapping film.
  • A good light source.
  • Your "new" SR.
What to do:
  • With the marker pen, put the black ink on the blade's bevel both sides and the spine-wear area both sides, and allow to dry.
  • Using very light pressure (weight of the blade only) hone the blade 2 to 4 laps on the whetstone/lapping film. This can be done dry, edge leading or trailing.
  • Using the loupe and light, examine where the ink has been removed from the bevel and spine-wear area.
The observed results will show you where the blade is making contact with the whetstone/lapping film. With this information, you can determine the condition of the blade's previous honing and what type of work you will need to get it to your desired condition.

The marker ink can be easily removed from the blade with cotton wool and acetone.
 
You can also lie the blade flat on it side on the stone and see if it 'wobbles' when you apply light pressure to either end of the spine.
Flip it over & do the other side.
Hopefully there is no movement otherwise you might have a banana for a blade.
 
You can also lie the blade flat on it side on the stone and see if it 'wobbles' when you apply light pressure to either end of the spine.
Flip it over & do the other side.
Hopefully there is no movement otherwise you might have a banana for a blade.
Yes, but all may not be lost. It is not uncommon for a SR direct from the factory to have a slight wobble. I have experienced t his with cheaper Asian blades and much more expensive Eurpean blades. If not too great, this can be honed out of the blade.

The sharpie pen test tells you a lot more about the blade and how it was previously honed.
 
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