This is a simple mod of a pencil sharpener to prepare pencils for lead hardness testing
Insert pencil and mark the blade where pencil lead and wood meet
Use a grinder/file/? and remove the cutting edge where the pencil lead is
Insert pencil and sharpen until pencil lead sticks out past the wood the distance you like (I go a little under 1/4 in)
Flatten point of pencil lead with sandpaper