Janka Hardness by Jana L | Mar 2, 2022 | Glossary of Terms, Glossary of Terms -J, Uncategorized | 0 comments Refers to the strength of the hardwood material based on a scale which determines the amount of force it takes to drive a .444 inch steel ball into a plank of wood .222 inches in diameter. Submit a Comment Cancel replyYour email address will not be published. Required fields are marked *Comment * Name * Email * Website Save my name, email, and website in this browser for the next time I comment.