Making a marking knife from an old planer blade – part 1

A marking knife is one of the most useful tools in my toolbox. I use it to score lines in preparation for sawing or chiseling. I own several knives but the one I use most is the new slim blade Veritas knife. Last week I made my first marking knife from scratch. It all began when I replaced the blades in my portable planer.
Theses blades are made from fine grade carbide and are very tough. Whenever possible, I always try to reuse things and so, when I looked at the old blades, I scratched my head and wondered how I could repurpose them. I had two ideas: one was to make a marking knife and the other one to make a tiny chisel.

Once I identified what I wanted to do, I had to find out one important fact: can these blades be sharpened, and with what kind of sharpening medium?
I first tried the grinding wheel (I have the Norton 3X) which didn't even scratch the blades. Then I tried our DMT diamond stones and was relieved to discover that I could sharpen the blade relatively easily. Here is a picture of a sharpened blade near one that has not been sharpened. I was able to obtain a keen edge with the 1200 grit stone so I didn't attempt to use my polishing water stone as I would normally.  Also, my disappointing experience with the girding wheels taught me a lesson: Carbide yields only to Diamonds. 

Next I continued to make the handles. I chose Rosewood and grooved the two halves of the handle (to nest the blade in) on the table saw. 

I tested the fit, cleaned the grooves with a narrow chisel and prepared the parts for gluing up with Epoxy adhesive.  

Next time I will show how I finished the knife. 

American Woodworker Blog
Yoav Liberman

About Yoav Liberman

Yoav S. Liberman is a woodworker and a teacher. His pieces have been featured in several woodworking books, most recently in Robin Wood’s CORES Recycled. Yoav teaches woodworking at the Rudolf Steiner School in Manhattan, and also frequently guest teaches in craft schools across the country.  Between 2003 and 2011 Yoav  headed the woodworking program at Harvard University's Eliot House. Yoav’s articles have appeared in American Woodworker and Woodwork Magazine. He frequently contributes woodworking web content to a number of digital publications   Yoav has a degree in architecture and later held two competitive residency programs: at The Worcester Center for Crafts in Massachusetts, and the Windgate Foundation Fellowship at Purchase College, New York. He lives in Chestnut Ridge NY.