Step Right Up

and watch me burn a chisel

As part of my series on drawknife sharpening, I want to show how to grind a drawknife. But first, I want to lower the stakes and practice with a cheap ($2) chisel from Habitat for Humanity Restore. I bought three because I was feeling greedy.

I made a video about grinding one of these with the express purpose of showing techniques for grinding without heating up and then I demonstrate how to behave to ensure you do burn and ruin the edge.

For those who are unfamiliar, tools such as chisels are high carbon steel. To make a durable edge, high carbon steel is heated to a very high temperature and then quickly cooled to lock it in a very hard state. Then, it’s heated again to soften (temper) the steel to the desired hardness. If you heat it up too much while grinding, it will continue the softening process and “lose it’s temper”. Yes, that’s where that phrase comes from, easy to remember. Losing your temper means you are getting too “hot”.

This video isn’t about getting a perfect grind or straight edge, it’s about becoming familiar with the tools. Like driving in an empty parking lot before hitting the highway, I truly believe everyone should lower the stakes by buying some near dead tools and burning them up. You will learn tons.

I especially like this lesson to be well learned before jumping to grinding drawknives. They aren’t very different, but they are a bit unforgiving if you seize up like a cadaver once the sparks start flying. In the video, I do quench the tool in water during the process because I’m removing a lot of material on a very fine stone. I almost never find this necessary. During normal grinding operations, I am usually removing so little material the heat build up it isn’t a concern. Try not to rely too heavily on quenching, it’s a sign you might be applying too much pressure or removing material too fast. In the video, I show applying a lot of pressure to create the heat to burn the edge, but if you are letting the tool heat up too much during regular grinding, you might be close to burning without so much pressure, especially as the edge gets thin. Another reason to go slow and run cool.

Next I’ll show drawknife grinding. I learned to do it freehand from Dave Sawyer, maybe I’ll show that for fun. Luckily there’s an easier ways to get a good grind. I learned to do the grind freehand when drawknives were still $20, not quite $2, but the stress was definitely lower.