What do you cut to prove your knife is sharp? Some people cut rope. Others slice away at paper or pumpkins.
The other day I cut arm hair. My forearms, unlike my head, are heavy hair zones. And the once-dull bread knife I held in my hand sliced right through the forest of follicles with nary a hitch.
Cutting the hair on forearms may be an indicator that you need a few days off, but it also shows that your knife has a keen edge. At least that is what Daniel D. Friel Sr. told me.
Friel told me this as he stood next to me, trimming the hair on his forearms with another of my resurrected kitchen knives. These knives were once so dull they had a hard time slicing bread and were now sharp enough to cut hair.
The knives had been pulled through a sharpener, a variation of a device Friel invented several years ago, after spending hours in his basement trying to sharpen his family's knives. The $80 sharpener, called Chef's Choice Diamond Hone, is widely known among the world of professional knife-wielders. Consumer Reports magazine used Friel's device to sharpen the kitchen knives it rated in its August 1993 issue.
Friel, 72, got a bachelor's degree in chemical engineering from Johns Hopkins University in the early 1940s. After retiring in the early 1980s from the Du Pont Company he took on a household project that had long been bothering him. Namely, getting the kitchen knives sharp.
Grabbing an old set of knives, he went to the basement of his family's home in the Wilmington, Del., area and set to work. Three years and 13 prototypes later, he emerged with a sharpener that became the cornerstone of his new company, EdgeCraft. The company, based in Avondale, Pa., manufactures a line of equipment ranging from knives, to scissors sharpeners, to knives used to cut microscopically thin tissues used in biological research.
On a recent trip to Baltimore, Friel talked about sharpening knives, and showed me how to shave the hair on my forearm.
Friel said a common knife-sharpening problem people have is holding the blades on a consistently correct angle as they pull the blade over a sharpening stone.
When you have an uneven angle of attack, one side of the blade edge ends up looking different from the other edge, he said. Friel showed me a drawing of what the tiny pieces of metal look like on the edge of a dull knife. The dull ones had bad posture. The pieces of metal slouched, at least that is what it looked like to me.
This bad posture leads to dullness. So in his battle against dullness, Friel put magnets on his knife sharpener. When you run a knife through Friel's sharpener, the magnets grab the blade and hold it on the correct angle.
I watched as Friel took one of my deadly dull kitchen knives and pulled it through the four different sharpening stones on his device. Later, feeling brave, I even pulled a knife through the machine myself.
The results were knives with edges so sharp they could shave forearm hair. I liked this procedure because it was the only time I felt blessed to have hairy forearms.
But Friel said cutting hair was also a good test of sharpness. Hair, he said, is lightweight. And when a knife comes up against something light with little resistance, like hair, the edge must do the cutting, he said. There is no pressure or sawing action from the blade. So, he said, to cut hair, the edge must be razor sharp.
Similarly, Friel said, when you cut a piece of paper, the best test of a knife's edge is to cut the paper when it is floating in the air, unsupported, not held tight, he said.
There are other ways to test a knife, he said. Cutting coarse rope tests the knife's durability, or how long the edge can retain its good posture.
And since pumpkins have tough fibers, cutting them, he said, is a common industry test of a knife's slicing ability.
Friel assured me that my kitchen knives were now sharp enough to slice pumpkins.
This was welcome news for me because Halloween is just around the corner. In previous years I carved the family pumpkin with our usual collection of very old, very dull knives. It was a struggle. Especially sawing out the teeth.
But this year with my newly sharpened knives I won't saw the jack-o-lantern, I'll perform pumpkin surgery. Provided I don't slice my finger off in the process.