Glass and Steel

One outcome of a recent trip to Florida to visit my parents was my father giving me his father’s pocket knife. The knife has come full circuit. My grandfather passed away by his own hand when I was in eighth grade. He was very sick, suffering from emphysema and was chained to a large green tank of compressed oxygen. I always felt I understood his actions as tragic as they were.



I didn’t know my grandfather very well. Relations between these two grandparents and my family were strained and I never knew what was the cause. I still don’t. It’s in the past, buried and dead.


I do remember he used to give me old foreign coins. He delivered soda to bars on Chicago’s south side and he used to find foreign coins that people tried to slip into the soda (?) machines. I’m still a little surprised about the prevalence of soda vending machines in the 40’s and 50’s. What do I know? I remember he was a junker, a collector of copper wire, lead and newspaper for scrap sale. Like many Americans he was green before the concept of recycling. At the time it was called making ends meet. He liked to make elaborate bird cages of wire that he slipped through holes he carefully drilled in little wooden bars. The cages were all painted silver and always reminded me of castles. I’m sure the birds weren’t impressed by their cages, but I was.


My father gave me the knife after the funeral. It was a three-bladed folder, with one broken blade, two excessively sharpened blades in a beat up handle. It was a crap knife then, but it meant something to my father so it meant something to me.

Where's the rest of the blade?

 When I moved out to my first job, I gave the knife back to him. I didn’t know what my life would be like, but I knew I’d lose grandpa’s knife. Since it meant more to my father than me, I knew he should keep it. And he did. Some thirty years later he brings it out. The warm moist Florida air hasn’t been kind to the knife.

“Here,” he said. “Take your grandfather’s knife back home with you.” I’m glad he still remembered it.

the little pen blade - gone!

It must have been a nice knife at one time. Brass liners, a nice metal shield in the white handle and silver colored bolsters. Grandpa sharpened the blades past usefulness and somewhere snapped the pen blade. I touched up the base of the two remaining blades, but I can’t see a maker’s mark on either blade.


Sic transit gloria mundi!






I’m cleaning out my garage and ran across several old glass knives. Oh! They aren’t what you think. They look like little glass triangles.

Used glass knives....

I used to make them by scratching a thick glass bar and breaking the bar first into a square. A second diagonal scratch and a split turned the square into two imperfect triangles. If you did it right you got an incredibly sharp straight edge on each half.

Glass knives and a little bar stock

You could do it with a carbide scribe and glass pliers, but it’s easier to use a machine. The machine? It’s called a glass knife maker, of course.


The broken glass edge is so sharp you can’t find anything sharper, but it’s fragile, very fragile. What are they used for? Despite their fragility, glass knives are used to cut frozen tissue so thin you can look through it. I used these knives to cut transparent sections of tires and to shape resin blocks and samples for the cryo-microtome. With a cryo-microtome you can cut samples so thin you can shine electrons through them. That’s very thin.


A few problems with that edge. It was brittle and dulled quickly. Left overnight, the edge (from absorbing moisture) would be dull and useless. Bump the sample into it a little too hard, and the edge would explode glass shards in your face.


Still, if you wanted to cut tissue, rubber tires, plastic and so many other things so thin you could see, literally see, through your section, you needed a glass knife.