When I started teaching woodworking about 10 years ago, it felt like I was spending more time flattening the sharpening stones than I was teaching.
It’s a common problem in hand-tool classes and shops: As soon as a woodworker finishes up an edge, he or she is so eager to get back to the bench that the stone is left hollow. A few years ago I started making this threat: “Leave my stones hollow and you will be fined one beer.”
That worked. Now I drink too much beer.
Turns out this was a solution in traditional shops as well. Here’s a great quote dug up by the always-digging Jeff Burks.
When the edge requires grinding and whetting, in the former of these operations, viz. the grinding, is performed on a flat rub-stone, similar to what carpenters sharpen their plane-irons on, with the application of water. This stone is about six inches broad, and eighteen long, and so careful are they to keep its surface flat, that it is a regulation in the work-shops, for every workman, after using the stone, to write his name upon it with a piece of coal; when, if his successor finds it left so uneven, that a halfpenny can be passed underneath the edge of an iron, straight-edged, laid upon it, the former workman is subjected to a fine for his carelessness.
— From “The Technical Repository: On the advantages of improving the qualities of Cutting Instruments, by Burnishing, and thereby condensing their Edges.” by Thomas Gill: Volume 8 – London, 1826
— Christopher Schwarz
6×18″ stone!
I want one. Now.
A halfpenny of the era would have been the same thickness as a quarter dollar (US) which means ~0.07″ flatness over 6″ or 18″ depending on interpretation of “can be passed underneath”. Translating that to a 2″ wide stone would be ~.008″ hollow allowed without a fine, something like a thin rule, not a coin would be needed for the test. Assuming I haven’t totally blown my rough math or coin research.
pls provide a citation for that wonderful pencil, mr schwarz!
http://amzn.com/B000JQSV7E
It’s a really good lead holder. Use it all the time.
So now they can speed things up, and write ‘IOU beer’ on the stone! A good time-saving measure.
I heard a story from Steve Pang of NYC (who taught me great deal about woodwork among other things) when I was younger and just starting to working as a woodworker. I must admit this story was told to me after I left one of the shop’s water stones in shall we say less-than-perfect shape. When he was learning woodworking in China, they had the same problem. There was a huge sharpening stone in the shop and it would become hopelessly concave after a while. Once the stone was unusable, an apprentice would take the stone into the yard, tie a rope to it and drag it about until the stone was flat enough to dress properly.
He also noted that the master of the shop enjoyed these little walks, while everyone else hated them.