Flattening Traditional Oilstones
I have been watching Larry Williams excellent new dvd on the making of traditional side escapement wooden planes, which has just been published by Lie-Nielsen
The working example is a matched pair, a round and a hollow.
He makes all the blades for his planes and has an interesting sharpening technique which I intend to try. He dresses and flattens the surface of his oilstones, both man made and Arkansas, with a diamond stone. The slurry is left on the stone.
I like to rub two 800grit stones together after flattening to ensure that they cut agressively from the beginning. (800 and 1200 work as well). If abrasive paper is used to flatten waterstones, they become glazed as the paper blunts. This means that they do not cut quickly in the beginning. After a few minutes of use the surface breaks down and fast cutting commences.
It seems likely that the slurry left on an Arkansas stone will overcome one of their main drawbacks, i.e. that they cut rather slowly.
Garrett Hack uses another cunning technique to combat this problem, he soups up the cutting action with a small blob of diamond paste.
Larry is in the business of making plane blades from scratch, and therefore does a great deal of back flattening and sharpening. He made a most significant comment about the speed with which Arkansas stones loose their flatness.