Thread: TNT old school advice?

I think this is what the paper insert was describing. The flexibility of the blade near the edge is checked by holding the blade nearly parallel with the nail and dragging the region of the blade near the bevel along the nail to distort the blade. As MattCB wrote, this will reveal minute cracks.

This is not the same as the standard TNT which is done by holding the blade perpendicular to the nail to assess the actual edge of the blade.